Solipsism ( ; ) is the
philosophical
Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...
idea that only one's
mind
The mind is that which thinks, feels, perceives, imagines, remembers, and wills. It covers the totality of mental phenomena, including both conscious processes, through which an individual is aware of external and internal circumstances ...
is sure to exist. As an
epistemological
Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called "the theory of knowledge", it explores different types of knowledge, such as propositional knowledge about facts, practical knowled ...
position, solipsism holds that
knowledge
Knowledge is an Declarative knowledge, awareness of facts, a Knowledge by acquaintance, familiarity with individuals and situations, or a Procedural knowledge, practical skill. Knowledge of facts, also called propositional knowledge, is oft ...
of anything outside one's own mind is unsure; the
external world
Reality is the sum or aggregate of everything in existence; everything that is not imaginary. Different cultures and academic disciplines conceptualize it in various ways.
Philosophical questions about the nature of reality, existence, or b ...
and
other minds cannot be known and might not exist outside the mind.
Varieties
There are varying degrees of solipsism that parallel the varying degrees of
skepticism
Skepticism ( US) or scepticism ( UK) is a questioning attitude or doubt toward knowledge claims that are seen as mere belief or dogma. For example, if a person is skeptical about claims made by their government about an ongoing war then the p ...
:
Metaphysical
Metaphysical
Metaphysics is the branch of philosophy that examines the basic structure of reality. It is traditionally seen as the study of mind-independent features of the world, but some theorists view it as an inquiry into the conceptual framework of h ...
solipsism is a variety of solipsism based on a philosophy of
subjective idealism
Subjective idealism, or empirical idealism or immaterialism, is a form of philosophical monism that holds that only minds and mental contents exist. It entails and is generally identified or associated with immaterialism, the doctrine that m ...
. Metaphysical solipsists maintain that the
self
In philosophy, the self is an individual's own being, knowledge, and values, and the relationship between these attributes.
The first-person perspective distinguishes selfhood from personal identity. Whereas "identity" is (literally) same ...
is the only existing reality and that all other realities, including the external world and other persons, are representations of that self, having no independent existence. There are several versions of metaphysical solipsism, such as Caspar Hare's
egocentric presentism
Egocentric presentism is a form of solipsism introduced by Caspar Hare in which other persons can be conscious, but their experiences are simply not .
Similarly, in related work, Hare argues for a theory of perspectival realism in which other pe ...
(or
perspectival realism
In Caspar Hare's theory of perspectival realism, there is a defining ''intrinsic'' property that the things that are in perceptual awareness have. Consider seeing object A but not object B. Of course, we can say that the visual experience of A i ...
), in which other people are conscious, but their experiences are simply not ''present''.
Epistemological
Epistemological solipsism is the variety of
idealism
Idealism in philosophy, also known as philosophical realism or metaphysical idealism, is the set of metaphysics, metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, Spirit (vital essence), spirit, or ...
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 the mind, 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
Methodological solipsism is an
agnostic
Agnosticism is the view or belief that the existence of God, the divine, or the supernatural is either unknowable in principle or unknown in fact. (page 56 in 1967 edition) It can also mean an apathy towards such religious belief and refer to ...
variant of solipsism. It exists in opposition to the strict
epistemological
Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called "the theory of knowledge", it explores different types of knowledge, such as propositional knowledge about facts, practical knowled ...
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.
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
In philosophy, empiricism is an epistemological view which holds that true knowledge or justification comes only or primarily from sensory experience and empirical evidence. It is one of several competing views within epistemology, along ...
) or innate knowledge (
rationalism
In philosophy, rationalism is the Epistemology, epistemological view that "regards reason as the chief source and test of knowledge" or "the position that reason has precedence over other ways of acquiring knowledge", often in contrast to ot ...
) 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
A thought experiment is an imaginary scenario that is meant to elucidate or test an argument or theory. It is often an experiment that would be hard, impossible, or unethical to actually perform. It can also be an abstract hypothetical that is ...
to assist
skepticism
Skepticism ( US) or scepticism ( UK) is a questioning attitude or doubt toward knowledge claims that are seen as mere belief or dogma. For example, if a person is skeptical about claims made by their government about an ongoing war then the p ...
(''e.g.''
René Descartes
René Descartes ( , ; ; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and Modern science, science. Mathematics was paramou ...
'
Cartesian skepticism).
Main points
Mere denial of material existence, in itself, does not necessarily constitute solipsism.
Philosophers generally try to build knowledge on more than an inference or analogy. Well-known frameworks such as Descartes' epistemological enterprise brought to popularity the idea that all
certain knowledge may go no further than ''
"I think; therefore I exist."''
However, Descartes' view does not provide any 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:
* One's most certain knowledge is the content of one's own mind—''my''
thoughts
In their most common sense, the terms thought and thinking refer to cognitive processes that can happen independently of sensory stimulation. Their most paradigmatic forms are judging, reasoning, concept formation, problem solving, and delibe ...
, experiences, affects, etc.
* There is no conceptual or logically necessary link between mental and physical—between, for example, 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 the second point, the conceptual problem is that the previous point assumes
mind
The mind is that which thinks, feels, perceives, imagines, remembers, and wills. It covers the totality of mental phenomena, including both conscious processes, through which an individual is aware of external and internal circumstances ...
or
consciousness
Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, an ...
(which are attributes) can exist independent of some entity having this attribute (a capability in this case), 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., the brain) having that attribute, the door is open to an independent reality. (See
Brain in a vat
In philosophy, the brain in a vat (BIV) is a scenario used in a variety of thought experiments intended to draw out certain features of human conceptions of knowledge, reality, truth, mind, consciousness, and Meaning (philosophy of language), m ...
)
Some philosophers 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, hence it is best to act assuming that the world is independent of our minds.
History
Origins of solipsist thought are found in Greece and later Enlightenment thinkers such as
Thomas Hobbes
Thomas Hobbes ( ; 5 April 1588 – 4 December 1679) was an English philosopher, best known for his 1651 book ''Leviathan (Hobbes book), Leviathan'', in which he expounds an influential formulation of social contract theory. He is considered t ...
and Descartes.
Gorgias
Solipsism was first recorded by the Greek
presocratic sophist
A sophist () was a teacher in ancient Greece in the fifth and fourth centuries BCE. Sophists specialized in one or more subject areas, such as philosophy, rhetoric, music, athletics and mathematics. They taught ''arete'', "virtue" or "excellen ...
,
Gorgias
Gorgias ( ; ; – ) was an ancient Greek sophist, pre-Socratic philosopher, and rhetorician who was a native of Leontinoi in Sicily. Several doxographers report that he was a pupil of Empedocles, although he would only have been a few years ...
(–375 BC), who is quoted by the
Roman
Roman or Romans most often refers to:
*Rome, the capital city of Italy
*Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of Roman civilization
*Epistle to the Romans, shortened to Romans, a letter w ...
sceptic Sextus Empiricus
Sextus Empiricus (, ; ) was a Greek Pyrrhonist philosopher and Empiric school physician with Roman citizenship. His philosophical works are the most complete surviving account of ancient Greek and Roman Pyrrhonism, and because of the argument ...
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 cannot be communicated to others.
Much of the point of the sophists was to show that objective knowledge was a literal impossibility.
René 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
In their most common sense, the terms thought and thinking refer to cognitive processes that can happen independently of sensory stimulation. Their most paradigmatic forms are judging, reasoning, concept formation, problem solving, and delibe ...
,
willing,
perceiving, etc.) is accomplished by making an
analogy
Analogy is a comparison or correspondence between two things (or two groups of things) because of a third element that they are considered to share.
In logic, it is an inference or an argument from one particular to another particular, as oppose ...
with their own mental states; ''i.e.'', by
abstraction
Abstraction is a process where general rules and concepts are derived from the use and classifying of specific examples, literal (reality, real or Abstract and concrete, concrete) signifiers, first principles, or other methods.
"An abstraction" ...
from ''inner experience''. And this view, or some variant of it, has been influential in philosophy since René Descartes elevated the search for incontrovertible certainty to the status of the ''primary goal'' of
epistemology
Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called "the theory of knowledge", it explores different types of knowledge, such as propositional knowledge about facts, practical knowle ...
, whilst also elevating epistemology to "first philosophy".
Berkeley
George Berkeley
George Berkeley ( ; 12 March 168514 January 1753), known as Bishop Berkeley (Bishop of Cloyne of the Anglican Church of Ireland), was an Anglo-Irish philosopher, writer, and clergyman who is regarded as the founder of "immaterialism", a philos ...
's arguments against
materialism
Materialism is a form of monism, philosophical monism according to which matter is the fundamental Substance theory, substance in nature, and all things, including mind, mental states and consciousness, are results of material interactions. Acco ...
in favour of
idealism
Idealism in philosophy, also known as philosophical realism or metaphysical idealism, is the set of metaphysics, metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, Spirit (vital essence), spirit, or ...
provide the solipsist with a number of arguments not found in Descartes. While Descartes defends ontological
dualism
Dualism most commonly refers to:
* Mind–body dualism, a philosophical view which holds that mental phenomena are, at least in certain respects, not physical phenomena, or that the mind and the body are distinct and separable from one another
* P ...
, thus accepting the existence of a material world (''
res extensa
''Res extensa'' is one of the two substances described by René Descartes in his Cartesian ontology (often referred to as "radical dualism"), alongside '' res cogitans''. Translated from Latin, "''res extensa''" means "extended thing" while th ...
'') 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
Materialism is a form of monism, philosophical monism according to which matter is the fundamental Substance theory, substance in nature, and all things, including mind, mental states and consciousness, are results of material interactions. Acco ...
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 they collectively cannot sense what cannot in any way be known to us.) Materialists do not find this a useful way of thinking about the
ontology
Ontology is the philosophical study of existence, being. It is traditionally understood as the subdiscipline of metaphysics focused on the most general features of reality. As one of the most fundamental concepts, being encompasses all of realit ...
and
ontogeny
Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the ovum, egg to adult. The term can also be used to refer to t ...
of ideas, but we might say that from a materialist perspective pushed to a logical extreme communicable to an idealist, 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
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...
and atomic collisions.
For materialists, ideas have no primary reality as essences separate from our physical existence. From a materialist perspective, ideas are 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
In its most common sense, methodology is the study of research methods. However, the term can also refer to the methods themselves or to the philosophical discussion of associated background assumptions. A method is a structured procedure for bri ...
assumes that humans have no access to
omniscience
Omniscience is the property of possessing maximal knowledge. In Hinduism, Sikhism and the Abrahamic religions, it is often attributed to a divine being or an all-knowing spirit, entity or person. In Jainism, omniscience is an attribute that any ...
and that therefore human knowledge is an ongoing, collective enterprise that is best produced via
scientific
Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which stu ...
and
logical
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure of arg ...
conventions adjusted specifically for material human capacities and limitations.
Modern
idealists
Idealism in philosophy, also known as philosophical realism or metaphysical idealism, is the set of metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, spirit, or consciousness; that reality is enti ...
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
The Theory of Forms or Theory of Ideas, also known as Platonic idealism or Platonic realism, is a philosophical theory credited to the Classical Greek philosopher Plato.
A major concept in metaphysics, the theory suggests that the physical w ...
" due to the influence of Plato's
theory of forms
The Theory of Forms or Theory of Ideas, also known as Platonic idealism or Platonic realism, is a philosophical theory credited to the Classical Greek philosopher Plato.
A major concept in metaphysics, the theory suggests that the physical w ...
(εἶδος ''eidos'' or ἰδέα ''idea''), which were not products of our thinking. The material world is
ephemeral
Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...
, 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
Neoplatonism is a version of Platonic philosophy that emerged in the 3rd century AD against the background of Hellenistic philosophy and religion. The term does not encapsulate a set of ideas as much as a series of thinkers. Among the common id ...
).
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
The mind is that which thinks, feels, perceives, imagines, remembers, and wills. It covers the totality of mental phenomena, including both conscious processes, through which an individual is aware of external and internal circumstances ...
(or '
idea
In philosophy and in common usage, an idea (from the Greek word: ἰδέα (idea), meaning 'a form, or a pattern') is the results of thought. Also in philosophy, ideas can also be mental representational images of some object. Many philosophe ...
s') and matter can be proven by employing
Leibniz's principle of the ''
identity of indiscernibles
The identity of indiscernibles is an ontological principle that states that there cannot be separate objects or entities that have all their properties in common. That is, entities ''x'' and ''y'' are identical if every predicate possessed by ...
'', 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
The identity of indiscernibles is an ontological principle that states that there cannot be separate objects or entities that have all their properties in common. That is, entities ''x'' and ''y'' are identical if every predicate possessed by ...
was by René Descartes in his ''
Meditations on First Philosophy
''Meditations on First Philosophy, in which the existence of God and the immortality of the soul are demonstrated'' (), often called simply the ''Meditations'', is a philosophical treatise by René Descartes first published in Latin in 1641. T ...
''. Descartes concluded that he could not doubt the existence of ''himself'' (the famous ''
cogito ergo sum
The Latin , usually translated into English as "I think, therefore I am", is the "first principle" of René Descartes's philosophy. He originally published it in French language, French as , in his 1637 ''Discourse on the Method'', so as to re ...
'' 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 their own unconscious is the author of all seemingly "external" events from "reality".
Philosophy of Schopenhauer
''
The World as Will and Representation
''The World as Will and Representation'' (''WWR''; , ''WWV''), sometimes translated as ''The World as Will and Idea'', is the central work of the German philosopher Arthur Schopenhauer. The first edition was published in late 1818, with the date ...
'' is the central work of
Arthur Schopenhauer
Arthur Schopenhauer ( ; ; 22 February 1788 – 21 September 1860) was a German philosopher. He is known for his 1818 work ''The World as Will and Representation'' (expanded in 1844), which characterizes the Phenomenon, phenomenal world as ...
. Schopenhauer saw the human will as our one window to the world behind the representation, the Kantian
thing-in-itself
In Kantian philosophy, the thing-in-itself () is the status of objects as they are, independent of representation and observation. The concept of the thing-in-itself was introduced by the German philosopher Immanuel Kant, and over the following ...
. 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
Analogy is a comparison or correspondence between two things (or two groups of things) because of a third element that they are considered to share.
In logic, it is an inference or an argument from one particular to another particular, as oppose ...
as the relationship between human will and human body.
Idealism
The idealist philosopher
George Berkeley
George Berkeley ( ; 12 March 168514 January 1753), known as Bishop Berkeley (Bishop of Cloyne of the Anglican Church of Ireland), was an Anglo-Irish philosopher, writer, and clergyman who is regarded as the founder of "immaterialism", a philos ...
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. 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
In philosophy, rationalism is the Epistemology, epistemological view that "regards reason as the chief source and test of knowledge" or "the position that reason has precedence over other ways of acquiring knowledge", often in contrast to ot ...
is the philosophical position that
truth
Truth or verity is the Property (philosophy), property of being in accord with fact or reality.Merriam-Webster's Online Dictionarytruth, 2005 In everyday language, it is typically ascribed to things that aim to represent reality or otherwise cor ...
is best discovered by the use of reasoning and
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure o ...
rather than by the use of the senses (see Plato's
theory of forms
The Theory of Forms or Theory of Ideas, also known as Platonic idealism or Platonic realism, is a philosophical theory credited to the Classical Greek philosopher Plato.
A major concept in metaphysics, the theory suggests that the physical w ...
). Solipsism is also skeptical of
sense-data.
Philosophical zombie
The theory of solipsism crosses over with the theory of the
philosophical zombie
A philosophical zombie (or "p-zombie") is a being in a thought experiment in the philosophy of mind that is physically identical to a normal human being but does not have conscious experience.
For example, if a philosophical zombie were poked ...
in that other seemingly conscious beings may actually lack true
consciousness
Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, an ...
, instead they only display traits of consciousness to the observer, who may be the only conscious being there is.
Philosophy of identity
Some philosophers have connected solipsistic ideas with the philosophy of
personal identity
Personal identity is the unique numerical identity of a person over time. Discussions regarding personal identity typically aim to determine the necessary and sufficient conditions under which a person at one time and a person at another time ...
, as well as Hellie's
vertiginous question
Benj Hellie's vertiginous question asks why, of all the subjects of experience out there, ''this'' one—the one corresponding to the human being referred to as Benj Hellie—is the one whose experiences are ''lived''? (The reader is supposed to ...
.
Christian List
Christian List (born 1973) is a German philosopher and political scientist who serves as professor of philosophy and decision theory at the Ludwig Maximilian University of Munich and co-director of the Munich Center for Mathematical Philosop ...
argues that there exists a "quadrilemma" in metaphysics caused by the issues raised by the
problem of other minds
The problem of other minds is a Philosophy, philosophical problem traditionally stated as the following Epistemology, epistemological question: "Given that I can only observe the behavior of others, how can I know that others have minds?" The pr ...
and Hellie's
vertiginous question
Benj Hellie's vertiginous question asks why, of all the subjects of experience out there, ''this'' one—the one corresponding to the human being referred to as Benj Hellie—is the one whose experiences are ''lived''? (The reader is supposed to ...
. He argues that the four metaphysical claims of first-person realism, non-solipsism, non-fragmentation, and one-world cannot all be simultaneously true, and thus believing in both the existence of first-personal facts and a single, unified reality must imply that metaphysical solipsism is true. List has proposed a model he calls the "many-worlds theory of consciousness" as a possible alternative to solipsism.
Caspar Hare has argued for a weak form of solipsism with the concept of
egocentric presentism
Egocentric presentism is a form of solipsism introduced by Caspar Hare in which other persons can be conscious, but their experiences are simply not .
Similarly, in related work, Hare argues for a theory of perspectival realism in which other pe ...
, in which other persons can be conscious, but their experiences are simply not in the way one's own current experience is.
A related concept is
perspectival realism
In Caspar Hare's theory of perspectival realism, there is a defining ''intrinsic'' property that the things that are in perceptual awareness have. Consider seeing object A but not object B. Of course, we can say that the visual experience of A i ...
, in which things within perceptual awareness have a defining intrinsic property that exists absolutely and not relative to anything, of which several other philosophers have written reviews. Vincent Conitzer has argued for similar ideas on the basis of there being a connection between the
A-theory of time and the nature of the self. He argues that one's current perspective could be "metaphysically privileged" on the basis of arguments for A-theory being stronger as arguments for both A-theory and a metaphysically privileged self, and arguments against A-theory are ineffective against this combined position.
Philosophy of time
In the paper ''The Personalized A-Theory of Time and Perspective'', Vincent Conitzer connects
A series and B series
In metaphysics, the A series and the B series are two different descriptions of the temporal ordering relation among events. The two series differ principally in their use of tense to describe the temporal relation between events and the resulti ...
theories of time with the metaphysics of first-person perspectives. Conitzer argues that if A-theory is correct, and a given moment of time, i.e. the present, is metaphysically privileged, this implies that a given "I" is also metaphysically privileged in the same way. He argues that arguments for A-theory are more effective as arguments for the combined position of both A-theory and first-person realism, but that arguments for B-theory are ineffective against the combined position. Within Caspar Hare's theory of
perspectival realism
In Caspar Hare's theory of perspectival realism, there is a defining ''intrinsic'' property that the things that are in perceptual awareness have. Consider seeing object A but not object B. Of course, we can say that the visual experience of A i ...
, Hare points out that arguments in favor of a certain first-person perspective being metaphysically privileged are similar to the arguments made in favor of
presentism. According to presentism, if Event A is happening on
nsert today's date A is ''simply'' happening (right now), not relative to anything. It could be argued that this is similar to solipsism, in which Experience A is ''simply'' present, not relative to anything, as opposed to only being present ''to you''.
Falsifiability and testability
Solipsism is not a
falsifiable hypothesis as described by
Karl Popper
Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the ...
: there does not seem to be an imaginable disproof. According to Popper: a hypothesis that cannot be falsified is not scientific, and a solipsist can observe "the success of sciences" (see also
no miracles argument). 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 (
psychokinesis
Telekinesis () (alternatively called psychokinesis) is a purported psychic ability allowing an individual to influence a physical system without physical interaction. Experiments to prove the existence of telekinesis have historically been cri ...
). 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 that this argument is circular and incoherent. It assumes at the beginning a "construct of a single consciousness" meaning something false, and then tries to manipulate the external world that it just assumed was false. Of course this is an impossible task, but it does not disprove solipsism. It is simply poor reasoning when considering pure idealized logic and that is why
David Deutsch
David Elieser Deutsch ( ; ; born 18 May 1953) is a British physicist at the University of Oxford, often described as the "father of quantum computing". He is a visiting professor in the Department of Atomic and Laser Physics at the Centre for ...
states that when other scientific methods are used also, (not only logic), solipsism is "indefensible", also when using the
simplest explanations:
"If, according to the simplest explanation, an entity is complex and autonomous, then that entity is real."
The method of the typical scientist is naturalist: 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 Deutsch uses this fact to counter-argue: "outer parts" of solipsist, behave independently so they are independent for "narrowly" defined (''conscious'') self.
[Deutsch, David. (1997) '' Fabric of Reality''] 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
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure of arg ...
minimalism
In visual arts, music, and other media, minimalism is an art movement that began in the post-war era in western art. The movement is often interpreted as a reaction to abstract expressionism and modernism; it anticipated contemporary post-mi ...
. 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
Agnosticism is the view or belief that the existence of God, the divine, or the supernatural is either unknowable in principle or unknown in fact. (page 56 in 1967 edition) It can also mean an apathy towards such religious belief and refer t ...
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
In philosophy, Occam's razor (also spelled Ockham's razor or Ocham's razor; ) is the problem-solving principle that recommends searching for explanations constructed with the smallest possible set of elements. It is also known as the principle o ...
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
Explanatory power is the ability of a hypothesis or theory to explain the subject matter effectively to which it pertains. Its opposite is ''explanatory impotence''.
In the past, various criteria or measures for explanatory power have been prop ...
'' is to be preferred. In other words: additional "entities" can pay their way with enhanced explanatory power. So the naturalist can claim that, while their
world view
A worldview (also world-view) or is said to be the fundamental cognitive orientation of an individual or society encompassing the whole of the individual's or society's knowledge, culture, and point of view. However, when two parties view the s ...
is more complex, it is more satisfying as an explanation.
In infants
Some
developmental psychologists
Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis ...
believe that
infant
In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...
s are solipsistic, and that eventually children
infer
Inferences are steps in logical reasoning, moving from premises to logical consequences; etymologically, the word '' infer'' means to "carry forward". Inference is theoretically traditionally divided into deduction and induction, a distinctio ...
that others have experiences much like theirs and reject solipsism.
Hinduism
The earliest reference to solipsism is found in the ideas in
Hindu philosophy
Hindu philosophy or Vedic philosophy is the set of philosophical systems that developed in tandem with the first Hinduism, Hindu religious traditions during the Iron Age in India, iron and Classical India, classical ages of India. In Indian ...
in the
Brihadaranyaka Upanishad
The ''Brihadaranyaka Upanishad'' (, ) is one of the Mukhya Upanishads, Principal Upanishads and one of the first Upanishadic scriptures of Hinduism. A key scripture to various schools of Hinduism, the ''Brihadaranyaka Upanisad'' is tenth in the ...
, dated to early 1st millennium BC. The
Upanishad
The Upanishads (; , , ) are late Vedic and post-Vedic Sanskrit texts that "document the transition from the archaic ritualism of the Veda into new religious ideas and institutions" and the emergence of the central religious concepts of Hind ...
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
Indian philosophy consists of philosophical traditions of the Indian subcontinent. The philosophies are often called darśana meaning, "to see" or "looking at." Ānvīkṣikī means “critical inquiry” or “investigation." Unlike darśan ...
,
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
Gauḍapāda (Sanskrit: गौडपाद; ), also referred as Gauḍapādācārya (Sanskrit: गौडपादाचार्य; "Gauḍapāda the Teacher"), was an early medieval era Hindu philosopher and scholar of the ''Advaita'' Ved ...
. 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 Hinduism, ''Brahman'' (; IAST: ''Brahman'') connotes the highest universal principle, the ultimate reality of the universe.P. T. Raju (2006), ''Idealistic Thought of India'', Routledge, , page 426 and Conclusion chapter part XII In the ...
, in which Brahman, the universe and the
Atman or the Self, were one and the same.
The concept of the
Self
In philosophy, the self is an individual's own being, knowledge, and values, and the relationship between these attributes.
The first-person perspective distinguishes selfhood from personal identity. Whereas "identity" is (literally) same ...
in the philosophy of Advaita could be interpreted as solipsism. However, the theological definition 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.
It is mentioned in Yoga Vasistha that “…..according to them (we can safely assume that them are present Solipsists) this world is mental in nature. There is no reality other than the ideas of one’s own mind. This view is incorrect, because the world cannot be the content of an individual’s mind. If it were so, an individual would have created and destroyed the world according to his whims. This theory is called atma khyati – the pervasion of the little self (intellect). Yoga Vasistha - Nirvana Prakarana - Uttarardha (Volume - 6) Page 107 by Swami Jyotirmayananda
Samkhya and Yoga
Samkhya
Samkhya or Sankhya (; ) is a dualistic orthodox school of Hindu philosophy. It views reality as composed of two independent principles, '' Puruṣa'' ('consciousness' or spirit) and '' Prakṛti'' (nature or matter, including the human mind a ...
philosophy, which is sometimes seen as the basis of
Yogic
Yoga (UK: , US: ; 'yoga' ; ) is a group of physical, mental, and spiritual practices or disciplines that originated with its own philosophy in ancient India, aimed at controlling body and mind to attain various salvation goals, as pra ...
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
Prakriti ( ) is "the original or natural form or condition of anything, original or primary substance". It is a key concept in Hinduism, formulated by the ''Samkhya'' school, where it does not refer merely to matter or nature, but includes all cog ...
(matter) and
Purusha
''Purusha'' (, ʊɾʊʂᵊ ) is a complex concept whose meaning evolved in Vedic and Upanishadic times. Depending on source and historical timeline, it means the cosmic being or self, awareness, and universal principle.Karl Potter, Presupposit ...
(consciousness).
Buddhism
Some philosophical tenets of
Buddhism
Buddhism, also known as Buddhadharma and Dharmavinaya, is an Indian religion and List of philosophies, philosophical tradition based on Pre-sectarian Buddhism, teachings attributed to the Buddha, a wandering teacher who lived in the 6th or ...
assert that external reality is an
illusion
An illusion is a distortion of the senses, which can reveal how the mind normally organizes and interprets sensory stimulation. Although illusions distort the human perception of reality, they are generally shared by most people.
Illusions may ...
, and can be understood as metaphysical solipsism, but most tenets of
Buddhist philosophy
Buddhist philosophy is the ancient Indian Indian philosophy, philosophical system that developed within the religio-philosophical tradition of Buddhism. It comprises all the Philosophy, philosophical investigations and Buddhist logico-episte ...
, generally hold that the mind and external phenomena are both 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.
Mahāyāna
Mahāyāna ( ; , , ; ) is a term for a broad group of Buddhist traditions, Buddhist texts#Mahāyāna texts, texts, Buddhist philosophy, philosophies, and practices developed in ancient India ( onwards). It is considered one of the three main ex ...
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
Madhyamaka ("middle way" or "centrism"; ; ; Tibetic languages, Tibetan: དབུ་མ་པ་ ; ''dbu ma pa''), otherwise known as Śūnyavāda ("the Śūnyatā, emptiness doctrine") and Niḥsvabhāvavāda ("the no Svabhava, ''svabhāva'' d ...
thought), external objects do exist, but are devoid of any type of inherent identity: "Just as objects of mind do not exist
nherently mind also does not exist
nherently. 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, and exist because of imputation of a name upon a phenomenon, though the phenomenon can function.
The
Yogacara
Yogachara (, IAST: ') is an influential tradition of Buddhist philosophy and psychology emphasizing the study of cognition, perception, and consciousness through the interior lens of meditation, as well as philosophical reasoning (hetuvidyā). ...
(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 (
Prajñakaragupta,
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.
Criticism
Solipsism as radical subjective idealism has often been criticized by well-known philosophers ("solipsism can only succeed in a madhouse" —
A. Schopenhauer, "solipsism is madness" —
M. Gardner.)
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British philosopher, logician, mathematician, and public intellectual. He had influence on mathematics, logic, set theory, and various areas of analytic ...
wrote that it was "psychologically impossible" to believe, "I once received a letter from an eminent logician, Mrs.
Christine Ladd-Franklin
Christine Ladd-Franklin (December 1, 1847 – March 5, 1930) was an American psychologist, logician, and mathematician.
Early life and education
Christine Ladd, sometimes known by the nickname "Kitty", was born on December 1, 1847, in Winds ...
, saying that she was a solipsist, and was surprised that there were no others. Coming from a logician and a solipsist, her surprise surprised me". He also argues that the logic of solipsism compels you to believe in 'solipsism of the moment' where only the presently existing moment can be said to exist.
John Stuart Mill
John Stuart Mill (20 May 1806 – 7 May 1873) was an English philosopher, political economist, politician and civil servant. One of the most influential thinkers in the history of liberalism and social liberalism, he contributed widely to s ...
wrote that one can know of others' minds because "First, they have bodies like me, which I know in my own case, to be the antecedent condition of feelings; and because, secondly, they exhibit the acts, and outward signs, which in my own case I know by experience to be caused by feelings".
See also
* Heinlein's
World as Myth
*
Alfred Binet
Alfred Binet (; ; 8 July 1857 – 18 October 1911), born Alfredo Binetti, was a French psychologist who together with Théodore Simon invented the first practical intelligence test, the Binet–Simon test. In 1904, Binet took part in a comm ...
– The mind and the brain
*
Anathema
The word anathema has two main meanings. One is to describe that something or someone is being hated or avoided. The other refers to a formal excommunication by a Christian denomination, church. These meanings come from the New Testament, where a ...
*
Antiscience
Antiscience is a set of attitudes and a form of anti-intellectualism that involves a rejection of science and the scientific method. People holding antiscientific views do not accept science as an objective method that can generate universal k ...
*
Aseity
Aseity (from Latin "from" and "self", plus '' -ity'') (self-existence, self-causation, self-causality and autocausality) is the property by which a being exists of and from itself. It refers to the monotheistic belief that God does not depend o ...
*
Boltzmann brain
The Boltzmann brain thought experiment suggests that it is probably more likely for a brain to spontaneously form, complete with a memory of having existed in our universe, rather than for the entire universe to come about in the manner cosmolo ...
*
Cartesian doubt
Cartesian doubt is a form of methodological skepticism associated with the writings and methodology of René Descartes (March 31, 1596February 11, 1650). Cartesian doubt is also known as Cartesian skepticism, methodic doubt, methodological skeptic ...
*
Centered world
A centered world, according to David Kellogg Lewis, consists of (1) a possible world, (2) an agent in that world, and (3) a time in that world. The concept of centered worlds has epistemic as well as metaphysical uses; for the latter, the three ...
*
Cognitive closure (philosophy)
*
Consensus reality
Consensus reality refers to the generally agreed-upon version of reality within a community or society, shaped by shared experiences and understandings. This understanding arises from the inherent differences in individual perspectives or subjec ...
*
Dream argument
The dream argument is the postulation that the act of dreaming provides preliminary evidence that the senses we trust to distinguish reality from illusion should not be fully trusted, and therefore, any state that is dependent on our senses sho ...
*
Ethical solipsism
*
Existential nihilism
Existential nihilism is the philosophical theory that life has no objective meaning or purpose.Veit, W. (2018). Existential Nihilism: The Only Really Serious Philosophical Problem – Journal of Camus Studies 2018: 211–236. https://doi.org/10 ...
*
Externism
*
False awakening
*
Immaterialism
*
LaVeyan Satanism
*
Metaphysical nihilism
Metaphysical nihilism is the philosophical theory that there ''might'' have been no objects at all—that is, that there is a possible world in which there are no objects at all; or at least that there might have been no ''concrete'' objects at ...
*
Mind over matter
*
Model-dependent realism
Model-dependent realism is a view of scientific inquiry that focuses on the role of scientific models of phenomena. It claims reality should be interpreted based upon these models, and where several models overlap in describing a particular subject ...
*
Object permanence
Object permanence is the understanding that whether an object can be sensed has no effect on whether it continues to exist. This is a fundamental concept studied in the field of developmental psychology, the subfield of psychology that addres ...
*
Objective idealism
Objective idealism is a philosophical theory that affirms the ideal and spiritual nature of the world and conceives of the idea of which the world is made as the objective and rational form in reality rather than as subjective content of the mind ...
*
Open individualism
Open individualism is a view within the philosophy of self, according to which there exists only one numerically identical subject, who is everyone at all times; in the past, present and future. It is a theoretical solution to the question of ...
*
Panpsychism
In philosophy of mind, panpsychism () is the view that the mind or a mind-like aspect is a fundamental and ubiquitous feature of reality. It is also described as a theory that "the mind is a fundamental feature of the world which exists throug ...
*
Personal horizon
Personal horizon is a concept developed by J. J. Valberg in his book ''Dream, Death and the Self.'' He attempts to bring out his subject-matter by considering the dream hypothesis – what if ''this'' were a dream? In Valberg's view, an undetermi ...
*
Phaneron
The phaneron (From , meaning 'visible, manifest')Note that is the neuter nominative form (see e.g. on Wiktionary) is the subject matter of phenomenology, or of what Charles Sanders Peirce
Charles Sanders Peirce ( ; September 10, 1839 – ...
*
Phenomenalism
In metaphysics, phenomenalism is the view that physical objects cannot justifiably be said to exist as " things-in-themselves", but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in t ...
*
Philosophical realism
Philosophical realismusually not treated as a position of its own but as a stance towards other subject mattersis the view that a certain kind of thing (ranging widely from abstract objects like numbers to moral statements to the physical world ...
*
Primary/secondary quality distinction – John Locke's response to solipsism
*
Problem of other minds
The problem of other minds is a Philosophy, philosophical problem traditionally stated as the following Epistemology, epistemological question: "Given that I can only observe the behavior of others, how can I know that others have minds?" The pr ...
*
Protagoras of Abdera
*
Qualia
In philosophy of mind, qualia (; singular: quale ) are defined as instances of subjective, conscious experience. The term ''qualia'' derives from the Latin neuter plural form (''qualia'') of the Latin adjective '' quālis'' () meaning "of what ...
*
Solipsism syndrome
*
Standpoint theory
*
Stream of consciousness
In literary criticism, stream of consciousness is a narrative mode or method that attempts "to depict the multitudinous thoughts and feelings which pass through the mind" of a narrator. It is usually in the form of an interior monologue which ...
*
Subjectivity
The distinction between subjectivity and objectivity is a basic idea of philosophy, particularly epistemology and metaphysics. Various understandings of this distinction have evolved through the work of countless philosophers over centuries. One b ...
*
''The Egg''
*
The Truman Show delusion
*
Vertiginous question
Benj Hellie's vertiginous question asks why, of all the subjects of experience out there, ''this'' one—the one corresponding to the human being referred to as Benj Hellie—is the one whose experiences are ''lived''? (The reader is supposed to ...
References
Further reading
*
* This book presents an intriguing and scientifically based updating of solipsism involving the latest findings in quantum physics, neurology and consciousness studies.
*
*
*
*
*
*
*
*
*
*
*
{{DEFAULTSORT:Solipsism
Egoism
Epistemological theories
Idealism
Metaphysics of mind
Theory of mind