Nondualism

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In spirituality, nondualism, also called non-duality, means "not two" or "one undivided without a second". Nondualism primarily refers to a mature state of consciousness, in which the dichotomy of I-other is 'transcended', and awareness is described as 'centerless' and 'without dichotomies'. Although this state of consciousness may seem to appear spontaneous, it usually is the "result" of prolonged ascetic or meditative/contemplative practice, which includes ethical injunctions. While the term "nondualism" is derived from Advaita Vedanta, descriptions of nondual consciousness can be found within Hinduism (Turiya, sahaja), Buddhism (Buddha-nature, rigpa, shentong), and western Christian and neo-Platonic traditions (henosis, mystical union).

The Asian idea of nondualism developed in the Vedic and post-Vedic Hindu philosophies, as well as in the Buddhist traditions.^[3] The oldest traces of nondualism in Indian thought are found as Advaita in the earlier Hindu Upanishads such as Brihadaranyaka Upanishad, as well as other pre-Buddhist Upanishads such as the Chandogya Upanishad, which emphasizes the unity of individual soul called Atman and the Supreme called Brahman. In Hinduism, nondualism has more commonly become associated with the Advaita Vedanta tradition of Adi Shankara.^[4]

The Buddhist tradition added the teachings of śūnyatā; the two truths doctrine, the nonduality of the absolute and the relative truth,^[5][6] and the Yogachara notion of "mind/thought only" (citta-matra) or "representation-only" (vijñaptimātra).^[4] Vijñapti-mātra and the two truths doctrine, coupled with the concept of Buddha-nature, have also been influential concepts in the subsequent development of Mahayana Buddhism, not only in India, but also in China and Tibet, most notably the Chán (Zen) and Dzogchen traditions.

Western Neo-Platonism is an essential element of both Christian contemplation and mysticism, and of Western esotericism and modern spirituality, especially Unitarianism, Transcendentalism, Universalism and Perennialism.

Etymology

Advaita of Hinduism and Advaya of Buddhism both refer to nondualism.

"Advaita" (अद्वैत) is from Sanskrit roots a, not; dvaita, dual, and is usually translated as "nondualism", "nonduality" and "nondual". The term "nondualism" and the term "advaita" from which it originates are polyvalent terms. The English word's origin is the Latin duo meaning "two" prefixed with "non-" meaning "not".

"Advaya" (अद्वय) is also a Sanskrit word that means "identity, unique, not two, without a second," and typically refers to the two truths doctrine of Mahayana Buddhism, especially Madhyamaka.
One of the earliest usage of the word Advaita is found in verse 4.3.32 of the Brihadaranyaka Upanishad (~800 BCE), and in verses 7 and 12 of the Mandukya Upanishad (variously dated to have been composed between 500 BCE to 200 CE).^[7] The term appears in the Brihadaranyaka Upanishad in the section with a discourse of the oneness of Atman and Brahman, as follows:^[8]

An ocean is that one seer, without any duality [Advaita]; this is the Brahma-world, O King. Thus did Yajnavalkya teach him. This is his highest goal, this is his highest success, this is his highest world, this is his highest bliss. All other creatures live on a small portion of that bliss.

— Brihadaranyaka Upanishad 4.3.32, ^[9][10][11]

The English term "nondual" was also informed by early translations of the Upanishads in Western languages other than English from 1775. These terms have entered the English language from literal English renderings of "advaita" subsequent to the first wave of English translations of the Upanishads. These translations commenced with the work of Müller (1823–1900), in the monumental Sacred Books of the East (1879).

Max Müller rendered "advaita" as "Monism", as have many recent scholars.^[12][13][14] However, some scholars state that "advaita" is not really monism.^[15]

Definitions

Nondualism is a fuzzy concept, for which many definitions can be found.^{[note 2]}
According to Espín and Nickoloff, "nondualism" is the thought in some Hindu, Buddhist and Taoist schools, which

... teaches that the multiplicity of the universe is reducible to one essential reality."^[16]

According to Jeff Foster,

'Non-duality'[...] points to the essential oneness (wholeness, completeness, unity) of life, a wholeness which exists here and now, prior to any apparent separation [...] despite the compelling appearance of separation and diversity there is only one universal essence, one reality. Oneness is all there is – and we are included.^{[web 2]}

Jeff Foster further explains

What you are is simply this open space of awareness (consciousness, awakeness, Being) in which absolutely everything seems to come and go, and that space is already at rest; it’s already Home.^{[web 2]}

David Loy, who sees non-duality between subject and object as a common thread in Taoism, Mahayana Buddhism, and Advaita Vedanta,^{[17][note 3]} distinguishes "Five Flavors Of Nonduality":^{[web 3]}

1. The negation of dualistic thinking in pairs of opposites. The Yin-Yang symbol of Taoism symbolises the transcendence of this dualistic way of thinking.^{[web 3]}
2. Monism, the nonplurality of the world. Although the phenomenal world appears as a plurality of "things", in reality they are "of a single cloth".^{[web 3]}
3. Advaita, the nondifference of subject and object, or nonduality between subject and object.^{[web 3]}
4. Advaya, the identity of phenomena and the Absolute, the "nonduality of duality and nonduality",^{[web 3]} c.q. the nonduality of relative and ultimate truth as found in Madhyamaka and the two truths doctrine.
5. Mysticism, a mystical unity between God and man.^{[web 3]}

The idea of nondualism is typically contrasted with dualism, with dualism defined as the view that the universe and the nature of existence consists of two realities, such as the God and the world, or as God and Devil, or as mind and matter, and so on.^[20][21]

The idea of a "nondual consciousness" has gained attraction and popularity in western spirituality and New Age-thinking. It is recognized in the Asian traditions, but also in western and Mediterranean religious traditions, and in western philosophy.^[22] Nondual consciousness is perceived in a wide variety of religious traditions:

• Hinduism:
  • Upanishad^[23]
  • The Advaita Vedanta of Shankara^[24][23]
  • Tantra^[25] and Kashmira Shaivism^[26][25]
  • Ramana Maharshi
• Buddhism:
  • "Shūnyavāda or the Mādhyamika school",^[27][28]
  • "Vijnānavāda or the Yogācāra school",^[27][29]
  • Tathagatagarbha-thought^[29]
  • Vajrayana-buddhism^[30]
  • Zen-buddhism^[31]
  • Tibetan Buddhism,^[32] including Dzogchen^[32] and Mahamudra^[33]
• Sikhism^[34]
• Taoism^[35]
• Subud^[22]
• Abrahamic traditions:
  • Sufism^[35]
• Western philosophy:
  • Neo-platonism^{[citation needed]}

Hinduism

"Advaita" refers to nondualism, non-distinction between realities, the oneness of Atman and Brahman, as in Vedanta, Shaktism and Shaivism.^[36] Although the term is best known from the Advaita Vedanta school of Adi Shankara, "advaita" is used in treatises by numerous medieval era Indian scholars, as well as modern schools and teachers.^{[note 4]}

The Hindu concept of Advaita refers to the idea that all of the universe is one essential reality, and that all facets and aspects of the universe is ultimately an expression or appearance of that one reality.^[36] According to Dasgupta and Mohanta, non-dualism developed in various strands of Indian thought, both Vedic and Buddhist, from the Upanishadic period onward.^[3] The oldest traces of nondualism in Indian thought may be found in the Chandogya Upanishad, which pre-dates the earliest Buddhism. Pre-sectarian Buddhism may also have been responding to the teachings of the Chandogya Upanishad, rejecting some of its Atman-Brahman related metaphysics.^{[37][note 5]}
Advaita appears in different shades in various schools of Hinduism such as in Advaita Vedanta, Vishishtadvaita Vedanta (Vaishnavism), Suddhadvaita Vedanta (Vaishnavism), Shaivism and Shaktism.^[36][40][41] It implies, in Advaita Vedanta of Adi Shankara, that all of the reality is Brahman,^[36] and that the Atman (soul, self) and Brahman (ultimate unchanging reality) are one.^[42][43] Advaita ideas of schools within Hinduism contrasts with its Dvaita schools such as of Madhvacharya who stated that the experienced reality and God are two (dual) and distinct.^[44][45]

Vedanta

Several schools of Vedanta teach a form of nondualism. The best-known is Advaita Vedanta, but other nondual Vedanta schools also have a significant influence and following, such as Vishishtadvaita Vedanta and Shuddhadvaita,^[36] both of which are bhedabheda.

Advaita Vedanta

Swans are important figures in Advaita

The nonduality of the Advaita Vedantins is of the identity of Brahman and the Atman.^[46] Advaita has become a broad current in Indian culture and religions, influencing subsequent traditions like Kashmir Shaivism.

The oldest surviving manuscript on Advaita Vedanta is by Gauḍapāda (6th century CE),^[4] who has traditionally been regarded as the teacher of Govinda bhagavatpāda and the grandteacher of Shankara. Advaita is best known from the Advaita Vedanta tradition of Adi Shankara, who states that Brahman is pure Being, Consciousness and Bliss (Sat-cit-ananda).^[47]

Advaita, states Murti, is the knowledge of Brahman and self-consciousness (Vijnana) without differences.^[48] The goal of Vedanta is to know the "truly real" and thus become one with it.^[49] According to Advaita Vedanta, Brahman is the highest Reality,^[50][51][52] The universe, according to Advaita philosophy, does not simply come from Brahman, it is Brahman. Brahman is the single binding unity behind the diversity in all that exists in the universe.^[51] Brahman is also that which is the cause of all changes.^[51][53][54] Brahman is the "creative principle which lies realized in the whole world".^[55]

The nondualism of Advaita, relies on the Hindu concept of Ātman which is a Sanskrit word that means "real self" of the individual,^[56][57] "essence",^{[web 5]} and soul.^[56][58] Ātman is the first principle,^[59] the true self of an individual beyond identification with phenomena, the essence of an individual. Atman is the Universal Principle, one eternal undifferentiated self-luminous consciousness, asserts Advaita Vedanta school of Hinduism.^[60][61]

Advaita Vedanta philosophy considers Atman as self-existent awareness, limitless, non-dual and same as Brahman.^[62] Advaita school asserts that there is "soul, self" within each living entity which is fully identical with Brahman.^[63][64] This identity holds that there is One Soul that connects and exists in all living beings, regardless of their shapes or forms, there is no distinction, no superior, no inferior, no separate devotee soul (Atman), no separate God soul (Brahman).^[63] The Oneness unifies all beings, there is the divine in every being, and all existence is a single Reality, state the Advaita Vedantins.^[65] The nondualism concept of Advaita Vedanta asserts that each soul is non-different from the infinite Brahman.^[66]

Advaita Vedanta – Three levels of reality

Advaita Vedanta adopts sublation as the criterion to postulate three levels of ontological reality:^[67][68]

• Pāramārthika (paramartha, absolute), the Reality that is metaphysically true and ontologically accurate. It is the state of experiencing that "which is absolutely real and into which both other reality levels can be resolved". This experience can't be sublated (exceeded) by any other experience.^[67][68]
• Vyāvahārika (vyavahara), or samvriti-saya,^[69] consisting of the empirical or pragmatic reality. It is ever-changing over time, thus empirically true at a given time and context but not metaphysically true. It is "our world of experience, the phenomenal world that we handle every day when we are awake". It is the level in which both jiva (living creatures or individual souls) and Iswara are true; here, the material world is also true.^[68]
• Prāthibhāsika (pratibhasika, apparent reality, unreality), "reality based on imagination alone". It is the level of experience in which the mind constructs its own reality. A well-known example is the perception of a rope in the dark as being a snake.^[68]

Similarities and differences with Buddhism

Scholars state that Advaita Vedanta was influenced by Mahayana Buddhism, given the common terminology and methodology and some common doctrines.^[70][71] Eliot Deutsch and Rohit Dalvi state:

In any event a close relationship between the Mahayana schools and Vedanta did exist, with the latter borrowing some of the dialectical techniques, if not the specific doctrines, of the former.^[72]

Advaita Vedanta is related to Madhyamaka via Gaudapada, who took over the Buddhist doctrine that ultimate reality is pure consciousness (vijñapti-mātra).^[4] Shankara harmonised Gaudapada's ideas with the Upanishadic texts, and provided an orthodox hermeneutical basis for heterodox Buddhist phenomology.^[73][74]

Gaudapada adopted the Buddhist concept of ultimate reality is pure consciousness (vijñapti-mātra).^[4] The Buddhist term is often used interchangeably with the term citta-mātra, but they have different meanings. The standard translation of both terms is "consciousness-only" or "mind-only." Advaita Vedanta has been called "idealistic monism" by scholars, but some disagree with this label.^[75][76] Another concept found in both Madhyamaka Buddhism and Advaita Vedanta is Ajativada ("ajāta"), which Gaudapada adopted from Nagarjuna's philosophy.^{[77][78][note 6]} Gaudapada "wove [both doctrines] into a philosophy of the Mandukaya Upanisad, which was further developed by Shankara.^{[80][note 7]}

Michael Comans states there is a fundamental difference between Buddhist thought and that of Gaudapada, in that Buddhism has as its philosophical basis the doctrine of Dependent Origination according to which "everything is without an essential nature (nissvabhava), and everything is empty of essential nature (svabhava-sunya)", while Gaudapada does not rely on this principle at all. Gaudapada's Ajativada is an outcome of reasoning applied to an unchanging nondual reality according to which "there exists a Reality (sat) that is unborn (aja)" that has essential nature (svabhava), and this is the "eternal, fearless, undecaying Self (Atman) and Brahman".^[82] Thus, Gaudapada differs from Buddhist scholars such as Nagarjuna, states Comans, by accepting the premises and relying on the fundamental teaching of the Upanishads.^[82] Among other things, Vedanta school of Hinduism holds the premise, "Atman exists, as self evident truth", a concept it uses in its theory of nondualism. Buddhism, in contrast, holds the premise, "Atman does not exist (or, An-atman) as self evident".^[83][84][85]

Mahadevan suggests that Gaudapada adopted Buddhist terminology and adapted its doctrines to his Vedantic goals, much like early Buddhism adopted Upanishadic terminology and adapted its doctrines to Buddhist goals; both used pre-existing concepts and ideas to convey new meanings.^[86] Dasgupta and Mohanta note that Buddhism and Shankara's Advaita Vedanta are not opposing systems, but "different phases of development of the same non-dualistic metaphysics from the Upanishadic period to the time of Sankara."^[3]

Vishishtadvaita Vedanta

Ramanuja, founder of Vishishtadvaita Vedanta, taught 'qualified nondualism' doctrine.

See also: Bhedabheda

Vishishtadvaita Vedanta is another main school of Vedanta and teaches the nonduality of the qualified whole, in which Brahman alone exists, but is characterized by multiplicity. It can be described as "qualified monism," or "qualified non-dualism," or "attributive monism."

According to this school, the world is real, yet underlying all the differences is an all-embracing unity, of which all "things" are an "attribute." Ramanuja, the main proponent of Vishishtadvaita philosophy contends that the Prasthana Traya ("The three courses") – namely the Upanishads, the Bhagavad Gita, and the Brahma Sutras – are to be interpreted in a way that shows this unity in diversity, for any other way would violate their consistency.

Vedanta Desika defines Vishishtadvaita using the statement: Asesha Chit-Achit Prakaaram Brahmaikameva Tatvam – "Brahman, as qualified by the sentient and insentient modes (or attributes), is the only reality."

Neo-Vedanta

Neo-Vedanta, also called "neo-Hinduism"^[87] is a modern interpretation of Hinduism which developed in response to western colonialism and orientalism, and aims to present Hinduism as a "homogenized ideal of Hinduism"^[88] with Advaita Vedanta as its central doctrine.^[89]
Neo-Vedanta, as represented by Vivekananda and Radhakrishnan, is indebted to Advaita vedanta, but also reflects Advaya-philosophy. A main influence on neo-Advaita was Ramakrishna, himself a bhakta and tantrika, and the guru of Vivekananda. According to Michael Taft, Ramakrishna reconciled the dualism of formlessness and form.^[90] Ramakrishna regarded the Supreme Being to be both Personal and Impersonal, active and inactive:

When I think of the Supreme Being as inactive – neither creating nor preserving nor destroying – I call Him Brahman or Purusha, the Impersonal God. When I think of Him as active – creating, preserving and destroying – I call Him Sakti or Maya or Prakriti, the Personal God. But the distinction between them does not mean a difference. The Personal and Impersonal are the same thing, like milk and its whiteness, the diamond and its lustre, the snake and its wriggling motion. It is impossible to conceive of the one without the other. The Divine Mother and Brahman are one.^[91]

Radhakrishnan acknowledged the reality and diversity of the world of experience, which he saw as grounded in and supported by the absolute or Brahman.^{[web 6][note 8]} According to Anil Sooklal, Vivekananda's neo-Advaita "reconciles Dvaita or dualism and Advaita or non-dualism":^[93]

The Neo-Vedanta is also Advaitic inasmuch as it holds that Brahman, the Ultimate Reality, is one without a second, ekamevadvitiyam. But as distinguished from the traditional Advaita of Sankara, it is a synthetic Vedanta which reconciles Dvaita or dualism and Advaita or non-dualism and also other theories of reality. In this sense it may also be called concrete monism in so far as it holds that Brahman is both qualified, saguna, and qualityless, nirguna.^[93]

Radhakrishnan also reinterpreted Shankara's notion of maya. According to Radhakrishnan, maya is not a strict absolute idealism, but "a subjective misperception of the world as ultimately real."^{[web 6]} According to Sarma, standing in the tradition of Nisargadatta Maharaj, Advaitavāda means "spiritual non-dualism or absolutism",^[94] in which opposites are manifestations of the Absolute, which itself is immanent and transcendent:^[95]

All opposites like being and non-being, life and death, good and evil, light and darkness, gods and men, soul and nature are viewed as manifestations of the Absolute which is immanent in the universe and yet transcends it.^[96]

Kashmir Shaivism

Advaita is also a central concept in various schools of Shaivism, such as Kashmir Shaivism^[36] and Shiva Advaita.
Kashmir Shaivism is a school of Śaivism, described by Abhinavagupta^{[note 9]} as "paradvaita", meaning "the supreme and absolute non-dualism".^{[web 7]} It is categorized by various scholars as monistic^[97] idealism (absolute idealism, theistic monism,^[98] realistic idealism,^[99] transcendental physicalism or concrete monism^[99]).

Kashmir Saivism is based on a strong monistic interpretation of the Bhairava Tantras and its subcategory the Kaula Tantras, which were tantras written by the Kapalikas.^[100] There was additionally a revelation of the Siva Sutras to Vasugupta.^[100] Kashmir Saivism claimed to supersede the dualistic Shaiva Siddhanta.^[101] Somananda, the first theologian of monistic Saivism, was the teacher of Utpaladeva, who was the grand-teacher of Abhinavagupta, who in turn was the teacher of Ksemaraja.^[100][102]

The philosophy of Kashmir Shaivism can be seen in contrast to Shankara's Advaita.^[103] Advaita Vedanta holds that Brahman is inactive (niṣkriya) and the phenomenal world is an illusion (māyā). In Kashmir Shavisim, all things are a manifestation of the Universal Consciousness, Chit or Brahman.^[104][105] Kashmir Shavisim sees the phenomenal world (Śakti) as real: it exists, and has its being in Consciousness (Chit).^[106]

Kashmir Shaivism was influenced by, and took over doctrines from, several orthodox and heterodox Indian religious and philosophical traditions.^[107] These include Vedanta, Samkhya, Patanjali Yoga and Nyayas, and various Buddhist schools, including Yogacara and Madhyamika,^[107] but also Tantra and the Nath-tradition.^[108]

Contemporary vernacular Advaita

Advaita is also part of other Indian traditions, which are less strongly, or not all, organised in monastic and institutional organisations. Although often called "Advaita Vedanta," these traditions have their origins in vernacular movements and "householder" traditions, and have close ties to the Nath, Nayanars and Sant Mat traditions.

Ramana Maharshi

Ramana Maharshi (1879–1950) explained his insight using Shaiva Siddhanta, Advaita Vedanta and Yoga teachings.

Ramana Maharshi (30 December 1879 – 14 April 1950) is widely acknowledged as one of the outstanding Indian gurus of modern times.^[109] Ramana's teachings are often interpreted as Advaita Vedanta, though Ramana Maharshi never "received diksha (initiation) from any recognised authority".^{[web 8]} Ramana himself did not call his insights advaita:

D. Does Sri Bhagavan advocate advaita?

M. Dvaita and advaita are relative terms. They are based on the sense of duality. The Self is as it is. There is neither dvaita nor advaita. "I Am that I Am."^{[note 10]} Simple Being is the Self.^[111]

Neo-Advaita

Neo-Advaita is a New Religious Movement based on a modern, western interpretation of Advaita Vedanta, especially the teachings of Ramana Maharshi.^[112] According to Arthur Versluis, neo-Advaita is part of a larger religious current which he calls immediatism,^{[113][web 11]} "the assertion of immediate spiritual illumination without much if any preparatory practice within a particular religious tradition."^{[web 11]} Neo-Advaita is criticized for this immediatism and its lack of preparatory practices.^{[114][note 11][116][note 12]} Notable neo-advaita teachers are H. W. L. Poonja^[117][112] and his students Gangaji,^[118] Andrew Cohen,^{[note 13]}, and Eckhart Tolle.^[112]

Natha Sampradaya and Inchegeri Sampradaya

The Natha Sampradaya, with Nath yogis such as Gorakhnath, introduced Sahaja, the concept of a spontaneous spirituality. Sahaja means "spontaneous, natural, simple, or easy".^{[web 15]} According to Ken Wilber, this state reflects nonduality.^[120]

Buddhism

The Advaya concept of nonduality refers to the "non-two" understanding of reality, which has its origins in Madhyamaka-thought, which in turn is built on earlier Buddhist thought, and expressed in the two truths doctrine. In Nagarjuna's interpretation it is the non-duality of conventional and ultimate truth, or the overcoming of dichotomies such as that between samsara (conditioned or relative reality, rebirth) and nirvana (unconditioned and absolute reality, liberation).^[121][122]

Nondualism in Buddhism is explicitly represented by the concept of Buddha-nature, and Tibetan concepts like rigpa and shentong. It has its roots in Buddhist ideas of luminous mind, the "pure" consciousness which shines through when purified from the defilements of hatred, anger and ignorance. Nondualism can also be found in Yogacara thought, and its concept of the alaija-vijnana. Subsequently, combinations of Buddha-nature thought and Yogacara, and also of Yogacara and Madhyamaka, developed in India, Tibet and China, and can be found in Tibetan Buddhism and Zen.
The nonduality of relative and ultimate truth was further developed and re-interpreted in Chinese Buddhism, where the two truths doctrine came to refer to the nonduality of nirvana and samsara, re-incorporating essentialist notions.

Indian Buddhism

Madhyamaka – nonduality of conventional and ultimate truth

Nagarjuna and Aryadeva

In Madhyamaka Buddhism Advaya refers to the nonduality of conventional and ultimate truth,^[123] or the relative (phenomenal) world and the Absolute, such as in samsara and nirvana.^[36] Madhyamaka, also known as Śūnyavāda, refers primarily to a Mahāyāna Buddhist school of philosophy^[124] founded by Nāgārjuna.

In Madhyamaka, the two truths refer to conventional and ultimate truth.^[125] The ultimate truth is "emptiness", or non-existence of inherently existing "things",^[126] and the "emptiness of emptiness": emptiness does not in itself constitute an absolute reality. Conventionally, "things" exist, but ultimately, they are "empty" of any existence on their own, as described in Nāgārjuna's Mūlamadhyamakakārikā:

The Buddha's teaching of the Dharma is based on two truths: a truth of worldly convention and an ultimate truth. Those who do not understand the distinction drawn between these two truths do not understand the Buddha's profound truth. Without a foundation in the conventional truth the significance of the ultimate cannot be taught. Without understanding the significance of the ultimate, liberation is not achieved.^{[note 14]}

"Emptiness" is a consequence of pratītyasamutpāda (dependent arising),^[127] the teaching that no dharma ("thing") has an existence of its own, but always comes into existence in dependence on other dharmas. According to Madhyamaka all phenomena are empty of "substance" or "essence" (Sanskrit: svabhāva) because they are dependently co-arisen. Likewise it is because they are dependently co-arisen that they have no intrinsic, independent reality of their own. Madhyamaka also rejects the existence of an absolute reality or Self.^[128] Ultimately, "absolute reality" is not an absolute, or the non-duality of a personal self and an absolute Self, but the deconstruction of such reifications.

It also means that there is no "transcendental ground," and that "ultimate reality" has no existence of its own, but is the negation of such a transcendental reality, and the impossibility of any statement on such an ultimately existing transcendental reality: it is no more than a fabrication of the mind.^{[web 16][note 15]} Susan Kahn further explains:

Ultimate truth does not point to a transcendent reality, but to the transcendence of deception. It is critical to emphasize that the ultimate truth of emptiness is a negational truth. In looking for inherently existent phenomena it is revealed that it cannot be found. This absence is not findable because it is not an entity, just as a room without an elephant in it does not contain an elephantless substance. Even conventionally, elephantlessness does not exist. Ultimate truth or emptiness does not point to an essence or nature, however subtle, that everything is made of.^{[web 17]}

In Madhyamaka-Buddhism, "Advaya" is an epistemological approach.^[48] It is the recognition that ultimately everything is impermanent (anicca) and devoid of "self" or "essence" (anatta),^{[129][130][131]} and that this emptiness does not constitute an "absolute" reality in itself.^{[note 16]}.

The later Madhyamikas, states Yuichi Kajiyama, developed the Advaya definition as a means to Nirvikalpa-Samadhi by suggesting that "things arise neither from their own selves nor from other things, and that when subject and object are unreal, the mind, being not different, cannot be true either; thereby one must abandon attachment to cognition of nonduality as well, and understand the lack of intrinsic nature of everything". Thus, the Buddhist nondualism or Advaya concept became a means to realizing absolute emptiness.^[132]

Yogacara

In Yogacara, adhyava may also refer to overcoming the dichotomies of cognitum and cognition imposed by conceptual thought.^[36] Yogācāra (Sanskrit; literally: "yoga practice"; "one whose practice is yoga")^[133] is an influential school of Buddhist philosophy and psychology emphasizing phenomenology and (some argue)^{[clarification needed]} ontology^[134] through the interior lens of meditative and yogic practices. It developed within Indian Mahāyāna Buddhism in about the 4th century CE.^[135]
The concept of adyava in Yogacara is an epistemological stance on the nature of knowledge. Early Buddhism schools such as Sarvastivada and Sautrāntika, that thrived through the early centuries of the common era, postulated a dualism, dvaya, wherein grasping (grahaka, "cognition") and the grasped (gradya, "cognitum")^[136] both are really existing.^{[132][136][137]} Yogacara postulates an advaya of grasping and the grasped, stating that only the mind^[132] (citta-mātra) or the representations we cognize (vijñapti-mātra),^{[138][note 17]} really exist.^{[132][136][138]}

In Yogacara-thought, cognition is a modification of the base-consciousness, alaya-vijnana. By the reification of these modifications into separate consciousnesses, the Eighth Consciousnesses of Yogacara came into existence.^[139] In later Buddhist thought, which took an idealistic turn, the storehouse-consciousness or base-consciousness came to be seen as a pure consciousness, from which everything arises. According to the Lankavatara Sutra and the schools of Chan/Zen Buddhism, the alaya-vijnana is identical with the tathagata-garbha^{[note 18]}, and is fundamentally pure.^[140] Vijñapti-mātra, coupled with Buddha-nature or tathagatagarba, has been an influential concept in the subsequent development of Mahayana Buddhism, not only in India, but also in China and Tibet, most notable in the Chán (Zen) and Dzogchen traditions.

According to Kochumuttom, Yogacara is a realistic pluralism. It does not deny the existence of individual beings, but denies the following:^[76]

1. That the absolute mode of reality is consciousness/mind/ideas,
2. That the individual beings are transformations or evolutes of an absolute consciousness/mind/idea,
3. That the individual beings are but illusory appearances of a monistic reality.^[141]

Vijñapti-mātra, "consciousness-only" or "representation-only" is one of the main features of Yogācāra philosophy. It is often used interchangeably with the term citta-mātra, but they have different meanings. The standard translation of both terms is "consciousness-only" or "mind-only." Several modern researchers object to this translation, and the accompanying label of "absolute idealism" or "idealistic monism".^[76] A better translation for vijñapti-mātra is representation-only.^[138]

Vijñapti-mātra then means "mere representation of consciousness":

[T]he phrase vijñaptimātratā-vāda means a theory which says that the world as it appears to the unenlightened ones is mere representation of consciousness. Therefore, any attempt to interpret vijñaptimātratā-vāda as idealism would be a gross misunderstanding of it.^[138]

The term vijñapti-mātra replaced the "more metaphysical"^[142] term citta-mātra used in the Lankavatara Sutra.^[143] The Lankavatara Sutra "appears to be one of the earliest attempts to provide a philosophical justification for the Absolutism that emerged in Mahayana in relation to the concept of Buddha".^[144] It uses the term citta-mātra, which means properly "thought-only". By using this term it develops an ontology, in contrast to the epistemology of the term vijñapti-mātra. The Lankavatara Sutra equates citta and the absolute. According to Kochumuttom, this is not the way Yogacara uses the term vijñapti:^[145]

[T]he absolute state is defined simply as emptiness, namely the emptiness of subject–object distinction. Once thus defined as emptiness (sunyata), it receives a number of synonyms, none of which betray idealism.^[146]

The Yogācārins defined three basic modes by which we perceive our world. These are referred to in Yogācāra as the three natures of perception. They are:

1. Parikalpita (literally, "fully conceptualized"): "imaginary nature", wherein things are incorrectly comprehended based on conceptual construction, through attachment and erroneous discrimination.
2. Paratantra (literally, "other dependent"): "dependent nature", by which the correct understanding of the dependently originated nature of things is understood.
3. Pariniṣpanna (literally, "fully accomplished"): "absolute nature", through which one comprehends things as they are in themselves, uninfluenced by any conceptualization at all.

Also, regarding perception, the Yogācārins emphasized that our everyday understanding of the existence of external objects is problematic, since in order to perceive any object (and thus, for all practical purposes, for the object to "exist"), there must be a sensory organ as well as a correlative type of consciousness to allow the process of cognition to occur.

Buddha-nature

Vijñapti-mātra and the two truths doctrine, as understood in Chinese Buddhism, are closely linked to Buddha-nature. Those teachings have had a profound influence on Mahayana Buddhism, not only in India, but also in China and Tibet, most notably the Chán (Zen) and Dzogchen traditions. They may be related to an archaic form of Buddhism which is close to Brahmanical beliefs, elements of which are preserved in the Nikayas,^{[147][148][149][150]} and survived in the Mahayana tradition.^[151][152] Contrary to popular opinion, the Theravada and Mahayana traditions may be "divergent, but equally reliable records of a pre-canonical Buddhism which is now lost forever."^[151] The Mahayana tradition may have preserved a very old, "pre-Canonical" tradition, which was largely, but not completely, left out of the Theravada-canon.^[152]

The Buddhist teachings on the Buddha-nature may be regarded as a form of nondualism.^[153] Buddha-nature is the essential element that allows sentient beings to become Buddhas.^[154] The term, Buddha nature, is a translation of the Sanskrit coinage, 'Buddha-dhātu', which seems first to have appeared in the Mahayana Mahaparinirvana Sutra,^[155] where it refers to 'a sacred nature that is the basis for [beings'] becoming buddhas.'^[156] The term seems to have been used most frequently to translate the Sanskrit "Tathāgatagarbha". The Sanskrit term "tathāgatagarbha" may be parsed into tathāgata ("the one thus gone", referring to the Buddha) and garbha ("womb").^{[note 19]} The tathagatagarbha, when freed from avidya ("ignorance"), is the dharmakaya, the Absolute.

Tantric Buddhism

Tantra is a religious tradition that originated in India in the middle of the first millennium CE, and has been practiced by Buddhists, Hindus and Jains throughout south and southeast Asia.^[157] It views humans as a microcosmos which mirrors the macrocosmos.^[158] Its aim is to gain access to the energy or enlightened consciousness of the godhead or absolute, by embodying this energy or consciousness through rituals.^[158] It views the godhead as both transcendent and immanent, and views the world as real, and not as an illusion:^[159]

Rather than attempting to see through or transcend the world, the practitioner comes to recognize "that" (the world) as "I" (the supreme egoity of the godhead): in other words, s/he gains a "god's eye view" of the universe, and recognizes it to be nothing other than herself/himself. For East Asian Buddhist Tantra in particular, this means that the totality of the cosmos is a "realm of Dharma", sharing an underlying common principle.^[160]

Ramakrishna too was a tantric adherent, although his tantric background was overlaid and smoothed with an Advaita interpretation by his student Vivekananda.^[161]

East-Asian Buddhism

Chinese Buddhism – nonduality of mundane and highest reality

In Chinese Buddhism the Two truths doctrine was interpreted as an ontological teaching of three truths,^[162] states Whalen Lai, wherein "samsaric being and nirvanic emptiness as well any and all distinctions are not two".^[163] The Chinese Buddhist scholars posited that there is a third truth above the mundane truth of samsaric being and the highest truth nirvanic emptiness (sunyata).^[164][162] In one description, everything is posited to be simultaneously "empty, real and neither".^[163] According to Lai, most scholars of Chinese Buddhism, unlike Nagarjuna, failed to realize that the two truths were epistemic, not ontological.^[164] This mistake was identified and discussed by Jizang of Sanlun school.^[164]
Chinese Buddhism evolved over time.^[165] Before 400 CE, states Lai, the Chinese understood the Buddhist doctrine to be that "karmic rebirth entailed the transmigration of soul".^[165] It was monk Mindu who understood that the Buddha taught a no soul doctrine, and he tried to explain this to his Buddhist sangha, but was vilified for denying the existence of soul.^[165] Mindu's ideas, however, began a momentum that led to the emergence of six prajna schools in the 4th and 5th century CE.^[165] In the 6th century CE it became clear that anatman and sunyata are central Buddhist teachings, which make the postulation of an eternal self problematic.^[166][167]

Another point of confusion was the Two truths doctrine of Madhyamaka, the mundane truth and the highest truth. Chinese thinking took this to refer to two ontological truths: reality exists at two levels, the mundane level of samsara and the highest level of nirvana emptiness. But in Madhyamaka these are two epistemological truths, two different ways to look at reality. The early Chinese scholars supposed that there is an essential truth above the two truths, which unites both these.^[164][167] This three truths doctrine was different from a similarly named doctrine of Yogacara and Indian Buddhism.^[167]

Hua-yen Buddhism

The Huayan school or Flower Garland is a tradition of Mahayana Buddhist philosophy that flourished in China during the Tang period particularly with Fazang (~700 CE). It is based on the Sanskrit Flower Garland Sutra (S. Avataṃsaka Sūtra, C. Huayan Jing) and on a lengthy Chinese interpretation of it, the Huayan Lun. The name Flower Garland is meant to suggest the crowning glory of profound understanding. Huayan teaches the Four Dharmadhatu, four ways to view reality:

1. All dharmas are seen as particular separate events;
2. All events are an expression of the absolute;
3. Events and essence interpenetrate;
4. All events interpenetrate.^[168]

Zen Buddhism

Dogen

The Buddha-nature and Yogacara philosophies have had a strong influence on Chán and Zen. The teachings of Zen are expressed by a set of polarities: Buddha-nature – sunyata;^[169][170] absolute-relative;^[171] sudden and gradual enlightenment.^[172]

The Lankavatara-sutra, a popular sutra in Zen, endorses the Buddha-nature and emphasizes purity of mind, which can be attained in gradations. The Diamond-sutra, another popular sutra, emphasizes sunyata, which "must be realized totally or not at all".^[173] The Prajnaparamita Sutras emphasize the non-duality of form and emptiness: form is emptiness, emptiness is form, as the Heart Sutra says.^[171] According to Chinul, Zen points not to mere emptiness, but to suchness or the dharmadhatu.^[174]

The idea that the ultimate reality is present in the daily world of relative reality fitted into the Chinese culture which emphasized the mundane world and society. But this does not explain how the absolute is present in the relative world. This question is answered in such schemata as the Five Ranks of Tozan^[175] and the Oxherding Pictures.

The continuous pondering of the break-through kōan (shokan^[176]) or Hua Tou, "word head",^[177] leads to kensho, an initial insight into "seeing the (Buddha-)nature.^[178] According to Hori, a central theme of many koans is the "identity of opposites", and point to the original nonduality.^[179][180] Victor Sogen Hori describes kensho, when attained through koan-study, as the absence of subject–object duality.^[181] The aim of the so-called break-through koan is to see the "nonduality of subject and object", ^[179][180] in which "subject and object are no longer separate and distinct."^[182]

Zen Buddhist training does not end with kenshō. Practice is to be continued to deepen the insight and to express it in daily life,^{[183][184][185][186]} to fully manifest the nonduality of absolute and relative.^[187][188] To deepen the initial insight of kensho, shikantaza and kōan-study are necessary. This trajectory of initial insight followed by a gradual deepening and ripening is expressed by Linji Yixuan in his Three Mysterious Gates, the Four Ways of Knowing of Hakuin,^[189] the Five Ranks, and the Ten Ox-Herding Pictures^[190] which detail the steps on the Path.

Essence-function in Korean Buddhism

The polarity of absolute and relative is also expressed as "essence-function". The absolute is essence, the relative is function. They can't be seen as separate realities, but interpenetrate each other. The distinction does not "exclude any other frameworks such as neng-so or 'subject-object' constructions", though the two "are completely different from each other in terms of their way of thinking".^[191] In Korean Buddhism, essence-function is also expressed as "body" and "the body's functions".^[192] A metaphor for essence-function is "a lamp and its light", a phrase from the Platform Sutra, where Essence is lamp and Function is light.^[193]

Tibetan Buddhism

Adyava: Gelugpa Prasangika-Madhyamaka

The Gelugpa school, following Tsongkhapa, adheres to the adyava Prasaṅgika Mādhyamaka view, which states that all phenomena are sunyata, empty of self-nature, and that this "emptiness" is itself only a qualification, not a concretely existing "absolute" reality.^[194]

This view is reiterated by some western Madhyamaka-inspired writers,^{[web 19][web 20][web 21]} stressing that there is no transcendental reality beyond this phenomenal world.^{[web 22][note 20]}

Buddha-nature and the nature of mind

Shentong

In Tibetan Buddhism, the essentialist position is represented by shentong, while the nominalist, or non-essentialist position, is represented by rangtong.
Shentong is a philosophical sub-school found in Tibetan Buddhism. Its adherents generally hold that the nature of mind, the substratum of the mindstream, is "empty" (Wylie: stong) of "other" (Wylie: gzhan), i.e., empty of all qualities other than an inherently existing, ineffable nature. Shentong has often been incorrectly associated with the Cittamātra (Yogacara) position, but is in fact also Madhyamaka,^[195] and is present primarily as the main philosophical theory of the Jonang school, although it is also taught by the Sakya^[196] and Kagyu schools.^[197][198] According to Shentongpa (proponents of shentong), the emptiness of ultimate reality should not be characterized in the same way as the emptiness of apparent phenomena because it is prabhāśvara-saṃtāna, or "luminous mindstream" endowed with limitless Buddha qualities.^[199] It is empty of all that is false, not empty of the limitless Buddha qualities that are its innate nature.

The contrasting Prasaṅgika view that all phenomena are sunyata, empty of self-nature, and that this "emptiness" is not a concretely existing "absolute" reality, is labeled rangtong, "empty of other."^[194]
The shentong-view is related to the Ratnagotravibhāga sutra and the Yogacara-Madhyamaka synthesis of Śāntarakṣita. The truth of sunyata is acknowledged, but not considered to be the highest truth, which is the empty nature of mind. Insight into sunyata is preparatory for the recognition of the nature of mind.

Dzogchen

Dzogchen is concerned with the "natural state" and emphasizes direct experience. The state of nondual awareness is called rigpa.^{[citation needed]} This primordial nature is clear light, unproduced and unchanging, free from all defilements. Through meditation, the Dzogchen practitioner experiences that thoughts have no substance. Mental phenomena arise and fall in the mind, but fundamentally they are empty. The practitioner then considers where the mind itself resides. Through careful examination one realizes that the mind is emptiness.^[200]
Karma Lingpa (1326–1386) revealed "Self-Liberation through seeing with naked awareness" (rigpa ngo-sprod,^{[note 21]}) which is attributed to Padmasambhava.^{[201][note 22]} The text gives an introduction, or pointing-out instruction (ngo-spro), into rigpa, the state of presence and awareness.^[201] In this text, Karma Lingpa writes the following regarding the unity of various terms for nonduality:

With respect to its having a name, the various names that are applied to it are inconceivable (in their numbers).
Some call it "the nature of the mind"^{[note 23]} or "mind itself."
Some Tirthikas call it by the name Atman or "the Self."
The Sravakas call it the doctrine of Anatman or "the absence of a self."
The Chittamatrins call it by the name Chitta or "the Mind."
Some call it the Prajnaparamita or "the Perfection of Wisdom."
Some call it the name Tathagata-garbha or "the embryo of Buddhahood."
Some call it by the name Mahamudra or "the Great Symbol."
Some call it by the name "the Unique Sphere."^{[note 24]}
Some call it by the name Dharmadhatu or "the dimension of Reality."
Some call it by the name Alaya or "the basis of everything."
And some simply call it by the name "ordinary awareness."^{[206][note 25]}

Other eastern religions

Apart from Hinduism and Buddhism, self-proclaimed nondualists have also discerned nondualism in other religious traditions.

Sikhism

Sikh theology suggests human souls and the monotheistic God are two different realities (dualism),^[207] distinguishing it from the monistic and various shades of nondualistic philosophies of other Indian religions.^[208] However, Sikh scholars have attempted to explore nondualism exegesis of Sikh scriptures, such as during the neocolonial reformist movement by Bhai Vir Singh of the Singh Sabha. According to Mandair, Singh interprets the Sikh scriptures as teaching nonduality.^[209]

Taoism

Taijitu

Taoism's wu wei (Chinese wu, not; wei, doing) is a term with various translations^{[note 26]} and interpretations designed to distinguish it from passivity. The concept of Yin and Yang, often mistakenly conceived of as a symbol of dualism, is actually meant to convey the notion that all apparent opposites are complementary parts of a non-dual whole.^[210]

Western traditions

A modern strand of thought sees "nondual consciousness" as a universal psychological state, which is a common stratum and of the same essence in different spiritual traditions.^[2] It is derived from Neo-Vedanta and neo-Advaita, but has historical roots in neo-Platonism, Western esotericism, and Perennialism. The idea of nondual consciousness as "the central essence"^[211] is a universalistic and perennialist idea, which is part of a modern mutual exchange and synthesis of ideas between western spiritual and esoteric traditions and Asian religious revival and reform movements.^{[note 27]}
Central elements in the western traditions are Neo-Platonism, which had a strong influence on Christian contemplation c.q. mysticism, and it's accompanying apophatic theology; and Western esotericism, which also incorporated Neo-Platonism and Gnostic elements including Hermeticism. Western traditions are, among others, the idea of a Perennial Philosophy, Swedenborgianism, Unitarianism, Orientalism, Transcendentalism, Theosophy, and New Age.^[213]

Eastern movements are the Hindu reform movements such as Vivekananda's Neo-Vedanta and Aurobindo's Integral Yoga, the Vipassana movement, and Buddhist modernism.^{[note 28]}

Roman world

Gnosticism

Since its beginning, Gnosticism has been characterized by many dualisms and dualities, including the doctrine of a separate God and Manichaean (good/evil) dualism.^[214] Ronald Miller interprets the Gospel of Thomas as a teaching of "nondualistic consciousness".^[215]

Neoplatonism

The precepts of Neoplatonism of Plotinus (2nd century) assert nondualism.^[216] Neoplatonism had a strong influence on Christian mysticism.
Some scholars suggest a possible link of more ancient Indian philosophies on Neoplatonism, while other scholars consider these claims as unjustified and extravagant with the counter hypothesis that nondualism developed independently in ancient India and Greece.^[217] The nondualism of Advaita Vedanta and Neoplatonism have been compared by various scholars,^[218] such as J. F. Staal,^[219] Frederick Copleston,^[220] Aldo Magris and Mario Piantelli,^[221] Sarvepalli Radhakrishnan,^[222] Gwen Griffith-Dickson,^[223] John Y. Fenton^[224] and Dale Riepe.^[225]

Medieval Abrahamic religions

Christian contemplation and mysticism

The Mystic Marriage of St Catherine, St John the Baptist, St Antony Abbot

In Christian mysticism, contemplative prayer and Apophatic theology are central elements. In contemplative prayer, the mind is focused by constant repetition a phrase or word. Saint John Cassian recommended use of the phrase "O God, make speed to save me: O Lord, make haste to help me".^[226][227] Another formula for repetition is the name of Jesus.^[228][229] or the Jesus Prayer, which has been called "the mantra of the Orthodox Church",^[227] although the term "Jesus Prayer" is not found in the Fathers of the Church.^[230] The author of The Cloud of Unknowing recommended use of a monosyllabic word, such as "God" or "Love".^[231]

Apophatic theology is derived from Neo-Platonism via Pseudo-Dionysius the Areopagite. In this approach, the notion of God is stripped from all positive qualifications, leaving a "darkness" or "unground." It had a strong influence on western mysticism. A notable example is Meister Eckhart, who also attracted attention from Zen-Buddhists like D.T. Suzuki in modern times, due to the similarities between Buddhist thought and Neo-Platonism.

The Cloud of Unknowing – an anonymous work of Christian mysticism written in Middle English in the latter half of the 14th century – advocates a mystic relationship with God. The text describes a spiritual union with God through the heart. The author of the text advocates centering prayer, a form of inner silence. According to the text, God can not be known through knowledge or from intellection. It is only by emptying the mind of all created images and thoughts that we can arrive to experience God. Continuing on this line of thought, God is completely unknowable by the mind. God is not known through the intellect but through intense contemplation, motivated by love, and stripped of all thought.^[232]

Thomism, though not non-dual in the ordinary sense, considers the unity of God so absolute that even the duality of subject and predicate, to describe him, can be true only by analogy. In Thomist thought, even the Tetragrammaton is only an approximate name, since "I am" involves a predicate whose own essence is its subject.^[233]

The former nun and contemplative Bernadette Roberts is considered a nondualist by Jerry Katz.^[2]

Jewish Hasidism and Kabbalism

According to Jay Michaelson, nonduality begins to appear in the medieval Jewish textual tradition which peaked in Hasidism.^[216] According to Michaelson:

Judaism has within it a strong and very ancient mystical tradition that is deeply nondualistic. "Ein Sof" or infinite nothingness is considered the ground face of all that is. God is considered beyond all proposition or preconception. The physical world is seen as emanating from the nothingness as the many faces "partsufim" of god that are all a part of the sacred nothingness.^[234]

One of the most striking contributions of the Kabbalah, which became a central idea in Chasidic thought, was a highly innovative reading of the monotheistic idea. The belief in "one G-d" is no longer perceived as the mere rejection of other deities or intermediaries, but a denial of any existence outside of G-d.^{[note 29]}

Western esotericism

Western esotericism (also called esotericism and esoterism) is a scholarly term for a wide range of loosely related ideas and movements which have developed within Western society. They are largely distinct both from orthodox Judeo-Christian religion and from Enlightenment rationalism. The earliest traditions which later analysis would label as forms of Western esotericism emerged in the Eastern Mediterranean during Late Antiquity, where Hermetism, Gnosticism, and Neoplatonism developed as schools of thought distinct from what became mainstream Christianity. In Renaissance Europe, interest in many of these older ideas increased, with various intellectuals seeking to combine "pagan" philosophies with the Kabbalah and with Christian philosophy, resulting in the emergence of esoteric movements like Christian theosophy.

Perennial philosophy

The Perennial philosophy has its roots in the Renaissance interest in neo-Platonism and its idea of The One, from which all existence emanates. Marsilio Ficino (1433–1499) sought to integrate Hermeticism with Greek and Jewish-Christian thought,^[235] discerning a Prisca theologia which could be found in all ages.^[236] Giovanni Pico della Mirandola (1463–94) suggested that truth could be found in many, rather than just two, traditions. He proposed a harmony between the thought of Plato and Aristotle, and saw aspects of the Prisca theologia in Averroes, the Koran, the Cabala and other sources.^[237] Agostino Steuco (1497–1548) coined the term philosophia perennis.^[238]

Orientalism

The western world has been exposed to Indian religions since the late 18th century.^[239] The first western translation of a Sanskrit text was made in 1785.^[239] It marked a growing interest in Indian culture and languages.^[240] The first translation of the dualism and nondualism discussing Upanishads appeared in two parts in 1801 and 1802^[241] and influenced Arthur Schopenhauer, who called them "the consolation of my life".^[242] Early translations also appeared in other European languages.^[243]

Transcendentalism and Unitarian Universalism

Transcendentalism was an early 19th-century liberal Protestant movement that developed in the 1830s and 1840s in the Eastern region of the United States. It was rooted in English and German Romanticism, the Biblical criticism of Herder and Schleiermacher, and the skepticism of Hume.^{[web 28]}
The Transcendentalists emphasised an intuitive, experiential approach of religion.^{[web 29]} Following Schleiermacher,^[244] an individual's intuition of truth was taken as the criterion for truth.^{[web 29]} In the late 18th and early 19th century, the first translations of Hindu texts appeared, which were read by the Transcendentalists and influenced their thinking.^{[web 29]} The Transcendentalists also endorsed universalist and Unitarianist ideas, leading to Unitarian Universalism, the idea that there must be truth in other religions as well, since a loving God would redeem all living beings, not just Christians.^{[web 29][web 30]}

Among the transcendentalists' core beliefs was the inherent goodness of both people and nature. Transcendentalists believed that society and its institutions—particularly organized religion and political parties—ultimately corrupted the purity of the individual. They had faith that people are at their best when truly "self-reliant" and independent. It is only from such real individuals that true community could be formed.

The major figures in the movement were Ralph Waldo Emerson, Henry David Thoreau, John Muir, Margaret Fuller and Amos Bronson Alcott.

Neo-Vedanta

Unitarian Universalism had a strong impact on Ram Mohan Roy and the Brahmo Samaj, and subsequently on Swami Vivekananda. Vivekananda was one of the main representatives of Neo-Vedanta, a modern interpretation of Hinduism in line with western esoteric traditions, especially Transcendentalism, New Thought and Theosophy.^[245] His reinterpretation was, and is, very successful, creating a new understanding and appreciation of Hinduism within and outside India,^[245] and was the principal reason for the enthusiastic reception of yoga, transcendental meditation and other forms of Indian spiritual self-improvement in the West.^[246]

Narendranath Datta (Swami Vivekananda) became a member of a Freemasonry lodge "at some point before 1884"^[247] and of the Sadharan Brahmo Samaj in his twenties, a breakaway faction of the Brahmo Samaj led by Keshab Chandra Sen and Debendranath Tagore.^[248] Ram Mohan Roy (1772-1833), the founder of the Brahmo Samaj, had a strong sympathy for the Unitarians,^[249] who were closely connected to the Transcendentalists, who in turn were interested in and influenced by Indian religions early on.^[250] It was in this cultic^[251] milieu that Narendra became acquainted with Western esotericism.^[252] Debendranath Tagore brought this "neo-Hinduism" closer in line with western esotericism, a development which was furthered by Keshubchandra Sen,^[253] who was also influenced by transcendentalism, which emphasised personal religious experience over mere reasoning and theology.^[254] Sen's influence brought Vivekananda fully into contact with western esotericism, and it was also via Sen that he met Ramakrishna.^[255]

Vivekananda's acquaintance with western esotericism made him very successful in western esoteric circles, beginning with his speech in 1893 at the Parliament of Religions. Vivekananda adapted traditional Hindu ideas and religiosity to suit the needs and understandings of his western audiences, who were especially attracted by and familiar with western esoteric traditions and movements like Transcendentalism and New thought.^[256]

In 1897 he founded the Ramakrishna Mission, which was instrumental in the spread of Neo-Vedanta in the west, and attracted people like Alan Watts. Aldous Huxley, author of The Perennial Philosophy, was associated with another neo-Vedanta organisation, the Vedanta Society of Southern California, founded and headed by Swami Prabhavananda. Together with Gerald Heard, Christopher Isherwood, and other followers he was initiated by the Swami and was taught meditation and spiritual practices.^[257]

Theosophical Society

A major force in the mutual influence of eastern and western ideas and religiosity was the Theosophical Society.^[258][259] It searched for ancient wisdom in the east, spreading eastern religious ideas in the west.^[260] One of its salient features was the belief in "Masters of Wisdom",^{[261][note 30]} "beings, human or once human, who have transcended the normal frontiers of knowledge, and who make their wisdom available to others".^[261] The Theosophical Society also spread western ideas in the east, aiding a modernisation of eastern traditions, and contributing to a growing nationalism in the Asian colonies.^{[212][note 31]}

New Age

The New Age movement is a Western spiritual movement that developed in the second half of the 20th century. Its central precepts have been described as "drawing on both Eastern and Western spiritual and metaphysical traditions and infusing them with influences from self-help and motivational psychology, holistic health, parapsychology, consciousness research and quantum physics".^[266] The New Age aims to create "a spirituality without borders or confining dogmas" that is inclusive and pluralistic.^[267] It holds to "a holistic worldview",^[268] emphasising that the Mind, Body and Spirit are interrelated^[269] and that there is a form of monism and unity throughout the universe.^{[web 31]} It attempts to create "a worldview that includes both science and spirituality"^[270] and embraces a number of forms of mainstream science as well as other forms of science that are considered fringe.^{[citation needed]}

Scholarly debates

Nondual consciousness and mystical experience

Insight (prajna, kensho, satori, gnosis, theoria, illumination), especially enlightenment or the realization of the illusory nature of the autonomous "I" or self, is a key element in modern western nondual thought. It is the personal realization that ultimate reality is nondual, and is thought to be a validating means of knowledge of this nondual reality. This insight is interpreted as a psychological state, and labeled as religious or mystical experience.

Development

According to Hori, the notion of "religious experience" can be traced back to William James, who used the term "religious experience" in his book, The Varieties of Religious Experience.^[271] The origins of the use of this term can be dated further back.^[272]

In the 18th, 19th, and 20th centuries, several historical figures put forth very influential views that religion and its beliefs can be grounded in experience itself. While Kant held that moral experience justified religious beliefs, John Wesley in addition to stressing individual moral exertion thought that the religious experiences in the Methodist movement (paralleling the Romantic Movement) were foundational to religious commitment as a way of life.^[273]

Wayne Proudfoot traces the roots of the notion of "religious experience" to the German theologian Friedrich Schleiermacher (1768–1834), who argued that religion is based on a feeling of the infinite. The notion of "religious experience" was used by Schleiermacher and Albert Ritschl to defend religion against the growing scientific and secular critique, and defend the view that human (moral and religious) experience justifies religious beliefs.^[272]

Such religious empiricism would be later seen as highly problematic and was – during the period in-between world wars – famously rejected by Karl Barth.^[274] In the 20th century, religious as well as moral experience as justification for religious beliefs still holds sway. Some influential modern scholars holding this liberal theological view are Charles Raven and the Oxford physicist/theologian Charles Coulson.^[275]

The notion of "religious experience" was adopted by many scholars of religion, of which William James was the most influential.^{[276][note 32]}

Criticism

The notion of "experience" has been criticised.^{[280][281][282]} Robert Sharf points out that "experience" is a typical Western term, which has found its way into Asian religiosity via western influences.^{[280][note 33]}

Insight is not the "experience" of some transcendental reality, but is a cognitive event, the (intuitive) understanding or "grasping" of some specific understanding of reality, as in kensho^[284] or anubhava.^[285]

"Pure experience" does not exist; all experience is mediated by intellectual and cognitive activity.^[286][287] A pure consciousness without concepts, reached by "cleaning the doors of perception",^{[note 34]} would be an overwhelming chaos of sensory input without coherence.^[288]

Nondual consciousness as common essence

Common essence

A main modern proponent of perennialism was Aldous Huxley, who was influenced by Vivekanda's Neo-Vedanta and Universalism.^[257] This popular approach finds supports in the "common-core thesis". According to the "common-core thesis",^[289] different descriptions can mask quite similar if not identical experiences:^[290]

According to Elias Amidon there is an "indescribable, but definitely recognizable, reality that is the ground of all being."^[291] According to Renard, these are based on an experience or intuition of "the Real".^[292] According to Amidon, this reality is signified by "many names" from "spiritual traditions throughout the world":^[291]

[N]ondual awareness, pure awareness, open awareness, presence-awareness, unconditioned mind, rigpa, primordial experience, This, the basic state, the sublime, buddhanature, original nature, spontaneous presence, the oneness of being, the ground of being, the Real, clarity, God-consciousness, divine light, the clear light, illumination, realization and enlightenment.^[291]

According to Renard, nondualism as common essence prefers the term "nondualism", instead of monism, because this understanding is "nonconceptual", "not graspapable in an idea".^{[292][note 35]} Even to call this "ground of reality", "One", or "Oneness" is attributing a characteristic to that ground of reality. The only thing that can be said is that it is "not two" or "non-dual":^{[web 33][293]} According to Renard, Alan Watts has been one of the main contributors to the popularisation of the non-monistic understanding of "nondualism".^{[292][note 36]}

Criticism

The "common-core thesis" is criticised by "diversity theorists" such as S.T Katz and W. Proudfoot.^[290] They argue that

[N]o unmediated experience is possible, and that in the extreme, language is not simply used to interpret experience but in fact constitutes experience.^[290]

The idea of a common essence has been questioned by Yandell, who discerns various "religious experiences" and their corresponding doctrinal settings, which differ in structure and phenomenological content, and in the "evidential value" they present.^[295] Yandell discerns five sorts:^[296]

1. Numinous experiences – Monotheism (Jewish, Christian, Vedantic)^[297]
2. Nirvanic experiences – Buddhism,^[298] "according to which one sees that the self is but a bundle of fleeting states"^[299]
3. Kevala experiences^[300] – Jainism,^[301] "according to which one sees the self as an indestructible subject of experience"^[301]
4. Moksha experiences^[302] – Hinduism,^[301] Brahman "either as a cosmic person, or, quite differently, as qualityless"^[301]
5. Nature mystical experience^[300]

The specific teachings and practices of a specific tradition may determine what "experience" someone has, which means that this "experience" is not the proof of the teaching, but a result of the teaching.^[303] The notion of what exactly constitutes "liberating insight" varies between the various traditions, and even within the traditions. Bronkhorst for example notices that the conception of what exactly "liberating insight" is in Buddhism was developed over time. Whereas originally it may not have been specified, later on the Four Truths served as such, to be superseded by pratityasamutpada, and still later, in the Hinayana schools, by the doctrine of the non-existence of a substantial self or person.^[304] And Schmithausen notices that still other descriptions of this "liberating insight" exist in the Buddhist canon.

Mount Fuji

by Mark Cartwright
published on 12 April 2017 

Original link:  https://www.ancient.eu/Mount_Fuji/ 

Mt. Fuji (Fujisan) is the tallest mountain in Japan and, with its classically symmetrical snow-capped cone, has long been the symbol of that country. The volcano is regarded as a sacred kami or spirit in the Shinto religion, specifically that of Princess Konohanasakuya-hime (aka Fuji-hime or Sengen), and climbing its slopes is considered an act of pilgrimage for followers of that faith. The mountain also has several important sacred shrines, caves, springs and a waterfall. As of 2013 CE Mt. Fuji is a UNESCO World Heritage Site.

Geography

Mt. Fuji, although generally envisaged as a single mountain, actually consists of three distinct volcanoes. Its classic symmetrical slopes are made all the more impressive by the mountain's isolation from any other peaks. Located on Honshu island and straddling the border between the Shizuoka and Yamanashi prefectures, Mt. Fuji is just 100 kilometres (60 miles) from Tokyo and can be seen from its tower blocks on a clear day. The mountain rises to a height of 3,776 metres (12,389 ft) and incorporates five lakes. The volcano is currently dormant with its last eruption occurring in 1708 CE, although between that date and 781 CE there were 17 eruptions recorded.

A Sacred Mountain

Considered sacred by the Ainu people, the indigenous inhabitants of ancient Japan, Mt. Fuji's name may derive from Fuchi, the Ainu god of fire and the hearth. Some Buddhist sects considered the mountain a holy place, and from the 12th century CE, it became a destination for those practising asceticism (shugendo) and seeking a 'rebirth' from their time on the mountain, in a mix of Buddhist, Taoist, and animist beliefs.

In the 15th century CE, a mythology developed which associated Mt. Fuji with Konohanasakuya-hime, the beautiful 'Flower-blossom Princess.' 

However, it is in the Shinto religion that Mt. Fuji holds a particularly special position. Eight major shrines were built around the foot of the mountain and hundreds of smaller ones have since been added. The most important Shinto shrine is the Fujisan Hongu Sengen Taisha which was first constructed in 806 CE, although by tradition, it was originally founded during the reign of Emperor Suinin (29 BCE - 70 CE) at another location at the foot of the mountain. The shrine's current building, with its unusual two storeys, dates to 1604 CE and the site is famous for its 500 cherry trees which blossom each April.

The Kawaguchi Asama Shrine was built in the 9th century CE in an effort to appease the anger of Fujisan after the eruptions of that century. In 1149 CE the Dainichiji temple was built near the peak by Matsudai Shonin where there is also a torii or sacred gate. Unlike most Shinto shrines, there is no honden building containing the goshintai, the sacred physical object which is the embodiment of the shrine's kami, as the mountain itself is regarded as that embodiment. There is also the shrine of Kitaguchi Hongu Fuji Sengen Jinja which was founded during the reign of Emperor Keiko (71-130 CE) but rebuilt in 1718 CE following the eruption eleven years earlier. It is one of the preferred starting points to reach the top, and its torii is over 18 metres (60 ft.) high, making it the largest in Japan. It is likely to keep that record as it is rebuilt every 60 years, each time a little taller than its predecessor.

Fujisan Hongu Sengen Taisha

Climbing the mountain was and still is regarded as an important pilgrimage, an act which became popular from the 15th century CE even for those with no particular religious affiliation. Being a holy site, though, climbers had to be accompanied by a monk or priest guide (Oshi). Prior to 1945 CE women, considered in Shinto to be a source of impurity (kegare), were not permitted to climb the sacred mountain. There are five ascent routes with a total of ten stations. The climb, usually undertaken in July or August when the snow has melted from the peak, takes anywhere from 4 to 8 hours. Some 400,000 people make the effort each year, a good many of them doing so at night in order to catch the auspicious sunrise while at the peak.

Sometime in the 15th century CE, a mythology developed which associated Mt. Fuji with Konohanasakuya-hime, a princess renowned for her beauty whose name translates as 'Flower-blossom Princess.' According to the Kojiki ('Record of Ancient Things' compiled in 712 CE), the princess, daughter of the mountain god Oyamatsumi no kami, descended to earth and became the wife of Ninigi no mikoto, grandson of the sun goddess Amaterasu and founder of Japan's imperial line. Konohanasakuya-hime became the goddess of Mt. Fuji. There are two lava caves formed by ancient trees being covered in a lava flow and then decomposing. Here adherents to the cult of Konohanasakuya-hime, known to Buddhists as Sengen, go through a ritual of 'rebirth.'

Mount Fuji

In the 17th century CE, Hasegawa Kakugyo founded a sect based on Mt. Fuji as the divine source of all life, which was popular in the 18th century CE and necessitated the building of 86 lodges. Kakugyo claimed he had seen the spirit of the mountain in a vision while he was practising asceticism in a cave on Fuji's slopes. Other sacred sites on the mountain include the Oshino Hakkai Springs which have an underground river as their source and the curved Shiraito Falls which are fed by the mountain's annual snowmelt.

Mt. Fuji is also believed to be a gathering point for the spirits of deceased ancestors, and prayers are offered to them as well as (prudently) safety from volcanic eruption, fire, and childbirth (a specific role of Konohanasakuya-hime). Even today, a dream in which Mt. Fuji appears is considered a sign of coming good fortune. Finally, the mountain not only has its own shrines but there are over 13,000 shrines spread across Japan which are dedicated to Fujisan. Many of these include small-scale replicas of the mountain which worshippers who are unable to climb the real thing ascend in symbolic pilgrimage.

Beneath the Wave off Kanagawa

Mt. Fuji in the Arts

Mt. Fuji has long captured the imagination of writers and artists. The 8th-century CE poetry anthology Manyoshu has several poems dedicated to the mountain; it appears smoking at the end of the c. 909 CE  'Tale of the Bamboo Cutter' (Taketori Monogatari), the oldest surviving work of Japanese fiction, and it is the setting of many medieval folktales. The mountain features in several of the haiku poems by Matsuo Basho (1644-1694 CE) too.

In the land of Yamato,
It is our treasure, our tutelary god.
It never tires our eyes to look up
To the lofty peak of Mount Fuji
Manyoshu (Dougill, 17)

More recently, Fuji was famously captured in the ukiyo-e woodblock prints of the noted artist Katsushika Hokusai (1760-1849 CE) who produced a series known as the 'Thirty-Six Views of Mount Fuji' (Fugaku Sanjurokkei). One of the set, Beneath the Wave off Kanagawa, is perhaps the most famous of all Japanese artworks. The artist Utagawa Hiroshige (1797-1858 CE) was even more enraptured and produced an even bigger set of prints, his 'One Hundred Views of Mount Fuji' (Fuji Sanjurokkei) as well as his 'Fifty-Three Stations of the Tokaido Road' (Tokaido Gojusantsugi). The mountain also appears on the current 1000 Yen banknote.

This article was made possible with generous support from the Great Britain Sasakawa Foundation.

 

Editorial Review This Article has been reviewed for accuracy, reliability and adherence to academic standards prior to publication.

About the Author

Mark Cartwright

Mark is a history writer based in Italy. Surrounded by archaeological sites, his special interests include ancient ceramics, architecture, and mythology. He holds an MA in Political Philosophy and is the Publishing Director at AHE.

When AI improves human performance instead of taking over

May 22, 2017
Original link:  http://www.kurzweilai.net/when-ai-improves-human-performance-instead-of-taking-over

The game results show that placing slightly “noisy” bots in a central location (high-degree nodes) improves human coordination by reducing same-color neighbor nodes (the goal of the game). Square nodes show the bots and round nodes show human players; thick red lines show color conflicts, which are reduced with bot participation (right). (credit: Hirokazu Shirado and Nicholas A. Christakis/Nature)

It’s not about artificial intelligence (AI) taking over — it’s about AI improving human performance, a new study by Yale University researchers has shown.

“Much of the current conversation about artificial intelligence has to do with whether AI is a substitute for human beings. We believe the conversation should be about AI as a complement to human beings,” said Nicholas Christakis, Yale University co-director of the Yale Institute for Network Science (YINS) and senior author of a study by Yale Institute for Network Science.*

AI doesn’t even have to be super-sophisticated to make a difference in people’s lives; even “dumb AI” can help human groups, based on the study, which appears in the May 18, 2017 edition of the journal Nature.

How bots can boost human performance

In a series of experiments using teams of human players and autonomous software agents (“bots”), the bots boosted the performance of human groups and the individual players, the researchers found.

The experiment design involved an online color-coordination game that required groups of people to coordinate their actions for a collective goal. The collective goal was for every node to have a color different than all of its neighbor nodes. The subjects were paid a US$2 show-up fee and a declining bonus of up to US$3 depending on the speed of reaching a global solution to the coordination problem (in which every player in a group had chosen a different color from their connected neighbors). When they did not reach a global solution within 5 min, the game was stopped and the subjects earned no bonus.

The human players also interacted with anonymous bots that were programmed with three levels of behavioral randomness — meaning the AI bots sometimes deliberately made mistakes (introduced “noise”). In addition, sometimes the bots were placed in different parts of the social network to try different strategies.

The result: The bots reduced the median time for groups to solve problems by 55.6%. The experiment also showed a cascade effect: People whose performance improved when working with the bots then influenced other human players to raise their game. More than 4,000 people participated in the experiment, which used Yale-developed software called breadboard.

The findings have implications for a variety of situations in which people interact with AI technology, according to the researchers. Examples include human drivers who share roadways with autonomous cars and operations in which human soldiers work in tandem with AI.

“There are many ways in which the future is going to be like this,” Christakis said. “The bots can help humans to help themselves.”

Practical business AI tools

One example: Salesforce CEO Marc Benioff uses a bot called Einstein to help him run his company, Business Intelligence reported Thursday (May 18, 2017).

“Powered by advanced machine learning, deep learning, predictive analytics, natural language processing and smart data discovery, Einstein’s models will be automatically customised for every single customer,” according to the Salesforce blog. “It will learn, self-tune and get smarter with every interaction and additional piece of data. And most importantly, Einstein’s intelligence will be embedded within the context of business, automatically discovering relevant insights, predicting future behavior, proactively recommending best next actions and even automating tasks.”

Benioff says he also uses a version called Einstein Guidance for forecasting and modeling. It even helps end internal politics at executive meetings, calling out under-performing executives.

“AI is the next platform. All future apps for all companies will be built on AI,” Benioff predicts.

* Christakis is a professor of sociology, ecology & evolutionary biology, biomedical engineering, and medicine at Yale. Grants from the Robert Wood Johnson Foundation and the National Institute of Social Sciences supported the research.

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Abstract of Locally noisy autonomous agents improve global human coordination in network experiments

Coordination in groups faces a sub-optimization problem and theory suggests that some randomness may help to achieve global optima. Here we performed experiments involving a networked colour coordination game in which groups of humans interacted with autonomous software agents (known as bots). Subjects (n = 4,000) were embedded in networks (n = 230) of 20 nodes, to which we sometimes added 3 bots. The bots were programmed with varying levels of behavioural randomness and different geodesic locations. We show that bots acting with small levels of random noise and placed in central locations meaningfully improve the collective performance of human groups, accelerating the median solution time by 55.6%. This is especially the case when the coordination problem is hard. Behavioural randomness worked not only by making the task of humans to whom the bots were connected easier, but also by affecting the gameplay of the humans among themselves and hence creating further cascades of benefit in global coordination in these heterogeneous systems.

References:

• Hirokazu Shirado, Nicholas A. Christakis. Locally noisy autonomous agents improve global human coordination in network experiments. Nature, 2017; 545 (7654): 370 DOI: 10.1038/nature22332

How Cues Drive Our Behavior

Neuroscience NewsAugust 3, 2018

Original link:  https://neurosciencenews.com/behavior-cues-dopamine-9654/

University of Minnesota Medical School”How Cues Drive Our Behavior.” NeuroscienceNews. NeuroscienceNews, 3 August 2018.

Summary: Researchers shed light on the role dopamine neurons play in assigning values to transient environmental cues that drive behaviors.

Source: University of Minnesota Medical School.

Do dopamine neurons have a role in causing cues in our environment to acquire value? And, if so, do different groups of dopamine neurons serve different functions within this process?

Those are the questions researchers at the University of Minnesota Medical School are looking to answer.

Recent research published in Nature Neuroscience by University of Minnesota Medical School neuroscientist Benjamin Saunders, PhD, uses a Pavlovian model of conditioning to see if turning on a light – a simple cue – just before dopamine neurons were activated could motivate action. The classic Pavlov model combined the ringing of a bell with providing a tasty steak to a dog that, over time, conditioned a dog to drool when the bell rang with or without a steak. In this research, however, there was no “real” reward like food or water, in order to allow researchers to isolate the function of dopamine neuron activity.

“We wanted to know if dopamine neurons are actually directly responsible for assigning a value to these transient environmental cues, like signs,” said Saunders, who conducted some of his research as a postdoctoral fellow in the laboratory of Patricia Janak, PhD, at Johns Hopkins University.

Dopamine neurons, those cells in the brain that turn on when experiencing a reward. They are also the neurons that degenerate in Parkinson’s disease.

“We learned that dopamine neurons are one way our brains give the cues around us meaning,” said Saunders. “The activity of dopamine neurons alone – even in the absence of food, drugs, or other innately rewarding substances – can imbue cues with value, giving them the ability to motivate actions.”

To answer the second core question, the researchers targeted specific segments of dopamine neurons – those located in the substantial nigra (SNc) and those located in the ventral tegmental area (VTA). These two types of neurons have historically been studied in different disease research fields – SNc neurons in Parkinson’s disease, and VTA neurons in addiction studies.

Scientists learned that cues predicting activation of the two types of neurons drove very different responses – those predicting the SNc neurons led to a sort of “get up and go” response of invigorated rapid movement. The cue predicting VTA neuron activation, however, became enticing on it own, driving approach to the cue’s location, a sort of “where do I go?” response.

To answer the second core question, the researchers targeted specific segments of dopamine neurons – those located in the substantial nigra (SNc) and those located in the ventral tegmental area (VTA). These two types of neurons have historically been studied in different disease research fields – SNc neurons in Parkinson’s disease, and VTA neurons in addiction studies.NeuroscienceNews.com image is in the public domain.

“Our results reveal parallel motivational roles for dopamine neurons in response to cues. In a real world situation, both forms of motivation are critical,” said Saunders. “You have to be motivated to move around and behave, and you have to be motivated to go to the specific location of things you want and need.”

These results provide important understanding of the function of dopamine neurons related to motivations triggered by environmental cues. And this work contributes to the understanding of relapse for those struggling with addictions.

“If a cue – a sign, an alley, a favorite bar – takes on this powerful motivational value, they will be difficult to resist triggers for relapse,” said Saunders. “We know dopamine is involved, but an essential goal for future studies is to understand how normal, healthy cue-triggered motivation differs from dysfunctional motivation that occurs in humans with addiction and related diseases.”

 

About this neuroscience research article

Source: Krystle Barbour – University of Minnesota Medical School
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Dopamine neurons create Pavlovian conditioned stimuli with circuit-defined motivational properties” by Benjamin T. Saunders, Jocelyn M. Richard, Elyssa B. Margolis & Patricia H. Janak in Nature Neuroscience. Published July 23 2018.
doi:10.1038/s41593-018-0191-4

 

---

Abstract

Dopamine neurons create Pavlovian conditioned stimuli with circuit-defined motivational properties

Environmental cues, through Pavlovian learning, become conditioned stimuli that guide animals toward the acquisition of rewards (for example, food) that are necessary for survival. We tested the fundamental role of midbrain dopamine neurons in conferring predictive and motivational properties to cues, independent of external rewards. We found that brief phasic optogenetic excitation of dopamine neurons, when presented in temporal association with discrete sensory cues, was sufficient to instantiate those cues as conditioned stimuli that subsequently both evoked dopamine neuron activity on their own and elicited cue-locked conditioned behavior. Notably, we identified highly parcellated functions for dopamine neuron subpopulations projecting to different regions of striatum, revealing dissociable dopamine systems for the generation of incentive value and conditioned movement invigoration. Our results indicate that dopamine neurons orchestrate Pavlovian conditioning via functionally heterogeneous, circuit-specific motivational signals to create, gate, and shape cue-controlled behaviors.

Empiricism

From Wikipedia, the free encyclopedia

John Locke (1632–1704), a leading philosopher of British empiricism

In philosophy, empiricism is a theory that states that knowledge comes only or primarily from sensory experience. It is one of several views of epistemology, the study of human knowledge, along with rationalism and skepticism. Empiricism emphasises the role of empirical evidence in the formation of ideas, over the idea of innate ideas or traditions. However, empiricists may argue that traditions (or customs) arise due to relations of previous sense experiences.

Empiricism in the philosophy of science emphasises evidence, especially as discovered in experiments. It is a fundamental part of the scientific method that all hypotheses and theories must be tested against observations of the natural world rather than resting solely on a priori reasoning, intuition, or revelation.

Empiricism, often used by natural scientists, says that "knowledge is based on experience" and that "knowledge is tentative and probabilistic, subject to continued revision and falsification".^[4] Empirical research, including experiments and validated measurement tools, guides the scientific method.

Etymology

The English term empirical derives from the Ancient Greek word ἐμπειρία, empeiria, which is cognate with and translates to the Latin experientia, from which are derived the word experience and the related experiment.

History

Background

A central concept in science and the scientific method is that it must be empirically based on the evidence of the senses. Both natural and social sciences use working hypotheses that are testable by observation and experiment. The term semi-empirical is sometimes used to describe theoretical methods that make use of basic axioms, established scientific laws, and previous experimental results in order to engage in reasoned model building and theoretical inquiry.
Philosophical empiricists hold no knowledge to be properly inferred or deduced unless it is derived from one's sense-based experience.^[5] This view is commonly contrasted with rationalism, which states that knowledge may be derived from reason independently of the senses. For example, John Locke held that some knowledge (e.g. knowledge of God's existence) could be arrived at through intuition and reasoning alone. Similarly Robert Boyle, a prominent advocate of the experimental method, held that we have innate ideas.^[6][7] The main continental rationalists (Descartes, Spinoza, and Leibniz) were also advocates of the empirical "scientific method".^[8][9]

Early empiricism

Vaisheshika darsana, founded by the ancient Indian philosopher Kanada, accepted perception and inference as the only two reliable sources of knowledge. This is enumerated in his work Vaiśeṣika Sūtra.

The earliest Western proto-empiricists were the Empiric school of ancient Greek medical practitioners, who rejected the three doctrines of the Dogmatic school, preferring to rely on the observation of "phenomena".^[10]

The notion of tabula rasa ("clean slate" or "blank tablet") connotes a view of mind as an originally blank or empty recorder (Locke used the words "white paper") on which experience leaves marks. This denies that humans have innate ideas. The image dates back to Aristotle:

What the mind (nous) thinks must be in it in the same sense as letters are on a tablet (grammateion) which bears no actual writing (grammenon); this is just what happens in the case of the mind. (Aristotle, On the Soul, 3.4.430^a1).

Aristotle's explanation of how this was possible was not strictly empiricist in a modern sense, but rather based on his theory of potentiality and actuality, and experience of sense perceptions still requires the help of the active nous. These notions contrasted with Platonic notions of the human mind as an entity that pre-existed somewhere in the heavens, before being sent down to join a body on Earth (see Plato's Phaedo and Apology, as well as others). Aristotle was considered to give a more important position to sense perception than Plato, and commentators in the Middle Ages summarized one of his positions as "nihil in intellectu nisi prius fuerit in sensu" (Latin for "nothing in the intellect without first being in the senses").

This idea was later developed in ancient philosophy by the Stoic school. Stoic epistemology generally emphasized that the mind starts blank, but acquires knowledge as the outside world is impressed upon it.^[11] The doxographer Aetius summarizes this view as "When a man is born, the Stoics say, he has the commanding part of his soul like a sheet of paper ready for writing upon."^[12]
 

A drawing of Ibn Sina (Avicenna) from 1271

During the Middle Ages Aristotle's theory of tabula rasa was developed by Islamic philosophers starting with Al Farabi, developing into an elaborate theory by Avicenna^[13] and demonstrated as a thought experiment by Ibn Tufail.^[14] For Avicenna (Ibn Sina), for example, the tabula rasa is a pure potentiality that is actualized through education, and knowledge is attained through "empirical familiarity with objects in this world from which one abstracts universal concepts" developed through a "syllogistic method of reasoning in which observations lead to propositional statements which when compounded lead to further abstract concepts". The intellect itself develops from a material intellect (al-'aql al-hayulani), which is a potentiality "that can acquire knowledge to the active intellect (al-'aql al-fa'il), the state of the human intellect in conjunction with the perfect source of knowledge".^[13] So the immaterial "active intellect", separate from any individual person, is still essential for understanding to occur.

In the 12th century CE the Andalusian Muslim philosopher and novelist Abu Bakr Ibn Tufail (known as "Abubacer" or "Ebn Tophail" in the West) included the theory of tabula rasa as a thought experiment in his Arabic philosophical novel, Hayy ibn Yaqdhan in which he depicted the development of the mind of a feral child "from a tabula rasa to that of an adult, in complete isolation from society" on a desert island, through experience alone. The Latin translation of his philosophical novel, entitled Philosophus Autodidactus, published by Edward Pococke the Younger in 1671, had an influence on John Locke's formulation of tabula rasa in An Essay Concerning Human Understanding.^[14]

A similar Islamic theological novel, Theologus Autodidactus, was written by the Arab theologian and physician Ibn al-Nafis in the 13th century. It also dealt with the theme of empiricism through the story of a feral child on a desert island, but departed from its predecessor by depicting the development of the protagonist's mind through contact with society rather than in isolation from society.^[15]

During the 13th century Thomas Aquinas adopted the Aristotelian position that the senses are essential to mind into scholasticism. Bonaventure (1221–1274), one of Aquinas' strongest intellectual opponents, offered some of the strongest arguments in favour of the Platonic idea of the mind.

Renaissance Italy

In the late renaissance various writers began to question the medieval and classical understanding of knowledge acquisition in a more fundamental way. In political and historical writing Niccolò Machiavelli and his friend Francesco Guicciardini initiated a new realistic style of writing. Machiavelli in particular was scornful of writers on politics who judged everything in comparison to mental ideals and demanded that people should study the "effectual truth" instead. Their contemporary, Leonardo da Vinci (1452–1519) said, "If you find from your own experience that something is a fact and it contradicts what some authority has written down, then you must abandon the authority and base your reasoning on your own findings."^[16]

The decidedly anti-Aristotelian and anti-clerical music theorist Vincenzo Galilei (c. 1520 – 1591), father of Galileo and the inventor of monody, made use of the method in successfully solving musical problems, firstly, of tuning such as the relationship of pitch to string tension and mass in stringed instruments, and to volume of air in wind instruments; and secondly to composition, by his various suggestions to composers in his Dialogo della musica antica e moderna (Florence, 1581). The Italian word he used for "experiment" was esperienza. It is known that he was the essential pedagogical influence upon the young Galileo, his eldest son (cf. Coelho, ed. Music and Science in the Age of Galileo Galilei), arguably one of the most influential empiricists in history. Vincenzo, through his tuning research, found the underlying truth at the heart of the misunderstood myth of 'Pythagoras' hammers' (the square of the numbers concerned yielded those musical intervals, not the actual numbers, as believed), and through this and other discoveries that demonstrated the fallibility of traditional authorities, a radically empirical attitude developed, passed on to Galileo, which regarded "experience and demonstration" as the sine qua non of valid rational enquiry.

British empiricism

British empiricism, though it was not a term used at the time, derives from the 17th century period of early modern philosophy and modern science. The term became useful in order to describe differences perceived between two of its founders Francis Bacon, described as empiricist, and René Descartes, who is described as a rationalist. Thomas Hobbes and Baruch Spinoza, in the next generation, are often also described as an empiricist and a rationalist respectively. John Locke, George Berkeley, and David Hume were the primary exponents of empiricism in the 18th century Enlightenment, with Locke being the person who is normally known as the founder of empiricism as such.

In response to the early-to-mid-17th century "continental rationalism" John Locke (1632–1704) proposed in An Essay Concerning Human Understanding (1689) a very influential view wherein the only knowledge humans can have is a posteriori, i.e., based upon experience. Locke is famously attributed with holding the proposition that the human mind is a tabula rasa, a "blank tablet", in Locke's words "white paper", on which the experiences derived from sense impressions as a person's life proceeds are written. There are two sources of our ideas: sensation and reflection. In both cases, a distinction is made between simple and complex ideas. The former are unanalysable, and are broken down into primary and secondary qualities. Primary qualities are essential for the object in question to be what it is. Without specific primary qualities, an object would not be what it is. For example, an apple is an apple because of the arrangement of its atomic structure. If an apple was structured differently, it would cease to be an apple. Secondary qualities are the sensory information we can perceive from its primary qualities. For example, an apple can be perceived in various colours, sizes, and textures but it is still identified as an apple. Therefore, its primary qualities dictate what the object essentially is, while its secondary qualities define its attributes. Complex ideas combine simple ones, and divide into substances, modes, and relations. According to Locke, our knowledge of things is a perception of ideas that are in accordance or discordance with each other, which is very different from the quest for certainty of Descartes.

Bishop George Berkeley

A generation later, the Irish Anglican bishop, George Berkeley (1685–1753), determined that Locke's view immediately opened a door that would lead to eventual atheism. In response to Locke, he put forth in his Treatise Concerning the Principles of Human Knowledge (1710) an important challenge to empiricism in which things only exist either as a result of their being perceived, or by virtue of the fact that they are an entity doing the perceiving. (For Berkeley, God fills in for humans by doing the perceiving whenever humans are not around to do it.) In his text Alciphron, Berkeley maintained that any order humans may see in nature is the language or handwriting of God.^[17] Berkeley's approach to empiricism would later come to be called subjective idealism.^[18][19]

The Scottish philosopher David Hume (1711–1776) responded to Berkeley's criticisms of Locke, as well as other differences between early modern philosophers, and moved empiricism to a new level of skepticism. Hume argued in keeping with the empiricist view that all knowledge derives from sense experience, but he accepted that this has implications not normally acceptable to philosophers. He wrote for example, "Locke divides all arguments into demonstrative and probable. On this view, we must say that it is only probable that all men must die or that the sun will rise to-morrow, because neither of these can be demonstrated. But to conform our language more to common use, we ought to divide arguments into demonstrations, proofs, and probabilities—by ‘proofs’ meaning arguments from experience that leave no room for doubt or opposition."^[20] And,^[21]

"I believe the most general and most popular explication of this matter, is to say [See Mr. Locke, chapter of power.], that finding from experience, that there are several new productions in matter, such as the motions and variations of body, and concluding that there must somewhere be a power capable of producing them, we arrive at last by this reasoning at the idea of power and efficacy. But to be convinced that this explication is more popular than philosophical, we need but reflect on two very obvious principles. First, That reason alone can never give rise to any original idea, and secondly, that reason, as distinguished from experience, can never make us conclude, that a cause or productive quality is absolutely requisite to every beginning of existence. Both these considerations have been sufficiently explained: and therefore shall not at present be any farther insisted on."

— Hume Section XIV "of the idea of necessary connexion in A Treatise of Human Nature

Hume divided all of human knowledge into two categories: relations of ideas and matters of fact (see also Kant's analytic-synthetic distinction). Mathematical and logical propositions (e.g. "that the square of the hypotenuse is equal to the sum of the squares of the two sides") are examples of the first, while propositions involving some contingent observation of the world (e.g. "the sun rises in the East") are examples of the second. All of people's "ideas", in turn, are derived from their "impressions". For Hume, an "impression" corresponds roughly with what we call a sensation. To remember or to imagine such impressions is to have an "idea". Ideas are therefore the faint copies of sensations.^[22]
 

David Hume's empiricism led to numerous philosophical schools.

Hume maintained that no knowledge, even the most basic beliefs about the natural world, can be conclusively established by reason. Rather, he maintained, our beliefs are more a result of accumulated habits, developed in response to accumulated sense experiences. Among his many arguments Hume also added another important slant to the debate about scientific method—that of the problem of induction. Hume argued that it requires inductive reasoning to arrive at the premises for the principle of inductive reasoning, and therefore the justification for inductive reasoning is a circular argument.^[22] Among Hume's conclusions regarding the problem of induction is that there is no certainty that the future will resemble the past. Thus, as a simple instance posed by Hume, we cannot know with certainty by inductive reasoning that the sun will continue to rise in the East, but instead come to expect it to do so because it has repeatedly done so in the past.^[22]

Hume concluded that such things as belief in an external world and belief in the existence of the self were not rationally justifiable. According to Hume these beliefs were to be accepted nonetheless because of their profound basis in instinct and custom. Hume's lasting legacy, however, was the doubt that his skeptical arguments cast on the legitimacy of inductive reasoning, allowing many skeptics who followed to cast similar doubt.

Phenomenalism

Most of Hume's followers have disagreed with his conclusion that belief in an external world is rationally unjustifiable, contending that Hume's own principles implicitly contained the rational justification for such a belief, that is, beyond being content to let the issue rest on human instinct, custom and habit.^[23] According to an extreme empiricist theory known as phenomenalism, anticipated by the arguments of both Hume and George Berkeley, a physical object is a kind of construction out of our experiences.^[24] Phenomenalism is the view that physical objects, properties, events (whatever is physical) are reducible to mental objects, properties, events. Ultimately, only mental objects, properties, events, exist—hence the closely related term subjective idealism. By the phenomenalistic line of thinking, to have a visual experience of a real physical thing is to have an experience of a certain kind of group of experiences. This type of set of experiences possesses a constancy and coherence that is lacking in the set of experiences of which hallucinations, for example, are a part. As John Stuart Mill put it in the mid-19th century, matter is the "permanent possibility of sensation".^[25] Mill's empiricism went a significant step beyond Hume in still another respect: in maintaining that induction is necessary for all meaningful knowledge including mathematics. As summarized by D.W. Hamlin:

[Mill] claimed that mathematical truths were merely very highly confirmed generalizations from experience; mathematical inference, generally conceived as deductive [and a priori] in nature, Mill set down as founded on induction. Thus, in Mill's philosophy there was no real place for knowledge based on relations of ideas. In his view logical and mathematical necessity is psychological; we are merely unable to conceive any other possibilities than those that logical and mathematical propositions assert. This is perhaps the most extreme version of empiricism known, but it has not found many defenders.^[19]

Mill's empiricism thus held that knowledge of any kind is not from direct experience but an inductive inference from direct experience.^[26] The problems other philosophers have had with Mill's position center around the following issues: Firstly, Mill's formulation encounters difficulty when it describes what direct experience is by differentiating only between actual and possible sensations. This misses some key discussion concerning conditions under which such "groups of permanent possibilities of sensation" might exist in the first place. Berkeley put God in that gap; the phenomenalists, including Mill, essentially left the question unanswered. In the end, lacking an acknowledgement of an aspect of "reality" that goes beyond mere "possibilities of sensation", such a position leads to a version of subjective idealism. Questions of how floor beams continue to support a floor while unobserved, how trees continue to grow while unobserved and untouched by human hands, etc., remain unanswered, and perhaps unanswerable in these terms.^[19][27] Secondly, Mill's formulation leaves open the unsettling possibility that the "gap-filling entities are purely possibilities and not actualities at all".^[27] Thirdly, Mill's position, by calling mathematics merely another species of inductive inference, misapprehends mathematics. It fails to fully consider the structure and method of mathematical science, the products of which are arrived at through an internally consistent deductive set of procedures which do not, either today or at the time Mill wrote, fall under the agreed meaning of induction.^[19][27][28]

The phenomenalist phase of post-Humean empiricism ended by the 1940s, for by that time it had become obvious that statements about physical things could not be translated into statements about actual and possible sense data.^[29] If a physical object statement is to be translatable into a sense-data statement, the former must be at least deducible from the latter. But it came to be realized that there is no finite set of statements about actual and possible sense-data from which we can deduce even a single physical-object statement. The translating or paraphrasing statement must be couched in terms of normal observers in normal conditions of observation. There is, however, no finite set of statements that are couched in purely sensory terms and can express the satisfaction of the condition of the presence of a normal observer. According to phenomenalism, to say that a normal observer is present is to make the hypothetical statement that were a doctor to inspect the observer, the observer would appear to the doctor to be normal. But, of course, the doctor himself must be a normal observer. If we are to specify this doctor's normality in sensory terms, we must make reference to a second doctor who, when inspecting the sense organs of the first doctor, would himself have to have the sense data a normal observer has when inspecting the sense organs of a subject who is a normal observer. And if we are to specify in sensory terms that the second doctor is a normal observer, we must refer to a third doctor, and so on (also see the third man).^[30][31]

Logical empiricism

Logical empiricism (also logical positivism or neopositivism) was an early 20th-century attempt to synthesize the essential ideas of British empiricism (e.g. a strong emphasis on sensory experience as the basis for knowledge) with certain insights from mathematical logic that had been developed by Gottlob Frege and Ludwig Wittgenstein. Some of the key figures in this movement were Otto Neurath, Moritz Schlick and the rest of the Vienna Circle, along with A.J. Ayer, Rudolf Carnap and Hans Reichenbach.
The neopositivists subscribed to a notion of philosophy as the conceptual clarification of the methods, insights and discoveries of the sciences. They saw in the logical symbolism elaborated by Frege (1848–1925) and Bertrand Russell (1872–1970) a powerful instrument that could rationally reconstruct all scientific discourse into an ideal, logically perfect, language that would be free of the ambiguities and deformations of natural language. This gave rise to what they saw as metaphysical pseudoproblems and other conceptual confusions. By combining Frege's thesis that all mathematical truths are logical with the early Wittgenstein's idea that all logical truths are mere linguistic tautologies, they arrived at a twofold classification of all propositions: the analytic (a priori) and the synthetic (a posteriori).^[32] On this basis, they formulated a strong principle of demarcation between sentences that have sense and those that do not: the so-called verification principle. Any sentence that is not purely logical, or is unverifiable is devoid of meaning. As a result, most metaphysical, ethical, aesthetic and other traditional philosophical problems came to be considered pseudoproblems.^[33]

In the extreme empiricism of the neopositivists—at least before the 1930s—any genuinely synthetic assertion must be reducible to an ultimate assertion (or set of ultimate assertions) that expresses direct observations or perceptions. In later years, Carnap and Neurath abandoned this sort of phenomenalism in favor of a rational reconstruction of knowledge into the language of an objective spatio-temporal physics. That is, instead of translating sentences about physical objects into sense-data, such sentences were to be translated into so-called protocol sentences, for example, "X at location Y and at time T observes such and such."^[34] The central theses of logical positivism (verificationism, the analytic–synthetic distinction, reductionism, etc.) came under sharp attack after World War II by thinkers such as Nelson Goodman, W.V. Quine, Hilary Putnam, Karl Popper, and Richard Rorty. By the late 1960s, it had become evident to most philosophers that the movement had pretty much run its course, though its influence is still significant among contemporary analytic philosophers such as Michael Dummett and other anti-realists.

Pragmatism

In the late 19th and early 20th century several forms of pragmatic philosophy arose. The ideas of pragmatism, in its various forms, developed mainly from discussions between Charles Sanders Peirce and William James when both men were at Harvard in the 1870s. James popularized the term "pragmatism", giving Peirce full credit for its patrimony, but Peirce later demurred from the tangents that the movement was taking, and redubbed what he regarded as the original idea with the name of "pragmaticism". Along with its pragmatic theory of truth, this perspective integrates the basic insights of empirical (experience-based) and rational (concept-based) thinking.

Charles Sanders Peirce

Charles Peirce (1839–1914) was highly influential in laying the groundwork for today's empirical scientific method.^[35] Although Peirce severely criticized many elements of Descartes' peculiar brand of rationalism, he did not reject rationalism outright. Indeed, he concurred with the main ideas of rationalism, most importantly the idea that rational concepts can be meaningful and the idea that rational concepts necessarily go beyond the data given by empirical observation. In later years he even emphasized the concept-driven side of the then ongoing debate between strict empiricism and strict rationalism, in part to counterbalance the excesses to which some of his cohorts had taken pragmatism under the "data-driven" strict-empiricist view.

Among Peirce's major contributions was to place inductive reasoning and deductive reasoning in a complementary rather than competitive mode, the latter of which had been the primary trend among the educated since David Hume wrote a century before. To this, Peirce added the concept of abductive reasoning. The combined three forms of reasoning serve as a primary conceptual foundation for the empirically based scientific method today. Peirce's approach "presupposes that (1) the objects of knowledge are real things, (2) the characters (properties) of real things do not depend on our perceptions of them, and (3) everyone who has sufficient experience of real things will agree on the truth about them. According to Peirce's doctrine of fallibilism, the conclusions of science are always tentative. The rationality of the scientific method does not depend on the certainty of its conclusions, but on its self-corrective character: by continued application of the method science can detect and correct its own mistakes, and thus eventually lead to the discovery of truth".^[36]
 

William James

In his Harvard "Lectures on Pragmatism" (1903), Peirce enumerated what he called the "three cotary propositions of pragmatism" (L: cos, cotis whetstone), saying that they "put the edge on the maxim of pragmatism". First among these he listed the peripatetic-thomist observation mentioned above, but he further observed that this link between sensory perception and intellectual conception is a two-way street. That is, it can be taken to say that whatever we find in the intellect is also incipiently in the senses. Hence, if theories are theory-laden then so are the senses, and perception itself can be seen as a species of abductive inference, its difference being that it is beyond control and hence beyond critique—in a word, incorrigible. This in no way conflicts with the fallibility and revisability of scientific concepts, since it is only the immediate percept in its unique individuality or "thisness"—what the Scholastics called its haecceity—that stands beyond control and correction. Scientific concepts, on the other hand, are general in nature, and transient sensations do in another sense find correction within them. This notion of perception as abduction has received periodic revivals in artificial intelligence and cognitive science research, most recently for instance with the work of Irvin Rock on indirect perception.^[37][38]

Around the beginning of the 20th century, William James (1842–1910) coined the term "radical empiricism" to describe an offshoot of his form of pragmatism, which he argued could be dealt with separately from his pragmatism—though in fact the two concepts are intertwined in James's published lectures. James maintained that the empirically observed "directly apprehended universe needs ... no extraneous trans-empirical connective support",^[39] by which he meant to rule out the perception that there can be any value added by seeking supernatural explanations for natural phenomena. James' "radical empiricism" is thus not radical in the context of the term "empiricism", but is instead fairly consistent with the modern use of the term "empirical". His method of argument in arriving at this view, however, still readily encounters debate within philosophy even today.

John Dewey (1859–1952) modified James' pragmatism to form a theory known as instrumentalism. The role of sense experience in Dewey's theory is crucial, in that he saw experience as unified totality of things through which everything else is interrelated. Dewey's basic thought, in accordance with empiricism was that reality is determined by past experience. Therefore, humans adapt their past experiences of things to perform experiments upon and test the pragmatic values of such experience. The value of such experience is measured experientially and scientifically, and the results of such tests generate ideas that serve as instruments for future experimentation,^[40] in physical sciences as in ethics.^[41] Thus, ideas in Dewey's system retain their empiricist flavour in that they are only known a posteriori.

3D-printed ‘bionic skin’ could give robots and prosthetics the sense of touch

Could also be printed directly on human skin for pulse monitoring or as a human-machine interface --- imagine a computer mouse built into your fingertip

May 26, 2017
Original link:  http://www.kurzweilai.net/3d-printed-bionic-skin-could-give-robots-and-prosthetics-the-sense-of-touch

Schematic of a new kind of 3D printer that can print touch sensors directly on a model hand. (credit: Shuang-Zhuang Guo and Michael McAlpine/Advanced Materials )

Engineering researchers at the University of Minnesota have developed a process for 3D-printing stretchable, flexible, and sensitive electronic sensory devices that could give robots or prosthetic hands — or even real skin — the ability to mechanically sense their environment.

One major use would be to give surgeons the ability to feel during minimally invasive surgeries instead of using cameras, or to increase the sensitivity of surgical robots. The process could also make it easier for robots to walk and interact with their environment.

Printing electronics directly on human skin could be used for pulse monitoring, energy harvesting (of movements), detection of finger motions (on a keyboard or other devices), or chemical sensing (for example, by soldiers in the field to detect dangerous chemicals or explosives). Or imagine a future computer mouse built into your fingertip, with haptic touch on any surface.

“While we haven’t printed on human skin yet, we were able to print on the curved surface of a model hand using our technique,” said Michael McAlpine, a University of Minnesota mechanical engineering associate professor and lead researcher on the study.* “We also interfaced a printed device with the skin and were surprised that the device was so sensitive that it could detect your pulse in real time.”

The researchers also visualize use in “bionic organs.”

A unique skin-compatible 3D-printing process

(left) Schematic of the tactile sensor. (center) Top view. (right) Optical image showing the conformally printed 3D tactile sensor on a fingertip. Scale bar = 4 mm. (credit: Shuang-Zhuang Guo et al./Advanced Materials)

McAlpine and his team made the sensing fabric with a one-of-a kind 3D printer they built in the lab. The multifunctional printer has four nozzles to print the various specialized “inks” that make up the layers of the device — a base layer of silicone**, top and bottom electrodes made of a silver-based piezoresistive conducting ink, a coil-shaped pressure sensor, and a supporting layer that holds the top layer in place while it sets (later washed away in the final manufacturing process).

Surprisingly, all of the layers of “inks” used in the flexible sensors can set at room temperature. Conventional 3D printing using liquid plastic is too hot and too rigid to use on the skin. The sensors can stretch up to three times their original size.

The researchers say the next step is to move toward semiconductor inks and printing on a real surface. “The manufacturing is built right into the process, so it is ready to go now,” McAlpine said.

The research was published online in the journal Advanced Materials. It was funded by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health.

* McAlpine integrated electronics and novel 3D-printed nanomaterials to create a “bionic ear” in 2013.

** The silicone rubber has a low modulus of elasticity of 150 kPa, similar to that of skin, and lower hardness (Shore A 10) than that of human skin, according to the Advanced Materials paper.

College of Science and Engineering, UMN | 3D Printed Stretchable Tactile Sensors

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Abstract of 3D Printed Stretchable Tactile Sensors

The development of methods for the 3D printing of multifunctional devices could impact areas ranging from wearable electronics and energy harvesting devices to smart prosthetics and human–machine interfaces. Recently, the development of stretchable electronic devices has accelerated, concomitant with advances in functional materials and fabrication processes. In particular, novel strategies have been developed to enable the intimate biointegration of wearable electronic devices with human skin in ways that bypass the mechanical and thermal restrictions of traditional microfabrication technologies. Here, a multimaterial, multiscale, and multifunctional 3D printing approach is employed to fabricate 3D tactile sensors under ambient conditions conformally onto freeform surfaces. The customized sensor is demonstrated with the capabilities of detecting and differentiating human movements, including pulse monitoring and finger motions. The custom 3D printing of functional materials and devices opens new routes for the biointegration of various sensors in wearable electronics systems, and toward advanced bionic skin applications.

References:

• Shuang-Zhuang Guo, Kaiyan Qiu, Fanben Meng, Sung Hyun Park, Michael C. McAlpine. 3D Printed Stretchable Tactile Sensors. Advanced Materials, 2017; 1701218 DOI: 10.1002/adma.201701218