Solipsism 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. This extreme position is claimed to be
irrefutable, as the solipsist believes themself to be the only true
authority, all others being creations of their own mind.
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. 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.
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.
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.
Methodological solipsism
Methodological solipsism is an agnostic variant of solipsism. 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. 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).
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" without providing any real details about the nature of the "I" that has been proven to exist.
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:
- My most certain knowledge is the content of my own mind—my thoughts, experiences, affects, etc.
- 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.
- The experience of a given person is necessarily private to that person.
To expand on point 2 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 existent can exist apart from
the existent itself. If one admits to the existence of an independent
entity (e.g., your brain) having that attribute, the door is open.
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.
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, for 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 math 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 sceptic Sextus Empiricus as having stated:
- Nothing exists.
- Even if something exists, nothing can be known about it.
- 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. (See also comments credited to Protagoras of Abdera).
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".
Berkeley
George Berkeley's arguments against materialism in favor 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.
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
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.
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. 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). 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). 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.
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.
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. 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.
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.
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.
Hinduism
The earliest reference to Solipsism in Hindu philosophy is found in the Brihadaranyaka Upanishad, dated to early 1st millennium BCE. 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. After the development of distinct schools of Indian philosophy, Advaita Vedanta and Samkhya schools are thought to have originated concepts similar to solipsism.
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.
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 world right at
the beginning, and says that no further inquiry is possible.
Samkhya and Yoga
Samkhya philosophy, which is sometimes seen as the basis of Yogic thought,
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. 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".
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 the illusion of 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]".
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).
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 the
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"; there are many lines in similar ideal.