Turtles all the way down

From Wikipedia, the free encyclopedia

The saying holds that the world is supported by a chain of increasingly large turtles. Beneath each turtle is yet another: it is "turtles all the way down".

"Turtles all the way down" is an expression of the problem of infinite regress. The saying alludes to the mythological idea of a World Turtle that supports the earth on its back. It suggests that this turtle rests on the back of an even larger turtle, which itself is part of a column of increasingly large turtles that continues indefinitely (i.e. "turtles all the way down").

The exact origin of the phrase is uncertain. In the form "rocks all the way down", the saying appears as early as 1838.^[1] References to the saying's mythological antecedents, the World Turtle and its counterpart the World Elephant, were made by a number of authors in the 17th and 18th centuries.^[2][3] This mythology is frequently assumed to have originated in ancient India and other Hinduist beliefs.

The expression has been used to illustrate problems such as the "unmoved mover" paradox in cosmology, the regress argument in epistemology, and more recently, the meta-learner optimizers in machine learning.^[4]

History

Background in Hindu mythology

Four World Elephants resting on a World Turtle

Early variants of the saying do not always have explicit references to infinite regression (i.e., the phrase "all the way down"). They often reference stories featuring a World Elephant, World Turtle, or other similar creatures that are claimed to come from Hindu mythology. The first known reference to a Hindu source is found in a letter by Jesuit Emanual de Veiga (1549–1605), written at Chandagiri on 18 September 1599, in which the relevant passage reads:^[5]

Alii dicebant terram novem constare angulis, quibus cœlo innititur. Alius ab his dissentiens volebat terram septem elephantis fulciri, elephantes uero ne subsiderent, super testudine pedes fixos habere. Quærenti quis testudinis corpus firmaret, ne dilaberetur, respondere nesciuit.

Others hold that the earth has nine corners by which the heavens are supported. Another disagreeing from these would have the earth supported by seven elephants, and the elephants do not sink down because their feet are fixed on a tortoise. When asked who would fix the body of the tortoise, so that it would not collapse, he said that he did not know.

Veiga's account seems to have been received by Samuel Purchas, who has a close paraphrase in his Purchas His Pilgrims (1613/1626), "that the Earth had nine corners, whereby it was borne up by the Heaven. Others dissented, and said, that the Earth was borne up by seven Elephants; the Elephants' feet stood on Tortoises, and they were borne by they know not what."^[6] Purchas' account is again reflected by John Locke in his 1689 tract An Essay Concerning Human Understanding, where Locke introduces the story as a trope referring to the problem of induction in philosophical debate. Locke compares one who would say that properties inhere in "Substance" to the Indian who said the world was on an elephant which was on a tortoise, "But being again pressed to know what gave support to the broad-back'd Tortoise, replied, something, he knew not what".^[2] The story is also referenced by Henry David Thoreau, who writes in his journal entry of 4 May 1852: "Men are making speeches ... all over the country, but each expresses only the thought, or the want of thought, of the multitude. No man stands on truth. They are merely banded together as usual, one leaning on another and all together on nothing; as the Hindoos made the world rest on an elephant, and the elephant on a tortoise, and had nothing to put under the tortoise."^[7]

Modern form

In the form of "rocks all the way down", the saying dates to at least 1838, when it was printed in an unsigned anecdote in the New-York Mirror about a schoolboy and an old woman living in the woods:

"The world, marm," said I, anxious to display my acquired knowledge, "is not exactly round, but resembles in shape a flattened orange; and it turns on its axis once in twenty-four hours."

"Well, I don't know anything about its axes," replied she, "but I know it don't turn round, for if it did we'd be all tumbled off; and as to its being round, any one can see it's a square piece of ground, standing on a rock!"

"Standing on a rock! but upon what does that stand?"

"Why, on another, to be sure!"

"But what supports the last?"

"Lud! child, how stupid you are! There's rocks all the way down!"^[1]

A version of the saying in its "turtle" form appeared in an 1854 transcript of remarks by preacher Joseph Frederick Berg addressed to Joseph Barker:

My opponent's reasoning reminds me of the heathen, who, being asked on what the world stood, replied, "On a tortoise." But on what does the tortoise stand? "On another tortoise." With Mr. Barker, too, there are tortoises all the way down. (Vehement and vociferous applause.)

— "Second Evening: Remarks of Rev. Dr. Berg"^[8]

William James

Many 20th-century attributions claim that William James is the source of the phrase.^[9] James referred to the fable of the elephant and tortoise several times, but told the infinite regress story with "rocks all the way down" in his 1882 essay, "Rationality, Activity and Faith":

Like the old woman in the story who described the world as resting on a rock, and then explained that rock to be supported by another rock, and finally when pushed with questions said it was "rocks all the way down," he who believes this to be a radically moral universe must hold the moral order to rest either on an absolute and ultimate should or on a series of shoulds "all the way down."^[10]

The linguist John R. Ross also associates James with the phrase:

The following anecdote is told of William James. [...] After a lecture on cosmology and the structure of the solar system, James was accosted by a little old lady.

"Your theory that the sun is the centre of the solar system, and the earth is a ball which rotates around it has a very convincing ring to it, Mr. James, but it's wrong. I've got a better theory," said the little old lady.

"And what is that, madam?" inquired James politely.

"That we live on a crust of earth which is on the back of a giant turtle."

Not wishing to demolish this absurd little theory by bringing to bear the masses of scientific evidence he had at his command, James decided to gently dissuade his opponent by making her see some of the inadequacies of her position.

"If your theory is correct, madam," he asked, "what does this turtle stand on?"

"You're a very clever man, Mr. James, and that's a very good question," replied the little old lady, "but I have an answer to it. And it's this: The first turtle stands on the back of a second, far larger, turtle, who stands directly under him."

"But what does this second turtle stand on?" persisted James patiently.

To this, the little old lady crowed triumphantly,

"It's no use, Mr. James — it's turtles all the way down."

— J. R. Ross, Constraints on Variables in Syntax 1967^[11]

In epistemology and other disciplines

The metaphor is used as an example of the problem of infinite regress in epistemology to show that there is a necessary foundation to knowledge, as written by Johann Gottlieb Fichte in 1794:^{[12][page needed]}

"If there is not to be any (system of human knowledge dependent upon an absolute first principle) two cases are only possible. Either there is no immediate certainty at all, and then our knowledge forms many series or one infinite series, wherein each theorem is derived from a higher one, and this again from a higher one, et., etc. We build our houses on the earth, the earth rests on an elephant, the elephant on a tortoise, the tortoise again--who knows on what?-- and so on ad infinitum. True, if our knowledge is thus constituted, we can not alter it; but neither have we, then, any firm knowledge. We may have gone back to a certain link of our series, and have found every thing firm up to this link; but who can guarantee us that, if we go further back, we may not find it ungrounded, and shall thus have to abandon it? Our certainty is only assumed, and we can never be sure of it for a single following day."

David Hume references the story in his Dialogues Concerning Natural Religion when arguing against God as an unmoved mover:^[3]

How, therefore, shall we satisfy ourselves concerning the cause of that Being whom you suppose the Author of Nature, or, according to your system of Anthropomorphism, the ideal world, into which you trace the material? Have we not the same reason to trace that ideal world into another ideal world, or new intelligent principle? But if we stop, and go no further; why go so far? why not stop at the material world? How can we satisfy ourselves without going on in infinitum? And, after all, what satisfaction is there in that infinite progression? Let us remember the story of the Indian philosopher and his elephant. It was never more applicable than to the present subject. If the material world rests upon a similar ideal world, this ideal world must rest upon some other; and so on, without end. It were better, therefore, never to look beyond the present material world. By supposing it to contain the principle of its order within itself, we really assert it to be God; and the sooner we arrive at that Divine Being, so much the better. When you go one step beyond the mundane system, you only excite an inquisitive humour which it is impossible ever to satisfy.

Bertrand Russell also mentions the story in his 1927 lecture Why I Am Not a Christian while discounting the First Cause argument intended to be a proof of God's existence:

If everything must have a cause, then God must have a cause. If there can be anything without a cause, it may just as well be the world as God, so that there cannot be any validity in that argument. It is exactly of the same nature as the Hindu's view, that the world rested upon an elephant and the elephant rested upon a tortoise; and when they said, 'How about the tortoise?' the Indian said, 'Suppose we change the subject.'

Notable modern allusions or variations

References to "turtles all the way down" have been made in a variety of modern contexts. For example, "Turtles All the Way Down" is the name of a song by country artist Sturgill Simpson that appears on his 2014 album Metamodern Sounds in Country Music.^[13] Turtles All The Way Down is also the title of a 2017 novel by John Green about a teenage girl with obsessive compulsive disorder.^[14]

Stephen Hawking incorporates the saying into the beginning of his 1988 book A Brief History of Time:^[15]

A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: "What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise." The scientist gave a superior smile before replying, "What is the tortoise standing on?" "You're very clever, young man, very clever," said the old lady. "But it's turtles all the way down!"

Justice Antonin Scalia of the U.S. Supreme Court discussed his "favored version" of the saying in a footnote to his plurality opinion in Rapanos v. United States:^[16]

In our favored version, an Eastern guru affirms that the earth is supported on the back of a tiger. When asked what supports the tiger, he says it stands upon an elephant; and when asked what supports the elephant he says it is a giant turtle. When asked, finally, what supports the giant turtle, he is briefly taken aback, but quickly replies "Ah, after that it is turtles all the way down."

Solipsism

From Wikipedia, the free encyclopedia

Solipsism (/ˈsɒlɪpsɪzəm/ ( listen); from Latin solus, meaning 'alone', and ipse, meaning 'self') is the philosophical idea that only one's own mind is sure to exist. As an epistemological position, solipsism holds that knowledge of anything outside one's own mind is unsure; the external world and other minds cannot be known and might not exist outside the mind. As a metaphysical position, solipsism goes further to the conclusion that the world and other minds do not exist.

Varieties

There are varying degrees of solipsism that parallel the varying degrees of skepticism:

Metaphysical solipsism

Metaphysical solipsism is a variety of solipsism. Based on a philosophy of subjective idealism, metaphysical solipsists maintain that the self is the only existing reality and that all other realities, including the external world and other persons, are representations of that self, and have no independent existence.^{[citation needed]} There are several versions of metaphysical solipsism, such as Caspar Hare's egocentric presentism (or perspectival realism), in which other people are conscious, but their experiences are simply not present.^{[citation needed]}

Epistemological solipsism

Epistemological solipsism is the variety of idealism according to which only the directly accessible mental contents of the solipsistic philosopher can be known. The existence of an external world is regarded as an unresolvable question rather than actually false.^[2] Further, one cannot also be certain as to what extent the external world exists independently of one's mind. For instance, it may be that a God-like being controls the sensations received by one's brain, making it appear as if there is an external world when most of it (excluding the God-like being and oneself) is false. However, the point remains that epistemological solipsists consider this an "unresolvable" question.^[2]

Methodological solipsism

Methodological solipsism is an agnostic variant of solipsism.^{[citation needed]} It exists in opposition to the strict epistemological requirements for "knowledge" (e.g. the requirement that knowledge must be certain). It still entertains the points that any induction is fallible. Methodological solipsism sometimes goes even further to say that even what we perceive as the brain is actually part of the external world, for it is only through our senses that we can see or feel the mind. Only the existence of thoughts is known for certain.
Importantly, methodological solipsists do not intend to conclude that the stronger forms of solipsism are actually true. They simply emphasize that justifications of an external world must be founded on indisputable facts about their own consciousness. The methodological solipsist believes that subjective impressions (empiricism) or innate knowledge (rationalism) are the sole possible or proper starting point for philosophical construction.^[3] Often methodological solipsism is not held as a belief system, but rather used as a thought experiment to assist skepticism (e.g. Descartes' cartesian skepticism).^{[citation needed]}

Main points

Denial of material existence, in itself, does not constitute solipsism.

A feature of the metaphysical solipsistic worldview is the denial of the existence of other minds. Since personal experiences are private and ineffable, another being's experience can be known only by analogy.

Philosophers try to build knowledge on more than an inference or analogy. The failure of Descartes' epistemological enterprise brought to popularity the idea that all certain knowledge may go no further than "I think; therefore I exist"^[4] without providing any real details about the nature of the "I" that has been proven to exist.^{[citation needed]}

The theory of solipsism also merits close examination because it relates to three widely held philosophical presuppositions, each itself fundamental and wide-ranging in importance:^[4]

1. My most certain knowledge is the content of my own mind—my thoughts, experiences, affects, etc.
2. There is no conceptual or logically necessary link between mental and physical—between, say, the occurrence of certain conscious experience or mental states and the 'possession' and behavioral dispositions of a 'body' of a particular kind (see the brain in a vat).

To expand on this a little further, the conceptual problem here is that the previous assumes mind or consciousness (which are attributes) can exist independent of some entity having this capability, i.e., that an attribute of an existant can exist apart from the existant itself. If one admits to the existence of an independent entity (e.g., your brain) having that attribute, the door is open.

3. The experience of a given person is necessarily private to that person.

Some people hold that, while it cannot be proven that anything independent of one's mind exists, the point that solipsism makes is irrelevant. This is because, whether the world as we perceive it exists independently or not, we cannot escape this perception (except via death), hence it is best to act assuming that the world is independent of our minds.^[5] For example, if one committed a crime, one is likely to be punished, causing potential distress to oneself even if the world was not independent of one's mind; therefore, it is in one's best interests and is most convenient to assume the world exists independently of one's mind.

There is also the issue of plausibility to consider. If one is the only mind in existence, then one is maintaining that one's mind alone created all of which one is apparently aware. This includes the symphonies of Beethoven, the works of Shakespeare, all of mathematics and science (which one can access via one's phantom libraries), etc. Critics of solipsism find this somewhat implausible. However, since as an example, people are able to construct entire worlds inside their minds while having dreams when asleep, and people have had dreams which included things such as music of Beethoven or the works of Shakespeare or maths or science in them, solipsists do have counter-arguments to justify their views being plausible.

History

Gorgias

Solipsism was first recorded by the Greek presocratic sophist, Gorgias (c. 483–375 BC) who is quoted by the Roman skeptic Sextus Empiricus as having stated:^[6]

1. Nothing exists.
2. Even if something exists, nothing can be known about it.
3. Even if something could be known about it, knowledge about it can't be communicated to others.

Much of the point of the Sophists was to show that "objective" knowledge was a literal impossibility.

Descartes

The foundations of solipsism are in turn the foundations of the view that the individual's understanding of any and all psychological concepts (thinking, willing, perceiving, etc.) is accomplished by making an analogy with his or her own mental states; i.e., by abstraction from inner experience. And this view, or some variant of it, has been influential in philosophy since Descartes elevated the search for incontrovertible certainty to the status of the primary goal of epistemology, whilst also elevating epistemology to "first philosophy".^{[citation needed]}

Berkeley

Portrait of George Berkeley by John Smybert, 1727

George Berkeley's arguments against materialism in favour of idealism provide the solipsist with a number of arguments not found in Descartes. While Descartes defends ontological dualism, thus accepting the existence of a material world (res extensa) as well as immaterial minds (res cogitans) and God, Berkeley denies the existence of matter but not minds, of which God is one.^[7]

Relation to other ideas

Idealism and materialism

One of the most fundamental debates in philosophy concerns the "true" nature of the world—whether it is some ethereal plane of ideas or a reality of atomic particles and energy. Materialism^[8] posits a real 'world out there,' as well as in and through us, that can be sensed—seen, heard, tasted, touched and felt, sometimes with prosthetic technologies corresponding to human sensing organs. (Materialists do not claim that human senses or even their prosthetics can, even when collected, sense the totality of the 'universe'; simply that what they collectively cannot sense cannot in any way be known to us.)

Materialists do not find this a useful way of thinking about the ontology and ontogeny of ideas, but we might say that from a materialist perspective pushed to a logical extreme communicable to an idealist (an "Away Team" perspective), ideas are ultimately reducible to a physically communicated, organically, socially and environmentally embedded 'brain state'. While reflexive existence is not considered by materialists to be experienced on the atomic level, the individual's physical and mental experiences are ultimately reducible to the unique tripartite combination of environmentally determined, genetically determined, and randomly determined interactions of firing neurons and atomic collisions.

As a correlative, the only thing that dreams and hallucinations prove are that some neurons can reorganize and 'clean house' 'on break' (often reforming according to emergent, prominent, or uncanny cultural themes), misfire, and malfunction. But for materialists, ideas have no primary reality as essences separate from our physical existence. From a materialist "Home Team" perspective, ideas are also social (rather than purely biological), and formed and transmitted and modified through the interactions between social organisms and their social and physical environments. This materialist perspective informs scientific methodology, insofar as that methodology assumes that humans have no access to omniscience and that therefore human knowledge is an ongoing, collective enterprise that is best produced via scientific and logical conventions adjusted specifically for material human capacities and limitations.^{[citation needed]}

Modern Idealists, on the other hand, believe that the mind and its thoughts are the only true things that exist. This is the reverse of what is sometimes called classical idealism or, somewhat confusingly, Platonic idealism due to the influence of Plato's Theory of Forms (εἶδος eidos or ἰδέα idea) which were not products of our thinking.^[9] The material world is ephemeral, but a perfect triangle or "beauty" is eternal. Religious thinking tends to be some form of idealism, as God usually becomes the highest ideal (such as Neoplatonism).^[8][10][11] On this scale, solipsism can be classed as idealism. Thoughts and concepts are all that exist, and furthermore, only the solipsist's own thoughts and consciousness exist. The so-called "reality" is nothing more than an idea that the solipsist has (perhaps unconsciously) created.

Cartesian dualism

There is another option: the belief that both ideals and "reality" exist. Dualists commonly argue that the distinction between the mind (or 'ideas') and matter can be proven by employing Leibniz' principle of the identity of indiscernibles which states that if two things share exactly the same qualities, then they must be identical, as in indistinguishable from each other and therefore one and the same thing. Dualists then attempt to identify attributes of mind that are lacked by matter (such as privacy or intentionality) or vice versa (such as having a certain temperature or electrical charge).^[12][13] One notable application of the identity of indiscernibles was by René Descartes in his Meditations on First Philosophy. Descartes concluded that he could not doubt the existence of himself (the famous cogito ergo sum argument), but that he could doubt the (separate) existence of his body. From this, he inferred that the person Descartes must not be identical to the Descartes body since one possessed a characteristic that the other did not: namely, it could be known to exist. Solipsism agrees with Descartes in this aspect, and goes further: only things that can be known to exist for sure should be considered to exist. The Descartes body could only exist as an idea in the mind of the person Descartes.^[14][15] Descartes and dualism aim to prove the actual existence of reality as opposed to a phantom existence (as well as the existence of God in Descartes' case), using the realm of ideas merely as a starting point, but solipsism usually finds those further arguments unconvincing. The solipsist instead proposes that his/her own unconscious is the author of all seemingly "external" events from "reality".

Philosophy of Schopenhauer

The World as Will and Representation is the central work of Arthur Schopenhauer. Schopenhauer saw the human will as our one window to the world behind the representation, the Kantian thing-in-itself. He believed, therefore, that we could gain knowledge about the thing-in-itself, something Kant said was impossible, since the rest of the relationship between representation and thing-in-itself could be understood by analogy as the relationship between human will and human body.

Idealism

The idealist philosopher George Berkeley argued that physical objects do not exist independently of the mind that perceives them. An item truly exists only as long as it is observed; otherwise, it is not only meaningless but simply nonexistent. The observer and the observed are one. Berkeley does attempt to show things can and do exist apart from the human mind and our perception, but only because there is an all-encompassing Mind in which all "ideas" are perceived – in other words, God, who observes all. Solipsism agrees that nothing exists outside of perception, but would argue that Berkeley falls prey to the egocentric predicament – he can only make his own observations, and thus cannot be truly sure that this God or other people exist to observe "reality". The solipsist would say it is better to disregard the unreliable observations of alleged other people and rely upon the immediate certainty of one's own perceptions.^[16]

Rationalism

Rationalism is the philosophical position that truth is best discovered by the use of reasoning and logic rather than by the use of the senses (see Plato's theory of Forms). Solipsism is also skeptical of sense-data.

Philosophical zombie

The theory of solipsism crosses over with the theory of the philosophical zombie in that all other seemingly conscious beings actually lack true consciousness, instead they only display traits of consciousness to the observer, who is the only conscious being there is.

Falsifiability and testability

Solipsism is not a falsifiable hypothesis as described by Karl Popper or Imre Lakatos: there does not seem to be an imaginable disproof.^[17]

One critical test is nevertheless to consider the induction from experience that the externally observable world does not seem, at first approach, to be directly manipulable purely by mental energies alone. One can indirectly manipulate the world through the medium of the physical body, but it seems impossible to do so through pure thought (e.g. via psychokinesis). It might be argued that if the external world were merely a construct of a single consciousness, i.e. the self, it could then follow that the external world should be somehow directly manipulable by that consciousness, and if it is not, then solipsism is false. An argument against this states the notion that such manipulation may be possible but barred from the conscious self via the subconscious self, a 'locked' portion of the mind that is still nevertheless the same mind. Lucid dreaming might be considered an example of when these locked portions of the subconscious become accessible. An argument against this might be brought up in asking why the subconscious mind would be locked. Also, the access to the autonomous ('locked') portions of the mind during the lucid dreaming is obviously much different (for instance: is relatively more transient) than the access to autonomous regions of the perceived nature.

The method of the typical scientist is materialist: they first assume that the external world exists and can be known. But the scientific method, in the sense of a predict-observe-modify loop, does not require the assumption of an external world. A solipsist may perform a psychological test on themselves, to discern the nature of the reality in their mind - however David Deutsch uses this fact to counter-argue: "outer parts" of solipsist, behave independently so they are independent for "narrowly" defined (conscious) self.^[18] A solipsist's investigations may not be proper science, however, since it would not include the co-operative and communitarian aspects of scientific inquiry that normally serve to diminish bias.

Minimalism

Solipsism is a form of logical minimalism. Many people are intuitively unconvinced of the nonexistence of the external world from the basic arguments of solipsism, but a solid proof of its existence is not available at present. The central assertion of solipsism rests on the nonexistence of such a proof, and strong solipsism (as opposed to weak solipsism) asserts that no such proof can be made. In this sense, solipsism is logically related to agnosticism in religion: the distinction between believing you do not know, and believing you could not have known.

However, minimality (or parsimony) is not the only logical virtue. A common misapprehension of Occam's Razor has it that the simpler theory is always the best. In fact, the principle is that the simpler of two theories of equal explanatory power is to be preferred. In other words: additional "entities" can pay their way with enhanced explanatory power. So the realist can claim that, while his world view is more complex, it is more satisfying as an explanation.

Solipsism in infants

Some developmental psychologists believe that infants are solipsistic, and that eventually children infer that others have experiences much like theirs and reject solipsism.^[19]

Hinduism

The earliest reference to Solipsism in Hindu philosophy is found in the Brihadaranyaka Upanishad, dated to early 1st millennium BCE.^[20] The Upanishad holds the mind to be the only god and all actions in the universe are thought to be a result of the mind assuming infinite forms.^[21] After the development of distinct schools of Indian philosophy, Advaita Vedanta and Samkhya schools are thought to have originated concepts similar to solipsism.^{[citation needed]}

Advaita Vedanta

Advaita is one of the six most known Hindu philosophical systems and literally means "non-duality". Its first great consolidator was Adi Shankaracharya, who continued the work of some of the Upanishadic teachers, and that of his teacher's teacher Gaudapada. By using various arguments, such as the analysis of the three states of experience—wakefulness, dream, and deep sleep, he established the singular reality of Brahman, in which Brahman, the universe and the Atman or the Self, were one and the same.

One who sees everything as nothing but the Self, and the Self in everything one sees, such a seer withdraws from nothing. For the enlightened, all that exists is nothing but the Self, so how could any suffering or delusion continue for those who know this oneness?

— Ishopanishad: sloka 6, 7

The concept of the Self in the philosophy of Advaita could be interpreted as solipsism. However, the transhuman, theological implications of the Self in Advaita protect it from true solipsism as found in the west. Similarly, the Vedantic text Yogavasistha, escapes charge of solipsism because the real "I" is thought to be nothing but the absolute whole looked at through a particular unique point of interest.^[22]

Advaita is also thought to strongly diverge from solipsism in that, the former is a system of exploration of one's mind in order to finally understand the nature of the self and attain complete knowledge. The unity of existence is said to be directly experienced and understood at the end as a part of complete knowledge. On the other hand, solipsism posits the non-existence of the external void right at the beginning, and says that no further inquiry is possible.^{[citation needed]}

Samkhya and Yoga

Samkhya philosophy, which is sometimes seen as the basis of Yogic thought,^[23] adopts a view that matter exists independently of individual minds. Representation of an object in an individual mind is held to be a mental approximation of the object in the external world.^[24] Therefore, Samkhya chooses representational realism over epistemological solipsism. Having established this distinction between the external world and the mind, Samkhya posits the existence of two metaphysical realities Prakriti (matter) and Purusha (consciousness).

Buddhism

Some misinterpretations of Buddhism assert that external reality is an illusion, and sometimes this position is [mis]understood as metaphysical solipsism. Buddhist philosophy, though, generally holds that the mind and external phenomena are both equally transient, and that they arise from each other. The mind cannot exist without external phenomena, nor can external phenomena exist without the mind. This relation is known as "dependent arising" (pratityasamutpada).

The Buddha stated, "Within this fathom long body is the world, the origin of the world, the cessation of the world and the path leading to the cessation of the world".^[25] Whilst not rejecting the occurrence of external phenomena, the Buddha focused on the illusion created within the mind of the perceiver by the process of ascribing permanence to impermanent phenomena, satisfaction to unsatisfying experiences, and a sense of reality to things that were effectively insubstantial.

Mahayana Buddhism also challenges as illusion the idea that one can experience an 'objective' reality independent of individual perceiving minds.

From the standpoint of Prasangika (a branch of Madhyamaka thought), external objects do exist, but are devoid of any type of inherent identity: "Just as objects of mind do not exist [inherently], mind also does not exist [inherently]".^[26] In other words, even though a chair may physically exist, individuals can only experience it through the medium of their own mind, each with their own literal point of view. Therefore, an independent, purely 'objective' reality could never be experienced.

The Yogacara (sometimes translated as "Mind only") school of Buddhist philosophy contends that all human experience is constructed by mind. Some later representatives of one Yogacara subschool (Prajnakaragupta, Ratnakīrti) propounded a form of idealism that has been interpreted as solipsism. A view of this sort is contained in the 11th-century treatise of Ratnakirti, "Refutation of the existence of other minds" (Santanantara dusana), which provides a philosophical refutation of external mind-streams from the Buddhist standpoint of ultimate truth (as distinct from the perspective of everyday reality).^[27]

In addition to this, the Bardo Thodol, Tibet's famous book of the dead, repeatedly states that all of reality is a figment of one's perception, although this occurs within the "Bardo" realm (post-mortem). For instance, within the sixth part of section titled "The Root Verses of the Six Bardos", there appears the following line: "May I recognize whatever appeareth as being mine own thought-forms";^[28] there are many lines in similar ideal.

Philosophical zombie

From Wikipedia, the free encyclopedia

A philosophical zombie or p-zombie in the philosophy of mind and perception is a hypothetical being that from the outside is indistinguishable from a normal human being but lacks conscious experience, qualia, or sentience. For example, if a philosophical zombie was poked with a sharp object it would not feel any pain sensation, yet could behave exactly as if it does feel pain (it may say "ouch", recoil from the stimulus, and say that it is feeling pain).

The notion of a philosophical zombie is used mainly in thought experiments intended to support arguments (often called "zombie arguments") against forms of physicalism such as materialism, behaviorism and functionalism. Physicalism is the idea that all aspects of human nature can be explained by physical means: specifically, all aspects of human nature and perception can be explained from a neurobiological standpoint. Some philosophers, such as David Chalmers, argue that since a zombie is defined as physiologically indistinguishable from human beings, even its logical possibility would be a sound refutation of physicalism, as it would establish that the existence of conscious experience is a further fact.^[2] However, physicalists like Daniel Dennett counter that Chalmers's physiological zombies are logically incoherent and thus impossible.^[3][4]

Types of zombies

Though philosophical zombies are widely used in thought experiments, the detailed articulation of the concept is not always the same. P-zombies were introduced primarily to argue against specific types of physicalism such as behaviorism, according to which mental states exist solely as behavior: belief, desire, thought, consciousness, and so on, are simply certain kinds of behavior or tendencies towards behaviors. A p-zombie that is behaviorally indistinguishable from a normal human being but lacks conscious experiences is therefore not logically possible according to the behaviorist, so an appeal to the logical possibility of a p-zombie furnishes an argument that behaviorism is false. Proponents of zombie arguments generally accept that p-zombies are not physically possible, while opponents necessarily deny that they are metaphysically or even logically possible.

The unifying idea of the zombie is of a human that has no conscious experience, but one might distinguish various types of zombie used in different thought experiments as follows:

• A behavioral zombie that is behaviorally indistinguishable from a human.
• A neurological zombie that has a human brain and is generally physiologically indistinguishable from a human.^[5]
• A soulless zombie that lacks a soul.

Zombie arguments

Zombie arguments often support lines of reasoning that aim to show that zombies are metaphysically possible in order to support some form of dualism – in this case the view that the world includes two kinds of substance (or perhaps two kinds of property); the mental and the physical.^[6] According to physicalism, physical facts determine all other facts. Since any fact other than that of consciousness may be held to be the same for a p-zombie and a normal conscious human, it follows that physicalism must hold that p-zombies are either not possible or are the same as normal humans.

The zombie argument is a version of general modal arguments against physicalism such as that of Saul Kripke^[7] and the kind of physicalism known as type-identity theory. Further such arguments were notably advanced in the 1970s by Thomas Nagel (1970; 1974) and Robert Kirk (1974) but the general argument was most famously developed in detail by David Chalmers in The Conscious Mind (1996). According to Chalmers one can coherently conceive of an entire zombie world, a world physically indistinguishable from this world but entirely lacking conscious experience. The counterpart of every conscious being in our world would be a p-zombie. Since such a world is conceivable, Chalmers claims, it is metaphysically possible, which is all the argument requires. Chalmers states: "Zombies are probably not naturally possible: they probably cannot exist in our world, with its laws of nature."^[8] The outline structure of Chalmers' version of the zombie argument is as follows;

1. According to physicalism, all that exists in our world (including consciousness) is physical.
2. Thus, if physicalism is true, a metaphysically possible world in which all physical facts are the same as those of the actual world must contain everything that exists in our actual world. In particular, conscious experience must exist in such a possible world.
3. In fact we can conceive of a world physically indistinguishable from our world but in which there is no consciousness (a zombie world). From this (so Chalmers argues) it follows that such a world is metaphysically possible.
4. Therefore, physicalism is false. (The conclusion follows from 2. and 3. by modus tollens.)

The above is a strong formulation of the zombie argument. There are other formulations of the zombies-type argument which follow the same general form. The premises of the general zombies argument are implied by the premises of all the specific zombie arguments. A general zombies argument is in part motivated by potential disagreements between various anti-physicalist views. For example, an anti-physicalist view can consistently assert that p-zombies are metaphysically impossible but that inverted qualia (such as inverted spectra) or absent qualia (partial zombiehood) are metaphysically possible. Premises regarding inverted qualia or partial zombiehood can substitute premises regarding p-zombies to produce variations of the zombie argument. The metaphysical possibility of a physically indistinguishable world with either inverted qualia or partial zombiehood would imply that physical truths don't metaphysically necessitate phenomenal truths. To formulate the general form of the zombies argument, take the sentence 'P' to be true if and only if the conjunct of all microphysical truths of our world obtain, take the sentence 'Q' to be true if some phenomenal truth, that obtains in the actual world, obtains. The general argument goes as follows.

1. It is conceivable that P is true and Q is not true.
2. If it is conceivable that P is true and Q is not true then it is metaphysically possible that P is true and Q not true.
3. If it is metaphysically possible that P is true and Q is not true then physicalism is false.
4. Therefore, physicalism is false.^[9]

Q can be false in a possible world if any of the following obtains: (1) there exists at least one invert relative to the actual world (2) there is at least one absent quale relative to the actual world (3) all actually conscious beings are p-zombies (all actual qualia are absent qualia).

Responses

Chalmers' argument is logically valid: if its premises are true then the conclusion must be true. However, other philosophers dispute that its premises are true. For example, is such a world really possible? Chalmers states that "it certainly seems that a coherent situation is described; I can discern no contradiction in the description."^[10] This leads to the questions of the relevant notion of "possibility": is the scenario described in premise 3 possible in the sense that is suggested in premise 2? Most physicalist responses deny that the premise of a zombie scenario is possible.

Many physicalist philosophers argued that this scenario eliminates itself by its description; the basis of physicalist argument is that the world is defined entirely by physicality, thus a world that was physically identical would necessarily contain consciousness, as consciousness would necessarily be generated from any set of physical circumstances identical to our own.

One can hold that zombies are a logical possibility but not a metaphysical possibility. If logical possibility does not entail metaphysical possibility across the domain of relevant truths, then the mere logical possibility of zombies is not sufficient to establish their metaphysical possibility. The zombie argument claims that one can tell by the power of reason that such a "zombie scenario" is metaphysically possible. Chalmers states; "From the conceivability of zombies, proponents of the argument infer their metaphysical possibility"^[8] and argues that this inference, while not generally legitimate, is legitimate for phenomenal concepts such as consciousness since we must adhere to "Kripke's insight that for phenomenal concepts, there is no gap between reference-fixers and reference (or between primary and secondary intentions)." That is, for phenomenal concepts, conceivability implies possibility. According to Chalmers, whatever is logically possible is also, in the sense relevant here, metaphysically possible.^[11]

Another response is denial of the idea that qualia and related phenomenal notions of the mind are in the first place coherent concepts. Daniel Dennett and others argue that while consciousness and subjective experience exist in some sense, they are not as the zombie argument proponent claims. The experience of pain, for example, is not something that can be stripped off a person's mental life without bringing about any behavioral or physiological differences. Dennett believes that consciousness is a complex series of functions and ideas. If we all can have these experiences the idea of the p-zombie is meaningless.

Dennett argues that "when philosophers claim that zombies are conceivable, they invariably underestimate the task of conception (or imagination), and end up imagining something that violates their own definition".^[3][4] He coined the term "zimboes" – p-zombies that have second-order beliefs – to argue that the idea of a p-zombie is incoherent;^[12] "Zimboes think^Z they are conscious, think^Z they have qualia, think^Z they suffer pains – they are just 'wrong' (according to this lamentable tradition), in ways that neither they nor we could ever discover!".^[4] Under (reductive) physicalism, one is inclined to believe either that anyone including oneself might be a zombie, or that no one can be a zombie – following from the assertion that one's own conviction about being, or not being a zombie is (just) a product of the physical world and is therefore no different from anyone else's. P-zombies in an observed world would be indistinguishable from the observer, even hypothetically (when the observer makes no assumptions regarding the validity of their convictions). Furthermore, when concept of self is deemed to correspond to physical reality alone (reductive physicalism), philosophical zombies are denied by definition. When a distinction is made in one's mind between a hypothetical zombie and oneself (assumed not to be a zombie), the hypothetical zombie, being a subset of the concept of oneself, must entail a deficit in observables (cognitive systems), a "seductive error"^[4] contradicting the original definition of a zombie.

Verificationism^[1] states that, for words to have meaning, their use must be open to public verification. Since it is assumed that we can talk about our qualia, the existence of zombies is impossible. A related argument is that of "zombie-utterance". If someone were to say they love the smell of some food, a zombie producing the same reaction would be perceived as a person having complex thoughts and ideas in their head indicated by the ability to vocalize it. If zombies were without awareness of their perceptions the idea of uttering words could not occur to them. Therefore, if a zombie has the ability to speak, it is not a zombie.

Artificial intelligence researcher Marvin Minsky saw the argument as circular. The proposition of the possibility of something physically identical to a human but without subjective experience assumes that the physical characteristics of humans are not what produces those experiences, which is exactly what the argument was claiming to prove.^[13] Richard Brown agrees that the zombie argument is circular. To show this, he proposes "zoombies", which are creatures nonphysically identical to people in every way and lack phenomenal consciousness. If zoombies existed, they would refute dualism because they would show that consciousness is not nonphysical, i.e., is physical. Paralleling the argument from Chalmers: It's conceivable that zoombies exist, so it's possible they exist, so dualism is false. Given the symmetry between the zombie and zoombie arguments, we can't arbitrate the physicalism/dualism question a priori.^[14]

Stephen Yablo's (1998) response is to provide an error theory to account for the intuition that zombies are possible. Notions of what counts as physical and as physically possible change over time so conceptual analysis is not reliable here. Yablo says he is "braced for the information that is going to make zombies inconceivable, even though I have no real idea what form the information is going to take."^[15]

The zombie argument is difficult to assess because it brings to light fundamental disagreements about the method and scope of philosophy itself and the nature and abilities of conceptual analysis. Proponents of the zombie argument may think that conceptual analysis is a central part of (if not the only part of) philosophy and that it certainly can do a great deal of philosophical work. However others, such as Dennett, Paul Churchland and W.V.O. Quine, have fundamentally different views. For this reason, discussion of the zombie argument remains vigorous in philosophy.

Some accept modal reasoning in general but deny it in the zombie case. Christopher S. Hill and Brian P. Mclaughlin suggest that the zombie thought experiment combines imagination of a "sympathetic" nature (putting oneself in a phenomenal state) and a "perceptual" nature (imagining becoming aware of something in the outside world). Each type of imagination may work on its own, but they're not guaranteed to work when both used at the same time. Hence Chalmers's argument needn't go through.^[16]:448 Moreover, while Chalmers defuses criticisms of the view that conceivability can tell us about possibility, he provides no positive defense of the principle. As an analogy, the generalized continuum hypothesis has no known counterexamples, but this doesn't mean we must accept it. And indeed, the fact that Chalmers concludes we have epiphenomenal mental states that don't cause our physical behavior seems one reason to reject his principle.^{[16]:449–51}

Another way to construe the zombie hypothesis is epistemically – as a problem of causal explanation, rather than as a problem of logical or metaphysical possibility. The "explanatory gap" – also called the "hard problem of consciousness" – is the claim that (to date) no one has provided a convincing causal explanation of how and why we are conscious. It is a manifestation of the very same gap that (to date) no one has provided a convincing causal explanation of how and why we are not zombies.^[17]

Related thought-experiments

Frank Jackson's Mary's room argument is based around a hypothetical scientist, Mary, who is forced to view the world through a black-and-white television screen in a black and white room. Mary is a brilliant scientist who knows everything about the neurobiology of vision. Even though Mary knows everything about color and its perception (e.g. what combination of wavelengths makes the sky seem blue), she has never seen color. If Mary were released from this room and were to experience color for the first time, would she learn anything new? Jackson initially believed this supported epiphenomenalism (mental phenomena are the effects, but not the causes, of physical phenomena) but later changed his views to physicalism, suggesting that Mary is simply discovering a new way for her brain to represent qualities that exist in the world.

Swampman is an imaginary character introduced by Donald Davidson. If Davidson goes hiking in a swamp and is struck and killed by a lightning bolt while nearby another lightning bolt spontaneously rearranges a bunch of molecules so that, entirely by coincidence, they take on exactly the same form that Davidson's body had at the moment of his untimely death then this being, 'Swampman', has a brain structurally identical to that which Davidson had and will thus presumably behave exactly like Davidson. He will return to Davidson's office and write the same essays he would have written, recognize all of his friends and family and so forth.

John Searle's Chinese room argument deals with the nature of artificial intelligence: it imagines a room in which a conversation is held by means of written Chinese characters that the subject cannot actually read, but is able to manipulate meaningfully using a set of algorithms. Searle holds that a program cannot give a computer a "mind" or "understanding", regardless of how intelligently it may make it behave. Stevan Harnad argues that Searle's critique is really meant to target functionalism and computationalism, and to establish neuroscience as the only correct way to understand the mind.

3Q: Richard Milner on a new U.S. particle accelerator

Proposal for powerful particle collider gets National Academies’ go-ahead.

Jennifer Chu | MIT News Office
July 24, 2018
Original link:  http://news.mit.edu/2018/3q-richard-milner-new-us-particle-accelerator-0724?utm_source=&utm_medium=&utm_campaign= 

Comment

The case for an ambitious new particle accelerator to be built in the United States has just gotten a major boost.

Today, the National Academies of Sciences, Engineering, and Medicine have endorsed the development of the Electron Ion Collider, or EIC. The proposed facility, consisting of two intersecting accelerators, would smash together beams of protons and electrons traveling at nearly the speed of light. In the aftermath of each collision, scientists should see “snapshots” of the particles’ inner structures, much like a CT scan for atoms. From these images, scientists hope to piece together a multidimensional picture, with unprecedented depth and clarity, of the quarks and gluons that bind together protons and all the visible matter in the universe.

The EIC, if built, would significantly advance the field of quantum chromodynamics, which seeks to answer fundamental questions in physics, such as how quarks and gluons produce the strong force — the “glue” that holds all matter together. If constructed, the EIC would be the largest accelerator facility in the U.S. and, worldwide, second only to the Large Hadron Collider at CERN. MIT physicists, including Richard Milner, professor of physics at MIT, have been involved from the beginning in making the case for the EIC.

MIT News checked in with Milner, a member of the Laboratory for Nuclear Science, about the need for a new particle collider and its prospects going forward.   

Q: Tell us a bit about the history of this design. What has it taken to make the case for this new particle accelerator?

A: The development of both the scientific and technical case for the EIC has been in progress for about two decades. With the development of quantum chromodynamics (QCD) in the 1970s by MIT physics Professor Frank Wilczek and others, nuclear physicists have long sought to bridge the gap between QCD and the successful theory of nuclei based on experimentally observable particles, where the fundamental constituents are the undetectable quarks and gluons. 

A high-energy collider with the ability to collide electrons with the full range of nuclei at high rates and to have the electrons and nucleons polarized was identified as the essential tool to construct this bridge. High-energy electron scattering from the proton was how quarks were experimentally discovered at SLAC in the late 1960s (by MIT physics faculty Henry Kendall and Jerome Friedman and colleagues), and it is the accepted technique to directly probe the fundamental quark and gluon structure of matter.

Significant initial impetus for the EIC came from nuclear physicists at the university user-facilities at the University of Indiana and MIT as well as from physicists seeking to understand the origin of the proton’s spin, at laboratories and universities in the U.S. and Europe. Over the last three long-range planning exercises by U.S. nuclear physicists in 2002, 2007, and 2015, the case for the EIC has matured and strengthened. After the 2007 exercise, the two U.S. flagship nuclear facilities, namely the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Continuous Electron Beam Accelerator Facility at Jefferson Laboratory, took a leadership role in coordinating EIC activities across the broad U.S. QCD community. This led to the production in 2012 of a succinct summary of the science case, “Electron-Ion Collider: The Next QCD Frontier (Understanding the glue that binds us all).”

The 2015 planning exercise established the EIC as the highest priority for new facility construction in U.S. nuclear physics after present commitments are fulfilled.    This led to the formation of a committee by the U.S. National Academy of Sciences (NAS) to assess the EIC science case. The NAS committee deliberated for about a year and the report has been publicly released this month.

Q: Give us an idea of how powerful this new collider will be and what kind of new interactions it will produce. What kinds of phenomena will it help to explain?

A: The EIC will be a powerful and unique new accelerator that will offer an unprecedented window into the fundamental structure of matter. The electron-ion collision rate at the EIC will be high, more than two orders of magnitude greater than was possible at the only previous electron-proton collider, namely HERA, which operated at the DESY laboratory in Hamburg, Germany, from 1992 to 2007.  With the EIC, physicists will be able to image the virtual quarks and gluons that make up protons, neutrons, and nuclei, with unprecedented spatial resolution and shutter speed. A goal is to provide images of the fundamental structure of the microcosm that can be appreciated broadly by humanity: to answer questions such as, what does a proton look like? And what does a nucleus look like?

There are three central scientific issues that can be addressed by an electron-ion collider. The first goal is to understand in detail the mechanisms within QCD by which the mass of protons and neutrons, and thus the mass of all the visible matter in the universe, is generated. The problem is that while gluons have no mass, and quarks are nearly massless, the protons and neutrons that contain them are heavy, making up most of the visible mass of the universe. The total mass of a nucleon is some 100 times greater than the mass of the various quarks it contains.

The second issue is to understand the origin of the intrinsic angular momentum, or spin, of nucleons, a fundamental property that underlies many practical applications, including magnetic resonance imaging (MRI). How the angular momentum, both intrinsic as well as orbital, of the internal quarks and gluons gives rise to the known nucleon spin is not understood. And thirdly, the nature of gluons in matter — that is, their arrangements or states — and the details of how they hold matter together, is not well-known. Gluons in matter are a little like dark matter in the universe: unseen but playing a crucial role. An electron-ion collider would potentially reveal new states resulting from the close packing of many gluons within nucleons and nuclei. These issues are fundamental to our understanding of the matter in the universe.

Q: What role will MIT have in this project going forward?

A: At present, more than a dozen MIT physics department faculty lead research groups in the Laboratory for Nuclear Science that work directly on understanding the fundamental structure of matter as described by QCD. It is the largest university-based group in the U.S. working on QCD. Theoretical research is focused at the Center for Theoretical Physics, and experimentalists rely heavily on the Bates Research and Engineering Center for technical support.

MIT theorists are carrying out important calculations using the world’s most powerful computers to understand fundamental aspects of QCD. MIT experimental physicists are conducting experiments at existing facilities, such as BNL, CERN, and Jefferson Laboratory, to reach new insight and to develop new techniques that will be used at the EIC. Further, R&D into new polarized sources, detectors, and innovative data-acquisition schemes by MIT scientists and engineers is in progress. It is anticipated that these efforts will ramp up as the realization of the EIC approaches.

It is anticipated that the U.S. Department of Energy Office of Science will initiate in the near future the official process for EIC by which the U.S. government approves, funds, and constructs new, large scientific facilities. Critical issues are the selection of the site for EIC and the participation of international users. An EIC user group has formed with the participation of more than 700 PhD scientists from over 160 laboratories and universities around the world. If the realization of EIC follows a schedule comparable to that of past large facilities, it should be doing science by about 2030. MIT has a long history of providing leadership in U.S. nuclear physics and will continue to play a significant role as we proceed along the path to EIC.