The Latin cogito, ergo sum, usually translated into English as "I think, therefore I am", is the "first principle" of René Descartes' philosophy. He originally published it in French as je pense, donc je suis in his 1637 Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It later appeared in Latin in his Principles of Philosophy, and a similar phrase (Ego sum, ego existo, 'I am, I exist') also featured prominently in his Meditations on First Philosophy. The dictum is also sometimes referred to as the cogito. As Descartes explained in a margin note, "we cannot doubt of our existence while we doubt." In the posthumously published The Search for Truth by Natural Light, he expressed this insight as dubito, ergo sum, vel, quod idem est, cogito, ergo sum ("I doubt, therefore I am—or what is the same—I think, therefore I am.").Antoine Léonard Thomas, in a 1765 essay in honor of Descartes, presented it as dubito, ergo cogito, ergo sum ("I doubt, therefore I think, therefore I am.").
Descartes's statement became a fundamental element of Western philosophy, as it purported to provide a certainfoundation for knowledge in the face of radical doubt.
While other knowledge could be a figment of imagination, deception, or
mistake, Descartes asserted that the very act of doubting one's own
existence served—at minimum—as proof of the reality of one's own mind;
there must be a thinking entity—in this case the self—for there to be a thought.
One critique of the dictum, first suggested by Pierre Gassendi,
is that it presupposes that there is an "I" which must be doing the
thinking. According to this line of criticism, the most that Descartes
was entitled to say was that "thinking is occurring", not that "I am
thinking".
In Descartes's writings
Descartes first wrote the phrase in French in his 1637 Discourse on the Method. He referred to it in Latin without explicitly stating the familiar form of the phrase in his 1641 Meditations on First Philosophy. The earliest written record of the phrase in Latin is in his 1644 Principles of Philosophy,
where, in a margin note (see below), he provides a clear explanation of
his intent: "[W]e cannot doubt of our existence while we doubt". Fuller
forms of the phrase are attributable to other authors.
Discourse on the Method
The phrase first appeared (in French) in Descartes's 1637 Discourse on the Method in the first paragraph of its fourth part:
Ainsi, à cause que
nos sens nous trompent quelquefois, je voulus supposer qu'il n'y avait
aucune chose qui fût telle qu'ils nous la font imaginer; Et parce qu'il y
a des hommes qui se méprennent en raisonnant, même touchant les plus
simples matières de Géométrie, et y font des Paralogismes, jugeant que
j'étais sujet à faillir autant qu'aucun autre, je rejetai comme fausses
toutes les raisons que j'avais prises auparavant pour Démonstrations; Et
enfin, considérant que toutes les mêmes pensées que nous avons étant
éveillés nous peuvent aussi venir quand nous dormons, sans qu'il y en
ait aucune raison pour lors qui soit vraie, je me résolus de feindre que
toutes les choses qui m'étaient jamais entrées en l'esprit n'étaient
non plus vraies que les illusions de mes songes. Mais aussitôt après je
pris garde que, pendant que je voulais ainsi penser que tout était faux,
il fallait nécessairement que moi qui le pensais fusse quelque chose;
Et remarquant que cette vérité, je pense,donc je suis, était si ferme et si assurée, que toutes les plus extravagantes
suppositions des Sceptiques n'étaient pas capables de l'ébranler, je
jugeai que je pouvais la recevoir sans scrupule pour le premier principe
de la Philosophie que je cherchais.
Translation:
Accordingly, seeing that our senses sometimes deceive us, I was
willing to suppose that there existed nothing really such as they
presented to us; And because some men err in reasoning, and fall into Paralogisms,
even on the simplest matters of Geometry, I, convinced that I was as
open to error as any other, rejected as false all the reasonings I had
hitherto taken for Demonstrations; And finally, when I considered that
the very same thoughts (presentations) which we experience when awake
may also be experienced when we are asleep, while there is at that time
not one of them true, I supposed that all the objects (presentations)
that had ever entered into my mind when awake, had in them no more truth
than the illusions of my dreams. But immediately upon this I observed
that, whilst I thus wished to think that all was false, it was
absolutely necessary that I, who thus thought, should be something; And
as I observed that this truth, I think,therefore I am, was so certain and of such evidence that no ground of doubt, however
extravagant, could be alleged by the Sceptics capable of shaking it, I
concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search.
Meditations on First Philosophy
In 1641, Descartes published (in Latin) Meditations on first philosophy in which he referred to the proposition, though not explicitly as "cogito, ergo sum" in Meditation II:
hoc pronuntiatum: Ego sum, Ego existo, quoties a me profertur, vel mente concipitur, necessario esse verum.
Translation:
this proposition: I am, I exist, whenever it is uttered by me, or conceived by the mind, necessarily is true.
In Response to an Objection from Marin Mersenne, he wrote "cogito, ergo sum” in an extended form and, again, prefaced with ‘ego’:
Cum advertimus nos esse res cogitantes, prima quædam notio est quæ ex nullo syllogismo concluditur; neque etiam cum quis dicit ‘ego cogito, ergo sum, sive existo,’ existentiam ex cogitatione per syllogismum deducit, sed tanquam rem per se notam simplici mentis intuitu agnoscit.
Translation:
And when we become aware that we are thinking things, this is a
primary notion which is not derived by means of any syllogism. When
someone says 'I am thinking, therefore I am, or I exist’ he does not deduce existence from thought by means of a syllogism, but
recognizes it as something self-evident by a simple intuition of the
mind.
Principles of Philosophy
In 1644, Descartes published (in Latin) his Principles of Philosophy which begins Veritatem inquirenti semel in vita da omnibus, quantum fieri potest, esse dubitandum. (That in order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things.) The phrase "ego cogito, ergo sum" appears in Part 1, article 7:
"ego cogito, ergo sum" with margin note in original (1644) Principia Philosophae
Sic autem
rejicientes illa omnia, de quibus aliquo modo possumus dubitare, ac
etiam, falsa esse fingentes, facilè quidem, supponimus nullum esse Deum,
nullum coelum, nulla corpora; nosque etiam ipsos, non habere manus, nec
pedes, nec denique ullum corpus, non autem ideò nos qui talia cogitamus
nihil esse: repugnat enim ut putemus id quod cogitat eo ipso tempore
quo cogitat non existere. Ac proinde haec cognitio, ego cogito, ergo sum, est omnium prima & certissima, quae cuilibet ordine philosophanti occurrat.
Translation:
While we thus reject all of which we can entertain the smallest
doubt, and even imagine that it is false, we easily indeed suppose that
there is neither God, nor sky, nor bodies, and that we ourselves even
have neither hands nor feet, nor, finally, a body; but we cannot in the
same way suppose that we are not while we doubt of the truth of these
things; for there is a repugnance in conceiving that what thinks does
not exist at the very time when it thinks. Accordingly, the knowledge, I think, therefore I am, is the first and most certain that occurs to one who philosophizes orderly.
Descartes's margin note for the above paragraph is:
Non posse à nobis dubitari, quin existamus dum dubitamus; atque hoc esse primum, quod ordine philosophando cognoscimus.
Translation:
That we cannot doubt of our existence while we doubt, and that this
is the first knowledge we acquire when we philosophize in order.
The Search for Truth by Natural Light
Descartes, in a lesser-known posthumously published work written ca. 1647, originally in French with the title La Recherche de la Vérité par La Lumiere Naturale (The Search for Truth by Natural Light) and later in Latin with the title Inquisitio Veritatis per Lumen Naturale, provides his only known phrasing of the cogito as cogito, ergo sum and admits that his insight is also expressible as dubito, ergo sum:
"dubito, ergo sum, vel, quod idem est, cogito, ergo sum" in Inquisitio Veritatis per Lumen Naturale
... [S]entio,
oportere, ut quid dubitatio, quid cogitatio, quid exsistentia sit antè
sciamus, quàm de veritate hujus ratiocinii: dubito, ergo sum, vel, quod idem est, cogito, ergo sum : plane simus persuasi.
Translation:
… [I feel that] it is necessary to know what doubt is, and what
thought is, [what existence is], before we can be fully persuaded of
this reasoning — I doubt, therefore I am — or what is the same — I think, therefore I am.
"ego cogito, ergo sum" or "cogito, ergo sum"?
Peter
J. Markie notes: "Descartes stresses the first person in his premise
twice in the Principles and once in his Reply to Mersenne. ego cogito, ergo sum
. . . . (AT VIII, 7; AT VIII, 8; AT VII, 140)" and adds "It is unlikely
that Descartes would stress the first person in his premise, if he
wanted us to read the premise as 'Thought is taking place' rather than
'I think.'" Gary Hatfield writes: "[I]n Latin the first-person voice need not be
expressed through a separate pronoun, but may be included in the verb
form; nonetheless, Descartes used the Latin first-person pronoun ego more than thirty times in the six Meditations."
Other forms
The proposition is sometimes given as dubito, ergo cogito, ergo sum. This form was penned by the French literary critic, Antoine Léonard Thomas, in an award-winning 1765 essay in praise of Descartes, where it appeared as "Puisque je doute, je pense; puisque je pense, j'existe"
('Since I doubt, I think; since I think, I exist'). With rearrangement
and compaction, the passage translates to "I doubt, therefore I think,
therefore I am," or in Latin, "dubito, ergo cogito, ergo sum." This aptly captures Descartes's intent as expressed in his posthumously published La Recherche de la Vérité par La Lumiere Naturale as noted above: I doubt, therefore I am – or what is the same – I think, therefore I am.
A further expansion, dubito, ergo cogito, ergo sum—res cogitans ("…—a thinking thing") extends the cogito with Descartes's statement in the subsequent Meditation, "Ego
sum res cogitans, id est dubitans, affirmans, negans, pauca
intelligens, multa ignorans, volens, nolens, imaginans etiam et
sentiens…" ("I am a thinking [conscious] thing, that is, a
being who doubts, affirms, denies, knows a few objects, and is ignorant
of many, [who loves, hates,] wills, refuses, who imagines likewise, and perceives"). This has been referred to as "the expanded cogito."
Translation
"I am thinking" vs. "I think"
While the Latin cōgitō may be translated rather easily as "I think/ponder/visualize", je pense does not indicate whether the verb form corresponds to the English simple present ("think") or progressive aspect ("is thinking"). Following John Lyons (1982), Vladimir Žegarac notes, "The temptation to use the simple present is
said to arise from the lack of progressive forms in Latin and French,
and from a misinterpretation of the meaning of cogito as habitual or generic" (cf. gnomic aspect). Also following Lyons, Ann Banfield
writes, "In order for the statement on which Descartes's argument
depends to represent certain knowledge,… its tense must be a true
present—in English, a progressive,… not as 'I think' but as 'I am
thinking, in conformity with the general translation of the Latin or
French present tense in such nongeneric, nonstative contexts." Or in the words of Simon Blackburn,
"Descartes's premise is not 'I think' in the sense of 'I ski', which
can be true even if you are not at the moment skiing. It is supposed to
be parallel to 'I am skiing'."
The similar translation "I am thinking, therefore I exist" of Descartes's correspondence in French ("je pense, donc je suis") appears in The Philosophical Writings of Descartes by Cottingham et al. (1988).
The earliest known translation as "I am thinking, therefore I am" is from 1872 by Charles Porterfield Krauth.
Fumitaka Suzuki writes "Taking consideration of Cartesian theory
of continuous creation, which theory was developed especially in the
Meditations and in the Principles, we would assure that 'I am thinking,
therefore I am/exist' is the most appropriate English translation of
'ego cogito, ergo sum'."
"I exist" vs. "I am"
Alexis Deodato S. Itao notes that cogito, ergo sum is "literally 'I think, therefore I am'." Others differ: 1) "[A] precise English translation will read as 'I am thinking, therefore I exist'; and 2) "[S]ince Descartes ... emphasized that existence is such an
important 'notion,' a better translation is 'I am thinking, therefore I
exist.'"
Punctuation
Descartes wrote this phrase as such only once, in the posthumously published lesser-known work noted above, The Search for Truth by Natural Light. It appeared there mid-sentence, uncapitalized, and with a comma. (Commas were not used in Classical Latin but were a regular feature of scholastic Latin, the Latin Descartes "had learned in a Jesuit college at La Flèche.") Most modern reference works show it with a comma, but it is often
presented without a comma in academic work and in popular usage. In
Descartes's Principia Philosophiae, the proposition appears as ego cogito, ergo sum.
Interpretation
As put succinctly by Krauth (1872), "That cannot doubt which does not think, and that cannot think which does not exist. I doubt, I think, I exist."
The phrase cogito, ergo sum is not used in Descartes's Meditations on First Philosophy, but the term "the cogito" is used to refer to an argument from it. In the Meditations, Descartes phrases the conclusion of the argument as "that the proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind" (Meditation II). George Henry Lewes
says Descartes "has told us that [his objective] was to find a starting
point from which to reason—to find an irreversible certainty. And where
did he find this? In his own consciousness. Doubt as I may, I cannot
doubt of my own existence, because my very doubts reveal to me a
something which doubts. You may call this an assumption, if you will; I
point out the fact as one above and beyond all logic; which logic can
neither prove nor disprove; but which must always remain an irreversible
certainty, and as such a fitting basis of philosophy."
At the beginning of the second meditation, having reached what he
considers to be the ultimate level of doubt—his argument from the
existence of a deceiving god—Descartes examines his beliefs to see if
any have survived the doubt. In his belief in his own existence, he
finds that it is impossible to doubt that he exists. Even if there were
a deceiving god (or an evil demon),
one's belief in their own existence would be secure, for there is no
way one could be deceived unless one existed in order to be deceived.
But I have convinced myself that
there is absolutely nothing in the world, no sky, no earth, no minds, no
bodies. Does it now follow that I, too, do not exist? No. If I
convinced myself of something [or thought anything at all], then I
certainly existed. But there is a deceiver of supreme power and cunning
who deliberately and constantly deceives me. In that case, I, too,
undoubtedly exist, if he deceives me; and let him deceive me as much as
he can, he will never bring it about that I am nothing, so long as I
think that I am something. So, after considering everything very
thoroughly, I must finally conclude that the proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind. (AT VII 25; CSM II 16–17)
There are three important notes to keep in mind here. First, he claims only the certainty of his own
existence from the first-person point of view — he has not proved the
existence of other minds at this point. This is something that has to be
thought through by each of us for ourselves, as we follow the course of
the meditations. Second, he does not say that his existence is
necessary; he says that if he thinks, then necessarily he exists (see the instantiation principle).
Third, this proposition "I am, I exist" is held true not based on a
deduction (as mentioned above) or on empirical induction but on the
clarity and self-evidence of the proposition. Descartes does not use
this first certainty, the cogito, as a foundation upon which to
build further knowledge; rather, it is the firm ground upon which he can
stand as he works to discover further truths. As he puts it:
Archimedes
used to demand just one firm and immovable point in order to shift the
entire earth; so I too can hope for great things if I manage to find
just one thing, however slight, that is certain and unshakable. (AT VII
24; CSM II 16)
According to many Descartes specialists, including Étienne Gilson,
the goal of Descartes in establishing this first truth is to
demonstrate the capacity of his criterion — the immediate clarity and
distinctiveness of self-evident propositions — to establish true and
justified propositions despite having adopted a method of generalized
doubt. As a consequence of this demonstration, Descartes considers
science and mathematics to be justified to the extent that their
proposals are established on a similarly immediate clarity,
distinctiveness, and self-evidence that presents itself to the mind. The
originality of Descartes's thinking, therefore, is not so much in
expressing the cogito—a feat accomplished by other predecessors, as we shall see—but on using the cogito
as demonstrating the most fundamental epistemological principle, that
science and mathematics are justified by relying on clarity,
distinctiveness, and self-evidence.
Baruch Spinoza in "Principia philosophiae cartesianae" at its Prolegomenon identified "cogito ergo sum" the "ego sum cogitans" (I am a thinking being) as the thinking substance with his ontological interpretation.
Predecessors
Although the idea expressed in cogito, ergo sum is widely attributed to Descartes, he was not the first to mention it. In the late sixth or early fifth century BC, Parmenides is quoted as saying "For to be aware and to be are the same". (Fragment B3) Plato spoke about the "knowledge of knowledge" (Greek: νόησις νοήσεως, nóesis noéseos) and Aristotle explains the idea in full length:
But
if life itself is good and pleasant…and if one who sees is conscious
that he sees, one who hears that he hears, one who walks that he walks
and similarly for all the other human activities there is a faculty that
is conscious of their exercise, so that whenever we perceive, we are
conscious that we perceive, and whenever we think, we are conscious that
we think, and to be conscious that we are perceiving or thinking is to
be conscious that we exist... (Nicomachean Ethics, 1170a 25 ff.)
The Cartesian statement was interpreted to be an Aristotelian syllogism where the premise that all thinkers are also beings is not made explicit.
In the early fifth century AD, Augustine of Hippo in De Civitate Dei
(book XI, 26) affirmed his certain knowledge of his own existence, and
added: "So far as these truths are concerned, I do not at all fear the
arguments of the Academics when they say, What if you are mistaken? For
if I am mistaken, I exist." This formulation (si fallor, sum) is sometimes called the Augustinian cogito. In 1640, Descartes wrote to thank Andreas Colvius (a friend of Descartes's mentor, Isaac Beeckman) for drawing his attention to Augustine:
I am obliged to you for drawing my attention to the passage of St Augustine relevant to my I am thinking, therefore I exist.
I went today to the library of this town to read it, and I do indeed
find that he does use it to prove the certainty of our existence. He
goes on to show that there is a certain likeness of the Trinity in us,
in that we exist, we know that we exist, and we love the existence and
the knowledge we have. I, on the other hand, use the argument to show
that this I which is thinking is an immaterial substance with no
bodily element. These are two very different things. In itself it is
such a simple and natural thing to infer that one exists from the fact
that one is doubting that it could have occurred to any writer. But I am
very glad to find myself in agreement with St Augustine, if only to
hush the little minds who have tried to find fault with the principle.
The 8th century Hindu philosopher Adi Shankara
wrote, in a similar fashion, that no one thinks 'I am not', arguing
that one's existence cannot be doubted, as there must be someone there
to doubt.
Spanish philosopher Gómez Pereira in his 1554 work Antoniana Margarita, wrote "nosco me aliquid noscere, & quidquid noscit, est, ergo ego sum" ('I know that I know something, anyone who knows is, therefore I am').
Critique
Use of "I"
In Descartes, The Project of Pure Enquiry, English philosopher Bernard Williams provides a history and full evaluation of this issue. The first to raise the "I" problem was Pierre Gassendi, who in his Disquisitio Metaphysica, as noted by Saul Fisher, "points out that recognition that one has a
set of thoughts does not imply that one is a particular thinker or
another. …[T]he only claim that is indubitable here is the
agent-independent claim that there is cognitive activity present."
The objection, as presented by Georg Lichtenberg,
is that rather than supposing an entity that is thinking, Descartes
should have said: "thinking is occurring." That is, whatever the force
of the cogito, Descartes draws too much from it; the existence of a thinking thing, the reference of the "I," is more than the cogito can justify. Friedrich Nietzsche
criticized the phrase in that it presupposes that there is an "I", that
there is such an activity as "thinking", and that "I" know what
"thinking" is. He suggested a more appropriate phrase would be "it
thinks" wherein the "it" could be an impersonal subject as in the sentence "It is raining."
Søren Kierkegaard
The Danish philosopher Søren Kierkegaard called the phrase a tautology in his Concluding Unscientific Postscript. He argues that the cogito
already presupposes the existence of "I", and therefore concluding with
existence is logically trivial. Kierkegaard's argument can be made
clearer if one extracts the premise "I think" into the premises "'x'
thinks" and "I am that 'x'", where "x" is used as a placeholder in order
to disambiguate the "I" from the thinking thing.
Here, the cogito has already assumed the "I"'s existence
as that which thinks. For Kierkegaard, Descartes is merely "developing
the content of a concept", namely that the "I", which already exists,
thinks. As Kierkegaard argues, the proper logical flow of argument is that
existence is already assumed or presupposed in order for thinking to
occur, not that existence is concluded from that thinking.
Bernard Williams
Williams
himself claimed that what we are dealing with when we talk of thought,
or when we say "I am thinking," is something conceivable from a third-person perspective—namely objective "thought-events" in the former case, and an objective thinker in the latter. He argues, first, that it is impossible to make sense of "there is thinking" without relativizing it to something.
However, this something cannot be Cartesian egos, because it is
impossible to differentiate objectively between things just on the basis
of the pure content of consciousness. The obvious problem is that,
through introspection, or our experience of consciousness,
we have no way of moving to conclude the existence of any
third-personal fact, to conceive of which would require something above
and beyond just the purely subjective contents of the mind.
Martin Heidegger
As a critic of Cartesian subjectivity, German philosopher Martin Heidegger sought to ground human subjectivity in death as that certainty which individualizes and authenticates our Being (Dasein). As he wrote in 1925 in History of the Concept of Time:
This certainty, that "I myself am, in that I will die," is the basic certainty of Dasein itself. It is a genuine statement of Dasein, while cogito sum
is only the semblance of such a statement. If such pointed formulations
mean anything at all, then the appropriate statement pertaining to
Dasein in its being would have to be sum moribundus [I am in dying], moribundus not as someone gravely ill or wounded, but insofar as I am, I am moribundus. The MORIBUNDUS first gives the SUM its sense.
John Macmurray
The Scottish philosopher John Macmurray rejected the cogito
outright in order to place action at the center of a philosophical
system he entitled the Form of the Personal. "We must reject this, both
as standpoint and as method. If this be philosophy, then philosophy is a
bubble floating in an atmosphere of unreality." The reliance on thought creates an irreconcilable dualism between thought and action in which the unity
of experience is lost, thus dissolving the integrity of our selves and
destroying any connection with reality. In order to formulate a more
adequate cogito, Macmurray proposes the substitution of "I do"
for "I think," ultimately leading to a belief in God as an agent to
whom all persons stand in relation.
Alfred North Whitehead
In Process and Reality,
Whitehead wrote "Descartes in his own philosophy conceives the thinker
as creating the occasional thought. The philosophy of organism inverts
the order, and conceives the thought as a constituent operation in the
creation of the occasional thinker. The thinker is the final end whereby
there is the thought. In this inversion we have the final contrast
between a philosophy of substance and a philosophy of organism."
In popular culture
In the short story, I Have No Mouth, and I Must Scream, by Harlan Ellison,
Gorrister, when asked what 'AM' means, says "At first it meant Allied
Mastercomputer, and then it meant Adaptive Manipulator, and later on it
developed sentience and linked itself up and they called it an Aggressive Menace, but by then it was too late, and finally called itself AM, emerging intelligence, and what it meant was I am ... cogito ergo sum ... I think, therefore I am."
In the Japanese animated television series, Ergo Proxy, a computer virus that affects the autoreivs, the series' version of robots, known as the Cogito virus begins infecting the autoreivs, which is named such due to the fact that it makes the infected conscious, and experience emotions as a human would.
In the video game Honkai: Star Rail, Dr. Ratio (real name Veritas Ratio), a playable character and, according to in-game lore, a philosopher, has a skill, named "Cogito, Ergo Sum".
In the philosophy of mind, the "hard problem" of consciousness is to explain why and how humans (and other organisms) have qualia, phenomenal consciousness, or subjective experience. It is contrasted with the "easy problems" of explaining why and how
physical systems give a human being the ability to discriminate, to
integrate information, and to perform behavioural functions such as
watching, listening, speaking (including generating an utterance that
appears to refer to personal behaviour or belief), and so forth. The easy problems are amenable to functional explanation—that is,
explanations that are mechanistic or behavioural—since each physical
system can be explained purely by reference to the "structure and
dynamics" that underpin the phenomenon.
Proponents of the hard problem propose that it is categorically
different from the easy problems since no mechanistic or behavioural
explanation could explain the character of an experience,
not even in principle. Even after all the relevant functional facts are
explicated, they argue, there will still remain a further question:
"why is the performance of these functions accompanied by experience?" To bolster their case, proponents of the hard problem frequently turn to various philosophical thought experiments, involving philosophical zombies, or inverted qualia, or the ineffability of colour experiences, or the unknowability of foreign states of consciousness, such as the experience of being a bat.
The terms "hard problem" and "easy problems" were coined by the philosopherDavid Chalmers in a 1994 talk given at The Science of Consciousness conference held in Tucson, Arizona. The following year, the main talking points of Chalmers' talk were published in The Journal of Consciousness Studies. The publication gained significant attention from consciousness
researchers and became the subject of a special volume of the journal, which was later published into a book. In 1996, Chalmers published The Conscious Mind, a book-length treatment of the hard problem, in which he elaborated on his core arguments and responded to counterarguments. His use of the word easy is "tongue-in-cheek". As the cognitive psychologistSteven Pinker puts it, they are about as easy as going to Mars
or curing cancer. "That is, scientists more or less know what to look
for, and with enough brainpower and funding, they would probably crack
it in this century."
There are a number of other potential philosophical problems
that are related to the Hard Problem. Ned Block believes that there
exists a "Harder Problem of Consciousness", due to the possibility of
different physical and functional neurological systems potentially
having phenomenal overlap. Another potential philosophical problem which is closely related to Benj Hellie's vertiginous question, dubbed "The Even Harder Problem of Consciousness", refers to why a given individual has their own particular personal identity, as opposed to existing as someone else.
Overview
Cognitive scientist David Chalmers first formulated the hard problem in his paper "Facing up to the problem of consciousness" (1995) and expanded upon it in The Conscious Mind (1996). His works provoked comment. Some, such as philosopher David Lewis and Steven Pinker, have praised Chalmers for his argumentative rigour and "impeccable clarity". Pinker later said, in 2018, "In the end I still think that the hard
problem is a meaningful conceptual problem, but agree with Dennett that
it is not a meaningful scientific problem. No one will ever get a grant
to study whether you are a zombie or whether the same Captain Kirk walks
on the deck of the Enterprise and the surface of Zakdorn. And I agree
with several other philosophers that it may be futile to hope for a
solution at all, precisely because it is a conceptual problem, or, more
accurately, a problem with our concepts." Daniel Dennett and Patricia Churchland,
among others, believe that the hard problem is best seen as a
collection of easy problems that will be solved through further analysis
of the brain and behaviour.
Consciousness is an ambiguous term. It can be used to mean self
consciousness, awareness, the state of being awake, and so on. Chalmers
uses Thomas Nagel's definition of consciousness: "the feeling of what it is like to be something." Consciousness, in this sense, is synonymous with experience.
Chalmers' formulation
.
. .even when we have explained the performance of all the cognitive and
behavioral functions in the vicinity of experience—perceptual
discrimination, categorization, internal access, verbal report—there may
still remain a further unanswered question: Why is the performance of these functions accompanied by experience?
— David Chalmers, Facing up to the problem of consciousness
The problems of consciousness, Chalmers argues, are of two kinds: the easy problems and the hard problem.
Easy problems
The easy problems are amenable to reductive enquiry. They are a logical consequence
of lower-level facts about the world, similar to how a clock's ability
to tell time is a logical consequence of its clockwork and structure, or
a hurricane being a logical consequence of the structures and functions
of certain weather patterns. A clock, a hurricane, and the easy
problems, are all the sum of their parts (as are most things).
The easy problems relevant to consciousness concern mechanistic
analysis of the neural processes that accompany behaviour. Examples of
these include how sensory systems work, how sensory data is processed in
the brain, how that data influences behaviour or verbal reports, the
neural basis of thought and emotion, and so on. They are problems that
can be analysed through "structures and functions".
Hard problem
The hard problem, in contrast, is the problem of why and how those processes are accompanied by experience. It may further include the question of why these processes are
accompanied by this or that particular experience, rather than some
other kind of experience. In other words, the hard problem is the
problem of explaining why certain mechanisms are accompanied by
conscious experience. For example, why should neural processing in the brain lead to the felt
sensations of, say, feelings of hunger? And why should those neural
firings lead to feelings of hunger rather than some other feeling (such
as, for example, feelings of thirst)?
Chalmers argues that it is conceivable that the relevant
behaviours associated with hunger, or any other feeling, could occur
even in the absence of that feeling. This suggests that experience is irreducible to physical systems such as the brain. This is the topic of the next section.
How the easy and hard problems are related
Chalmers
believes that the hard problem is irreducible to the easy problems:
solving the easy problems will not lead to a solution to the hard
problem. This is because the easy problems pertain to the causal
structure of the world while the hard problem pertains to consciousness,
and facts about consciousness include facts that go beyond mere causal
or structural description.
For example, suppose someone were to stub their foot and yelp. In this
scenario, the easy problems are mechanistic explanations that involve
the activity of the nervous system and brain and its relation to the
environment (such as the propagation of nerve signals from the toe to
the brain, the processing of that information and how it leads to
yelping, and so on). The hard problem is the question of why these
mechanisms are accompanied by the feeling of pain, or why these
feelings of pain feel the particular way that they do. Chalmers argues
that facts about the neural mechanisms of pain, and pain behaviours, do
not lead to facts about conscious experience. Facts about conscious
experience are, instead, further facts, not derivable from facts about the brain.
The
hard problem is often illustrated by appealing to the logical
possibility of inverted visible spectra. If there is no logical
contradiction in supposing that one's colour vision could be inverted,
it follows that mechanistic explanations of visual processing do not
determine facts about what it is like to see colours.
An explanation for all of the relevant physical facts about neural
processing would leave unexplained facts about what it is like to feel
pain. This is in part because functions and physical structures of any
sort could conceivably exist in the absence of experience.
Alternatively, they could exist alongside a different set of
experiences. For example, it is logically possible
for a perfect replica of Chalmers to have no experience at all, or for
it to have a different set of experiences (such as an inverted visible
spectrum, so that the blue-yellow red-green axes of its visual field are
flipped).
The same cannot be said about clocks, hurricanes, or other
physical things. In those cases, a structural or functional description
is a complete description. A perfect replica of a clock is a clock, a
perfect replica of a hurricane is a hurricane, and so on. The difference
is that physical things are nothing more than their physical
constituents. For example, water is nothing more than H2O molecules, and understanding everything about H2O
molecules is to understand everything there is to know about water. But
consciousness is not like this. Knowing everything there is to know
about the brain, or any physical system, is not to know everything there
is to know about consciousness. Consciousness, then, must not be purely
physical.
Chalmers's idea contradicts physicalism, sometimes labelled materialism.
This is the view that everything that exists is a physical or material
thing, so everything can be reduced to microphysical things. For
example, the rings of Saturn are a physical thing because they are
nothing more than a complex arrangement of a large number of subatomic
particles interacting in a certain way. According to physicalism,
everything, including consciousness, can be explained by appeal to its
microphysical constituents. Chalmers's hard problem presents a counterexample
to this view and to other phenomena like swarms of birds, since it
suggests that consciousness, and analogously swarms of birds, cannot be
reductively explained by appealing to their physical constituents. Thus,
if the hard problem is a real problem then physicalism must be false,
and if physicalism is true then the hard problem must not be a real
problem.
Though Chalmers rejects physicalism, he is still a naturalist.
Christian List
argues that the existence of first-person perspectives and the
inability for physicalism to answer Hellie's vertiginous question is
evidence against physicalism, since first-personal facts cannot
supervene on physical third-personal facts. List also claims that there exists a "quadrilemma" for metaphysical
theories of consciousness, and that for the metaphysical claims of
first-person realism, non-solipsism, non-fragmentation, and one-world,
at least one of these must be false. List has proposed a model he calls the "many-worlds theory of
consciousness" in order to reconcile the subjective nature of
consciousness without lapsing into solipsism.
Historical precedents
The hard problem of consciousness has scholarly antecedents
considerably earlier than Chalmers. Chalmers himself notes that "a
number of thinkers in the recent and distant past" have "recognised the
particular difficulties of explaining consciousness." He states that all his original 1996 paper contributed to the
discussion was "a catchy name, a minor reformulation of philosophically
familiar points".
Among others, thinkers who have made arguments similar to Chalmers' formulation of the hard problem include Isaac Newton, John Locke, Gottfried Wilhelm Leibniz, John Stuart Mill, and Thomas Henry Huxley. Likewise, Asian philosophers like Dharmakirti and Guifeng Zongmi discussed the problem of how consciousness arises from unconscious matter. The Tattva Bodha, an eighth century text attributed to Adi Shankara from the Advaita Vedanta school of Hinduism, describes consciousness being anubhati, or self-revealing, illuminating all objects of knowledge without itself being a material object.
The mind–body problem is the problem of how the mind and the body
relate. The mind-body problem is more general than the hard problem of
consciousness, since it is the problem of discovering how the mind and
body relate in general, thereby implicating any theoretical framework
that broaches the topic. The hard problem, in contrast, is often
construed as a problem uniquely faced by physicalist or materialist
theories of mind.
The philosopher Thomas Nagel posited in his 1974 paper "What Is It
Like to Be a Bat?" that experiences are essentially subjective
(accessible only to the individual undergoing them—i.e., felt only by
the one feeling them), while physical states are essentially objective
(accessible to multiple individuals). So he argued we have no idea what
it could mean to claim that an essentially subjective state just is
an essentially non-subjective state (i.e., that a felt state is nothing
but a functional state). In other words, we have no idea of what
reductivism amounts to. He believes "every subjective phenomenon is essentially connected with a
single point of view, and it seems inevitable that an objective,
physical theory will abandon that point of view."
In 1983, the philosopher Joseph Levine proposed that there is an explanatory gap between our understanding of the physical world and our understanding of consciousness.
Levine's disputes that conscious states are reducible to neuronal
or brain states. He uses the example of pain (as an example of a
conscious state) and its reduction to the firing of c-fibers
(a kind of nerve cell). The difficulty is as follows: even if
consciousness is physical, it is not clear which physical states
correspond to which conscious states. The bridges between the two levels
of description will be contingent, rather than necessary.
This is significant because in most contexts, relating two scientific
levels of descriptions (such as physics and chemistry) is done with the
assurance of necessary connections between the two theories (for
example, chemistry follows with necessity from physics).
Levine illustrates this with a thought experiment: Suppose that
humanity were to encounter an alien species, and suppose it is known
that the aliens do not have any c-fiber. Even if one knows this, it is
not obvious that the aliens do not feel pain: that would remain an open
question. This is because the fact that aliens do not have c-fibers does
not entail that they do not feel pain (in other words, feelings of pain
do not follow with logical necessity from the firing of c-fibers).
Levine thinks such thought experiments demonstrate an explanatory gap
between consciousness and the physical world: even if consciousness is
reducible to physical things, consciousness cannot be explained in terms
of physical things, because the link between physical things and
consciousness is a contingent link.
Levine does not think that the explanatory gap means that
consciousness is not physical; he is open to the idea that the
explanatory gap is only an epistemological problem for physicalism. In contrast, Chalmers thinks that the hard problem of consciousness does show that consciousness is not physical.
Philosophical zombies are a thought experiment commonly used in discussions of the hard problem. They are hypothetical beings physically identical to humans but that lack conscious experience. Philosophers such as Chalmers, Joseph Levine, and Saul Kripke take
zombies as impossible within the bounds of nature but possible within
the bounds of logic. This would imply that facts about experience are not logically entailed
by the "physical" facts. Therefore, consciousness is irreducible. In
Chalmers' words, "after God (hypothetically) created the world, he had
more work to do." Daniel Dennett, a philosopher of mind, criticised the field's use of "the zombie hunch" which he deems an "embarrassment" that ought to "be dropped like a hot potato".
The knowledge argument, also known as Mary's Room, is another
common thought experiment: A hypothetical neuroscientist named Mary has
lived her whole life in a black-and-white room and has never seen colour
before. She also happens to know everything there is to know about the
brain and colour perception. Chalmers believes that when Mary sees the colour red for the first time, she gains new
knowledge — the knowledge of "what red looks like" — which is distinct
from, and irreducible to, her prior physical knowledge of the brain or
visual system. A stronger form of the knowledge argument claims not merely that Mary would lack subjective knowledge of "what red looks like," but that she would lack knowledge of an objective fact
about the world: namely, "what red looks like," a non-physical fact
that can be learned only through direct experience (qualia). Others,
such as Thomas Nagel, take a "physicalist" position, disagree with the argument in its stronger and/or weaker forms. For example, Nagel
put forward a "speculative proposal" of devising a language that could
"explain to a person blind from birth what it is like to see." The knowledge argument implies that such a language could not exist.
Philosophical responses
David Chalmers' formulation of the hard problem of consciousness provoked considerable debate within philosophy of mind, as well as scientific research.
A
diagram showing the relationship between various views concerning the
relationship between consciousness and the physical world
The hard problem is considered a problem primarily for physicalist
views of the mind (the view that the mind is a physical object or
process), since physical explanations tend to be functional, or
structural. Because of this, some physicalists have responded to the
hard problem by seeking to show that it dissolves upon analysis. Other
researchers accept the problem as real and seek to develop a theory of
consciousness' place in the world that can solve it, by either modifying
physicalism or abandoning it in favour of an alternative ontology (such as panpsychism or dualism).
A third response has been to accept the hard problem as real but deny human cognitive faculties can solve it.
PhilPapers
is an organisation that archives academic philosophy papers and
periodically surveys professional philosophers about their views. It can
be used to gauge professional attitudes towards the hard problem. As of
the 2020 survey results, it seems that the majority of philosophers
(62.42%) agree that the hard problem is real, with a substantial
minority that disagrees (29.76%).
Attitudes towards physicalism also differ among professionals. In
the 2009 PhilPapers survey, 56.5% of philosophers surveyed subscribed
to physicalism and 27.1% of philosophers surveyed rejected physicalism.
16.4% fell into the "other" category. In the 2020 PhilPapers survey, 51.93% of philosophers surveyed
indicated that they "accept or lean towards" physicalism and 32.08%
indicated that they reject physicalism. 6.23% were "agnostic" or
"undecided".
Different solutions have been proposed to the hard problem of
consciousness. The sections below taxonomize the various responses to
the hard problem. The shape of this taxonomy was first introduced by
Chalmers in a 2003 literature review on the topic. The labelling convention of this taxonomy has been incorporated into
the technical vocabulary of analytic philosophy, being used by
philosophers such as Adrian Boutel, Raamy Majeed, Janet Levin, Pete Mandik & Josh Weisberg, Roberto Pereira, and Helen Yetter-Chappell.
Type-A materialism (also known as reductive materialism or a priori physicalism) is a view characterised by a commitment to physicalism
and a full rejection of the hard problem. By this view, the hard
problem either does not exist or is just another easy problem, because
every fact about the mind is a fact about the performance of various
functions or behaviours. So, once all the relevant functions and
behaviours have been accounted for, there will not be any facts left
over in need of explanation. Thinkers who subscribe to type-A materialism include Paul and Patricia Churchland, Daniel Dennett, Keith Frankish, and Thomas Metzinger.
Some type-A materialists believe in the reality of phenomenal
consciousness but believe it is nothing extra in addition to certain
functions or behaviours. This view is sometimes referred to as strong reductionism. Other type-A materialists may reject the existence of phenomenal consciousness entirely. This view is referred to as eliminative materialism or illusionism.
Strong reductionism
Many
philosophers have disputed that there is a hard problem of
consciousness distinct from what Chalmers calls the easy problems of
consciousness. Some among them, who are sometimes termed strong reductionists, hold that phenomenal consciousness (i.e., conscious experience) does exist but that it can be fully understood as reducible to the brain.
Broadly, strong reductionists accept that conscious experience is
real but argue it can be fully understood in functional terms as an
emergent property of the material brain. In contrast to weak reductionists (see above), strong reductionists
reject ideas used to support the existence of a hard problem (that the
same functional organization could exist without consciousness, or that a
blind person who understood vision through a textbook would not know
everything about sight) as simply mistaken intuitions.
A notable family of strong reductionist accounts are the higher-order theories of consciousness. In 2005, the philosopher Peter Carruthers
wrote about "recognitional concepts of experience", that is, "a
capacity to recognize [a] type of experience when it occurs in one's own
mental life," and suggested that such a capacity could explain
phenomenal consciousness without positing qualia. On the higher-order view, since consciousness is a representation, and
representation is fully functionally analysable, there is no hard
problem of consciousness.
The philosophers Glenn Carruthers and Elizabeth Schier said in 2012 that the main arguments for the existence of a hard problem—philosophical zombies, Mary's room, and Nagel's bats—are
only persuasive if one already assumes that "consciousness must be
independent of the structure and function of mental states, i.e. that
there is a hard problem." Hence, the arguments beg the question.
The authors suggest that "instead of letting our conclusions on the
thought experiments guide our theories of consciousness, we should let
our theories of consciousness guide our conclusions from the thought
experiments."
The philosopher Massimo Pigliucci argued in 2013 that the hard problem is misguided, resulting from a "category mistake".aid: "Of course an explanation isn't the same as an experience, but
that's because the two are completely independent categories, like
colors and triangles. It is obvious that I cannot experience what it is
like to be you, but I can potentially have a complete explanation of how
and why it is possible to be you."
In 2017, the philosopher Marco Stango, in a paper on John Dewey's
approach to the problem of consciousness (which preceded Chalmers'
formulation of the hard problem by over half a century), noted that
Dewey's approach would see the hard problem as the consequence of an
unjustified assumption that feelings and functional behaviours are not
the same physical process: "For the Deweyan philosopher, the 'hard
problem' of consciousness is a 'conceptual fact' only in the sense that
it is a philosophical mistake: the mistake of failing to see that the physical can be had as an episode of immediate sentiency."
The philosopher Thomas Metzinger likens the hard problem of consciousness to vitalism, a formerly widespread view in biology which was not so much solved as abandoned. Brian Jonathan Garrett has also argued that the hard problem suffers from flaws analogous to those of vitalism.
The philosopher Peter Hacker
argues that the hard problem is misguided in that it asks how
consciousness can emerge from matter, whereas in fact sentience emerges
from the evolution of living organisms. He states: "The hard problem isn't a hard problem at all. The really
hard problems are the problems the scientists are dealing with. [...]
The philosophical problem, like all philosophical problems, is a
confusion in the conceptual scheme." Hacker's critique extends beyond Chalmers and the hard problem, being
directed against contemporary philosophy of mind and neuroscience more
broadly. Along with the neuroscientist Max Bennett, he has argued that most of contemporary neuroscience remains implicitly dualistic in its conceptualisations and is predicated on the mereological fallacy of ascribing psychological concepts to the brain that can properly be ascribed only to the person as a whole. Hacker further states that "consciousness studies", as it exists today,
is "literally a total waste of time" and that "the conception of
consciousness which they have is incoherent".
Eliminative materialism or eliminativism is the view that many or all of the mental states used in folk psychology (i.e., common-sense ways of discussing the mind) do not, upon scientific examination, correspond to real brain mechanisms. According the 2020 PhilPapers survey, 4.51% of philosophers surveyed subscribe to eliminativism.
This stance has recently taken on the name of illusionism: the view that phenomenal consciousness is an illusion. The term was popularized by the philosopher Keith Frankish. Frankish argues that "illusionism" is preferable to "eliminativism" for
labelling the view that phenomenal consciousness is an illusion. More
substantively, Frankish argues that illusionism about phenomenal
consciousness is preferable to realism about phenomenal consciousness.
He states: "Theories of consciousness typically address the hard
problem. They accept that phenomenal consciousness is real and aim to
explain how it comes to exist. There is, however, another approach,
which holds that phenomenal consciousness is an illusion and aims to
explain why it seems to exist." Frankish concludes that illusionism "replaces the hard problem with the
illusion problem—the problem of explaining how the illusion of
phenomenality arises and why it is so powerful."
The philosopher Daniel Dennett was another prominent figure associated with illusionism. After Frankish published a paper in the Journal of Consciousness Studies titled Illusionism as a Theory of Consciousness, Dennett responded with his own paper humorously titled Illusionism as the Obvious Default Theory of Consciousness. Dennett had been arguing for the illusory status of consciousness since
early on in his career. For example, in 1979 he published a paper
titled On the Absence of Phenomenology (where he argues for the nonexistence of phenomenal consciousness). Similar ideas have been explicated in his 1991 book Consciousness Explained. Dennett argues that the so-called "hard problem" will be solved in the
process of solving what Chalmers terms the "easy problems". He compares consciousness to stage magic and its capability to create extraordinary illusions out of ordinary things. To show how people might be commonly fooled into overstating the
accuracy of their introspective abilities, he describes a phenomenon
called change blindness, a visual process that involves failure to detect scenery changes in a series of alternating images. He accordingly argues that consciousness need not be what it seems to
be based on introspection. To address the question of the hard problem,
or how and why physical processes give rise to experience, Dennett
states that the phenomenon of having experience is nothing more than the
performance of functions or the production of behaviour, which can also
be referred to as the easy problems of consciousness. Thus, Dennett argues that the hard problem of experience is included
among—not separate from—the easy problems, and therefore they can only
be explained together as a cohesive unit.
Eliminativists differ on the role they believe intuitive judgement plays in creating the apparent reality of consciousness. The philosopher Jacy Reese Anthis
is of the position that this issue is born of an overreliance on
intuition, calling philosophical discussions on the topic of
consciousness a form of "intuition jousting". But when the issue is tackled with "formal argumentation" and "precise semantics" then the hard problem will dissolve. The philosopher Elizabeth Irvine, in contrast, can be read as having
the opposite view, since she argues that phenomenal properties (that is,
properties of consciousness) do not exist in our common-sense view of the world.
She states that "the hard problem of consciousness may not be a genuine
problem for non-philosophers (despite its overwhelming obviousness to
philosophers)."
A complete illusionist theory of consciousness must include the description of a mechanism
by which the illusion of subjective experience is had and reported by
people. Various philosophers and scientists have proposed possible
theories. For example, in his book Consciousness and the Social Brain neuroscientist Michael Graziano advocates what he calls attention schema theory,
in which our perception of being conscious is merely an error in
perception, held by brains which evolved to hold erroneous and
incomplete models of their own internal workings, just as they hold
erroneous and incomplete models of their own bodies and of the external
world.
Criticisms
The
main criticisms of eliminative materialism and illusionism hinge on the
counterintuitive nature of the view. Arguments of this form are called Moorean Arguments. A Moorean argument seeks to undermine the conclusion of an argument by asserting that the negation of that conclusion is more certain than the premises of the argument.
The roots of the Moorean Argument against illusionism extend back to Augustine of Hippo
who stated that he could not be deceived regarding his own existence,
since the very act of being deceived secures the existence of a being
there to be the recipient of that deception.
In the Early-Modern era, these arguments were repopularized by René Descartes, who coined the now famous phrase "Je pense, donc je suis" ("I think, therefore I am"). Descartes argued that even if he was maximally deceived (because, for
example, an evil demon was manipulating all his senses) he would still
know with certainty that his mind exists, because the state of being
deceived requires a mind as a prerequisite.
This same general argumentative structure is still in use today.
For example, in 2002 David Chalmers published an explicitly Moorean
argument against illusionism. The argument goes like this: The reality
of consciousness is more certain than any theoretical commitments (to,
for example, physicalism) that may be motivating the illusionist to deny
the existence of consciousness. The reason for this is because we have
direct "acquaintance" with consciousness, but we do not have direct
acquaintance with anything else (including anything that could inform
our beliefs in consciousness being an illusion). In other words:
consciousness can be known directly, so the reality of consciousness is
more certain than any philosophical or scientific theory that says
otherwise. Chalmers concludes that "there is little doubt that something like the
Moorean argument is the reason that most people reject illusionism and
many find it crazy."
Eliminative materialism and illusionism have been the subject of
criticism within the popular press. One highly cited example comes from
the philosopher Galen Strawson who wrote an article in the New York Review of Books
titled "The Consciousness Deniers". In it, Strawson describes
illusionism as the "silliest claim ever made", next to which "every
known religious belief is only a little less sensible than the belief
that the grass is green." Another notable example comes from Christof Koch (a neuroscientist and one of the leading proponents of Integrated Information Theory) in his popular science book The Feeling of Life Itself.
In the early pages of the book, Koch describes eliminativism as the
"metaphysical counterpart to Cotard's syndrome, a psychiatric condition
in which patients deny being alive." Koch takes the prevalence of eliminativism as evidence that "much of
twentieth-century analytic philosophy has gone to the dogs".
Frankish has responded to such criticisms by asserting that
"qualia realists" have to conceive of qualia as being either
observational or theoretical in nature. If conceived of as
observational, then realists cannot claim that illusionists are leaving
anything out of their theories of consciousness, as such a claim would
presuppose qualia as having certain theoretical components. If conceived
of as theoretical, then illusionists are simply denying the theoretical
components of qualia but not the mere fact that they exist, which is
what they're attempting to explain in the first place.
Type-B Materialism, also known as Weak Reductionism or A Posteriori Physicalism, is the view that the hard problem stems from human psychology, and is therefore not indicative of a genuine ontological gap between consciousness and the physical world. Like Type-A Materialists, Type-B Materialists are committed to physicalism. Unlike Type-A Materialists, however, Type-B Materialists do
accept inconceivability arguments often cited in support of the hard
problem, but with a key caveat: that inconceivability arguments give us
insight only into how the human mind tends to conceptualize the relationship between mind and matter, but not into what the true nature of this relationship actually is. According to this view, there is a gap between two ways of knowing
(introspection and neuroscience) that will not be resolved by
understanding all the underlying neurobiology, but still believe that
consciousness and neurobiology are one and the same in reality.
While Type-B Materialists all agree that intuitions about the
hard problem are psychological rather than ontological in origin, they
differ as to whether our intuitions about the hard problem are innate or
culturally conditioned. This has been dubbed the "hard-wired/soft-wired
distinction." In relation to Type-B Materialism, those who believe that our
intuitions about the hard problem are innate (and therefore common to
all humans) subscribe to the "hard-wired view". Those that believe our intuitions are culturally conditioned subscribe
to the "soft-wired view". Unless otherwise specified, the term Type-B Materialism refers to the hard-wired view.
Notable philosophers who subscribe to Type-B Materialism include David Papineau, Joseph Levine, and Janet Levine.
The "hard-wired view"
Joseph Levine (who formulated the notion of the explanatory gap) states: "The explanatory gap argument doesn't demonstrate a gap in nature, but a gap in our understanding of nature." He nevertheless contends that full scientific understanding will not close the gap, and that analogous gaps do not exist for other identities in nature, such as that between water and H2O. The philosophers Ned Block and Robert Stalnaker
agree that facts about what a conscious experience is like to the one
experiencing it cannot be deduced from knowing all the facts about the
underlying physiology, but by contrast argue that such gaps of knowledge
are also present in many other cases in nature, such as the distinction between water and H2O.
To explain why these two ways of knowing (i.e. third-person
scientific observation and first-person introspection) yield such
different understandings of consciousness, weak reductionists often
invoke the phenomenal concepts strategy, which argues the difference stems from our inaccurate phenomenal concepts (i.e., how we think about consciousness), not from the nature of consciousness itself. By this view, the hard problem of consciousness stems from a dualism of
concepts, not from a dualism of properties or substances.
The "soft-wired view"
Some
consciousness researchers have argued that the hard problem is a
cultural artifact, unique to contemporary Western Culture. This is
similar to Type-B Materialism, but it makes the further claim that the
psychological facts that cause us to intuit the hard problem are not
innate, but culturally conditioned. Notable researchers who hold this
view include Anna Wierzbicka, Hakwan Lau and Matthias Michel.
Wierzbicka (who is a linguist) argues that the vocabulary used by consciousness researchers (including words like experience and consciousness) are not universally translatable, and are "parochially English." Weirzbicka calls David Chalmers out by name for using these words,
arguing that if philosophers "were to use panhuman concepts expressed in
crosstranslatable words" (such as know, think, or feel) then the hard problem would dissolve. David Chalmers has responded to these criticisms by saying that he will
not "apologise for using technical terms in an academic article . . .
they play a key role in efficient communication in every discipline,
including Wierzbicka's".
Type-C Materialism
Type-C materialists acknowledge a distinction between knowledge and experience without asserting a more complete explanation for the experiential
phenomenon. One taking this view would admit that there is an explanatory gap for which no answer to date may be satisfactory, but trust that inevitably the gap will be closed. This is described by analogy to progression in other areas of science, such as mass-energy equivalence which would have been unfathomable in ancient times, abiogenesis which was once considered paradoxical from an evolutionary framework, or a suspected future theory of everything
combining relativity and quantum mechanics. Similarly, type-C
materialism posits that the problem of consciousness is a consequence of
our ignorance but just as resolvable as any other question in neuroscience.
Because the explanatory question of consciousness is evaded, type-C materialism does not presuppose the descriptive question, for instance that there is any self-consciousness, wakefulness, or even sentience in a rock. Principally, the basis for the argument arises from the
apparently high correlation of consciousness with living brain tissue, thereby rejecting panpsychism without explicitly formulating physical causation. More specifically this position denies the existence of philosophical zombies for which there is an absence of data and no proposed method of testing. Whether via the inconceivability or actual nonexistence of zombies, a
contradiction is exposed nullifying the premise of the consciousness
problem's "hardness".
Type-C materialism is compatible with several cases and could collapse into one of these other metaphysical views depending on scientific discovery and its interpretation. With evidence of emergence,
it resolves to strong reductionism under type A. With a different,
possibly cultural paradigm for understanding consciousness, it resolves
to type-B materialism. If consciousness is explained by the quantum mind, then it resolves to property dualism under type D. With characterisation of intrinsic properties in physics extending
beyond structure and dynamics, it could resolve to type-F monism.
Richard Brown has defended an unorthodox form of type-C materialism which states that the hard problem cannot be decided a priori
and the two major positions (physicalism and dualism) can only be
vindicated empirically, i.e. through scientific advances. His version of
type-C materialism is unorthodox because he claims that it does not
collapse into the other positions. He uses "reverse zombie" and "reverse
knowledge" thought experiments (anti-dualist versions of the standard
anti-physicalist arguments) to show that a priori arguments beg
the question and are only useful for revealing one's own intuitions,
whether physicalist or dualist. The only reason why such thought
experiments, both anti-physicalist and anti-dualist, seem intuitive is
because they are prima facie conceivable but not ideally
conceivable, where ideal conceivability involves knowledge of the
completed science and thus the ability to deduce a priori the discovered identities, in the same way that "water is H₂O" was discovered empirically but the identity is deducible a priori.
Dualism views consciousness as either a non-physical substance separate from the brain or a non-physical property of the physical brain. Dualism is the view that the mind is irreducible to the physical body. There are multiple dualist accounts of the causal relationship between
the mental and the physical, of which interactionism and
epiphenomenalism are the most common today. Interactionism posits that
the mental and physical causally impact one another, and is associated
with the thought of René Descartes (1596–1650). Epiphenomenalism holds the mental is causally dependent on the physical, but does not in turn causally impact it.
In contemporary philosophy, interactionism has been defended by philosophers including Martine Nida-Rümelin, while epiphenomenalism has been defended by philosophers including Frank Jackson (although Jackson later changed his stance to physicalism). Chalmers has also defended versions of both positions as plausible. Traditional dualists such as Descartes believed the mental and the physical to be two separate substances, or fundamental types of entities (hence "substance dualism"); some more recent dualists, however, accept only one substance, the physical, but state it has both mental and physical properties (hence "property dualism").
Meanwhile, panpsychism and neutral monism, broadly speaking, view consciousness as intrinsic to matter. In its most basic form, panpsychism holds that all physical entities
have minds (though its proponents take more qualified positions), while neutral monism, in at least some variations, holds that entities
are composed of a substance with mental and physical aspects—and is thus
sometimes described as a type of panpsychism.
Forms of panpsychism and neutral monism were defended in the early twentieth century by the psychologist William James, the philosopher Alfred North Whitehead, the physicist Arthur Eddington, and the philosopher Bertrand Russell, and interest in these views has been revived in recent decades by philosophers including Thomas Nagel, Galen Strawson, Philip Goff, and David Chalmers. Chalmers describes his overall view as "naturalistic dualism", but he says panpsychism is in a sense a form of physicalism, as does Strawson. Proponents of panpsychism argue it solves the hard problem of
consciousness parsimoniously by making consciousness a fundamental
feature of reality.
A traditional solution to the hard problem is idealism,
according to which consciousness is fundamental and not simply an
emergent property of matter. It is claimed that this avoids the hard
problem entirely. Objective idealism and cosmopsychism
consider mind or consciousness to be the fundamental substance of the
universe. Proponents claim that this approach is immune to both the hard
problem of consciousness and the combination problem that affects panpsychism.
From an idealist perspective, matter is a representation or image
of mental processes. Supporters suggest that this avoids the problems
associated with the materialist view of mind as an emergent property of a
physical brain. Critics argue that this then leads to a decombination problem: how is
it possible to split a single, universal conscious experience into
multiple, distinct conscious experiences? In response, Bernardo Kastrup
claims that nature hints at a mechanism for this in the condition dissociative identity disorder (previously known as Multiple Personality Disorder). Kastrup proposes dissociation as an example from nature showing that
multiple minds with their own individual subjective experience could
develop within a single universal mind.
Cognitive psychologist Donald D. Hoffman uses a mathematical model based around conscious agents, within a fundamentally conscious universe, to support conscious realism
as a description of nature—one that falls within the objective idealism
approaches to the hard problem: "The objective world, i.e., the world
whose existence does not depend on the perceptions of a particular
conscious agent, consists entirely of conscious agents."
David Chalmers calls this form of idealism one of "the handful of promising approaches to the mind–body problem."
New mysterianism, most significantly associated with the philosopher Colin McGinn, proposes that the human mind, in its current form, will not be able to explain consciousness. McGinn draws on Noam Chomsky's
distinction between problems, which are in principle solvable, and
mysteries, which human cognitive faculties are unequipped to ever
understand, and places the mind–body problem in the latter category. His position is that a naturalistic explanation does exist but that the human mind is cognitively closed to it due to its limited range of intellectual abilities. He cites Jerry Fodor's concept of the modularity of mind in support of cognitive closure.
While in McGinn's strong form, new mysterianism states that the relationship between consciousness and the material world can never
be understood by the human mind, there are also weaker forms that argue
it cannot be understood within existing paradigms but that advances in
science or philosophy may open the way to other solutions (see above). The ideas of Thomas Nagel and Joseph Levine fall into the second category. Steven Pinker has also endorsed this weaker version of the view, summarising it as follows:
And then there is the theory put forward by philosopher
Colin McGinn that our vertigo when pondering the Hard Problem is itself a
quirk of our brains. The brain is a product of evolution, and just as
animal brains have their limitations, we have ours. Our brains can't
hold a hundred numbers in memory, can't visualize seven-dimensional
space and perhaps can't intuitively grasp why neural information
processing observed from the outside should give rise to subjective
experience on the inside. This is where I place my bet, though I admit
that the theory could be demolished when an unborn genius—a Darwin or
Einstein of consciousness—comes up with a flabbergasting new idea that
suddenly makes it all clear to us.
Commentary on the problem's explanatory targets
Philosopher Raamy Majeed argued in 2016 that the hard problem is associated with two "explanatory targets":
[PQ] Physical processing gives rise to experiences with a phenomenal character.
[Q] Our phenomenal qualities are thus-and-so.
The first fact concerns the relationship between the physical and the phenomenal (i.e., how and why are some physical states felt states), whereas the second concerns the very nature of the phenomenal itself (i.e., what does the felt state feel like?).
Wolfgang Fasching argues that the hard problem is not about
qualia, but about the what-it-is-like-ness of experience in Nagel's
sense—about the givenness of phenomenal contents:
Today there is a strong tendency to simply equate
consciousness with the qualia. Yet there is clearly something not quite
right about this. The "itchiness of itches" and the "hurtfulness of
pain" are qualities we are conscious of. So philosophy of mind
tends to treat consciousness as if it consisted simply of the contents
of consciousness (the phenomenal qualities), while it really is
precisely consciousness of contents, the very givenness of
whatever is subjectively given. And therefore the problem of
consciousness does not pertain so much to some alleged "mysterious,
nonpublic objects", i.e. objects that seem to be only "visible" to the
respective subject, but rather to the nature of "seeing" itself (and in
today's philosophy of mind astonishingly little is said about the
latter).
Relationship to scientific frameworks
Most
neuroscientists and cognitive scientists believe that Chalmers' alleged
"hard problem" will be solved, or be shown to not be a real problem, in
the course of the solution of the so-called "easy problems", although a
significant minority disagrees.
Since 1990, researchers including the molecular biologist Francis Crick and the neuroscientist Christof Koch
have made significant progress toward identifying which neurobiological
events occur concurrently to the experience of subjective
consciousness. These postulated events are referred to as neural correlates of consciousness or NCCs. However, this research arguably addresses the question of which neurobiological mechanisms are linked to consciousness but not the question of why
they should give rise to consciousness at all, the latter being the
hard problem of consciousness as Chalmers formulated it. In "On the
Search for the Neural Correlate of Consciousness", Chalmers said he is
confident that, granting the principle that something such as what he
terms "global availability" can be used as an indicator of
consciousness, the neural correlates will be discovered "in a century or
two". Nevertheless, he stated regarding their relationship to the hard problem of consciousness:
One can always ask why these processes of availability
should give rise to consciousness in the first place. As yet we cannot
explain why they do so, and it may well be that full details about the
processes of availability will still fail to answer this question.
Certainly, nothing in the standard methodology I have outlined answers
the question; that methodology assumes a relation between availability
and consciousness, and therefore does nothing to explain it. [...] So
the hard problem remains. But who knows: Somewhere along the line we may
be led to the relevant insights that show why the link is there, and
the hard problem may then be solved.
The neuroscientist and Nobel laureate Eric Kandel
wrote that locating the NCCs would not solve the hard problem, but
rather one of the so-called easy problems to which the hard problem is
contrasted. Kandel went on to note Crick and Koch's suggestion that once the binding problem—understanding what accounts for the unity of experience—is solved, it will be possible to solve the hard problem empirically. However, neuroscientist Anil Seth
argued that emphasis on the so-called hard problem is a distraction
from what he calls the "real problem": understanding the neurobiology
underlying consciousness, namely the neural correlates of various
conscious processes. This more modest goal is the focus of most scientists working on consciousness. Psychologist Susan Blackmore
believes, by contrast, that the search for the neural correlates of
consciousness is futile and itself predicated on an erroneous belief in
the hard problem of consciousness.
A functionalist view in cognitive science holds that the mind is an information processing system, and that cognition and consciousness together are a form of computation. Cognition, distinct from consciousness, is explained by neural computation in the computational theory of cognition. The computational theory of mind asserts that not only cognition, but also phenomenal consciousness or qualia,
are computational. While the computation system is realised by neurons
rather than electronics, in theory it would be possible for artificial
intelligence to be conscious.
Integrated information theory (IIT), developed by the neuroscientist and psychiatrist Giulio Tononi
in 2004 and more recently also advocated by Koch, is one of the most
discussed models of consciousness in neuroscience and elsewhere. The theory proposes an identity
between consciousness and integrated information, with the latter item
(denoted as Φ) defined mathematically and thus in principle measurable. The hard problem of consciousness, write Tononi and Koch, may indeed be intractable when working from matter to consciousness. However, because IIT inverts this relationship and works from
phenomenological axioms to matter, they say it could be able to solve
the hard problem. In this vein, proponents have said the theory goes beyond identifying
human neural correlates and can be extrapolated to all physical systems.
Tononi wrote (along with two colleagues):
While identifying the "neural correlates of
consciousness" is undoubtedly important, it is hard to see how it could
ever lead to a satisfactory explanation of what consciousness is and how
it comes about. As will be illustrated below, IIT offers a way to
analyse systems of mechanisms to determine if they are properly
structured to give rise to consciousness, how much of it, and of which
kind.
As part of a broader critique of IIT, Michael Cerullo suggested that
the theory's proposed explanation is in fact for what he dubs (following
Scott Aaronson)
the "Pretty Hard Problem" of methodically inferring which physical
systems are conscious—but would not solve Chalmers' hard problem. "Even if IIT is correct," he argues, "it does not explain why integrated information generates (or is) consciousness." Chalmers agrees that IIT, if correct, would solve the "Pretty Hard Problem" rather than the hard problem.
Global workspace theory (GWT) is a cognitive architecture and theory of consciousness proposed by the cognitive psychologist Bernard Baars in 1988. Baars explains the theory with the metaphor of a theatre, with conscious processes represented by an illuminated stage. This theatre integrates inputs from a variety of unconscious and
otherwise autonomous networks in the brain and then broadcasts them to
unconscious networks (represented in the metaphor by a broad, unlit
"audience"). The theory has since been expanded upon by other scientists including cognitive neuroscientist Stanislas Dehaene.
In his original paper outlining the hard problem of
consciousness, Chalmers discussed GWT as a theory that only targets one
of the "easy problems" of consciousness. In particular, he said GWT provided a promising account of how
information in the brain could become globally accessible, but argued
that "now the question arises in a different form: why should global
accessibility give rise to conscious experience? As always, this
bridging question is unanswered." J. W. Dalton similarly criticised GWT on the grounds that it provides, at best, an account of the cognitive function of consciousness, and fails to explain its experiential aspect. By contrast, A. C. Elitzur argued: "While [GWT] does not address the
'hard problem', namely, the very nature of consciousness, it constrains
any theory that attempts to do so and provides important insights into
the relation between consciousness and cognition."
For his part, Baars writes (along with two colleagues) that there is no hard problem of explaining qualia
over and above the problem of explaining causal functions, because
qualia are entailed by neural activity and themselves causal. Dehaene, in his 2014 book Consciousness and the Brain, rejected the concept of qualia and argued that Chalmers' "easy problems" of consciousness are actually the hard problems. He further stated that the "hard problem" is based only upon
ill-defined intuitions that are continually shifting as understanding
evolves:
Once our intuitions are educated by cognitive
neuroscience and computer simulations, Chalmers' hard problem will
evaporate. The hypothetical concept of qualia, pure mental experience,
detached from any information-processing role, will be viewed as a
peculiar idea of the prescientific era, much like vitalism...
[Just as science dispatched vitalism] the science of consciousness will
keep eating away at the hard problem of consciousness until it
vanishes.
Meta-problem
In 2018, Chalmers highlighted what he calls the "meta-problem of consciousness", another problem related to the hard problem of consciousness:
The meta-problem of consciousness is (to a first
approximation) the problem of explaining why we think that there is a
[hard] problem of consciousness.
In his "second approximation", he says it is the problem of explaining the behaviour of "phenomenal reports", and the behaviour of expressing a belief that there is a hard problem of consciousness.
Explaining its significance, he says:
Although the meta-problem is strictly speaking an easy
problem, it is deeply connected to the hard problem. We can reasonably
hope that a solution to the meta-problem will shed significant light on
the hard problem. A particularly strong line holds that a solution to
the meta-problem will solve or dissolve the hard problem. A weaker line
holds that it will not remove the hard problem, but it will constrain
the form of a solution.
In other words, the 'strong
line' holds that the solution to the meta-problem would provide an
explanation of our beliefs about consciousness that is independent of
consciousness. That might debunk our beliefs about consciousness, in the
same way that (Chalmers suggests) explaining beliefs about god in
evolutionary terms may provide arguments against theism itself.
In popular culture
Tom Stoppard's play The Hard Problem,
first produced in 2015, is named after the hard problem of
consciousness, which Stoppard defines as having "subjective First Person
experiences".
