In semiotics, a sign is anything that communicates a meaning
that is not the sign itself to the interpreter of the sign. The meaning
can be intentional such as a word uttered with a specific meaning, or
unintentional, such as a symptom being a sign of a particular medical condition. Signs can communicate through any of the senses, visual, auditory, tactile, olfactory, or taste.
Two major theories describe the way signs acquire the ability to
transfer information. Both theories understand the defining property of
the sign as a relation between a number of elements. In the tradition of
semiotics developed by Ferdinand de Saussure
(referred to as semiology) the sign relation is dyadic, consisting only
of a form of the sign (the signifier) and its meaning (the signified).
Saussure saw this relation as being essentially arbitrary (the principle
of semiotic arbitrariness), motivated only by social convention. Saussure's theory has been particularly influential in the study of linguistic signs. The other major semiotic theory, developed by C. S. Peirce, defines the sign as a triadic relation as "something that stands for something, to someone in some capacity"
This means that a sign is a relation between the sign vehicle (the
specific physical form of the sign), a sign object (the aspect of the
world that the sign carries meaning about) and an interpretant (the
meaning of the sign as understood by an interpreter). According to
Peirce signs can be divided by the type of relation that holds the sign
relation together as either icons, indices or symbols. Icons are those signs that signify by means of similarity
between sign vehicle and sign object (e.g. a portrait, or a map),
indices are those that signify by means of a direct relation of
contiguity or causality between sign vehicle and sign object (e.g. a
symptom), and symbols are those that signify through a law or arbitrary
social convention.
Dyadic signs
According to Saussure (1857–1913), a sign is composed of the signifier (signifiant), and the signified (signifié).
These cannot be conceptualized as separate entities but rather as a
mapping from significant differences in sound to potential (correct)
differential denotation. The Saussurean sign exists only at the level of
the synchronic
system, in which signs are defined by their relative and hierarchical
privileges of co-occurrence. It is thus a common misreading of Saussure
to take signifiers to be anything one could speak, and signifieds as
things in the world. In fact, the relationship of language to parole
(or speech-in-context) is and always has been a theoretical problem for
linguistics (cf. Roman Jakobson's famous essay "Closing Statement:
Linguistics and Poetics" et al.).
A famous thesis by Saussure states that the relationship between a
sign and the real-world thing it denotes is an arbitrary one. There is
not a natural relationship between a word and the object it refers to,
nor is there a causal relationship between the inherent properties of
the object and the nature of the sign used to denote it. For example,
there is nothing about the physical quality of paper that requires
denotation by the phonological sequence ‘paper’. There is, however, what
Saussure called ‘relative motivation’: the possibilities of
signification of a signifier are constrained by the compositionality of elements in the linguistic system (cf. Emile Benveniste's
paper on the arbitrariness of the sign in the first volume of his
papers on general linguistics). In other words, a word is only
available to acquire a new meaning if it is identifiably different from all the other words in the language and it has no existing meaning. Structuralism
was later based on this idea that it is only within a given system that
one can define the distinction between the levels of system and use, or
the semantic "value" of a sign.
Triadic signs
Charles Sanders Peirce (1839–1914) proposed a different theory. Unlike Saussure who approached the conceptual question from a study of linguistics and phonology, Peirce, the so-called father of the Pragmatist school
of philosophy, extended the concept of sign to embrace many other
forms. He considered "word" to be only one particular kind of sign, and
characterized sign as any mediational means to understanding.
He covered not only artificial, linguistic, and symbolic signs, but
also all semblances (such as kindred sensible qualities), and all
indicators (such as mechanical reactions). He counted as symbols all
terms, propositions, and arguments whose interpretation is based upon
convention or habit, even apart from their expression in particular
languages. He held that "all this universe is perfused with signs, if it
is not composed exclusively of signs". The setting of Peirce's study of signs is philosophical logic, which he defined as formal semiotic, and characterized as a normative field following esthetics and ethics, as more basic than metaphysics, and as the art of devising methods of research. He argued that, since all thought takes time, all thought is in signs, that all thought has the form of inference (even when not conscious and deliberate),
and that, as inference, "logic is rooted in the social principle",
since inference depends on a standpoint that, in a sense, is unlimited.
The result is a theory not of language in particular, but rather of the
production of meaning, and it rejects the idea of a static relationship
between a sign and what it represents: its object. Peirce believed that signs are meaningful through recursive relationships that arise in sets of three.
Even when a sign represents by a resemblance or factual
connection independent of interpretation, the sign is a sign only
insofar as it is at least potentially interpretable by a mind and
insofar as the sign is a determination of a mind or at least a quasi-mind, that functions as if it were a mind, for example in crystals and the work of bees—the focus here is on sign action in general, not on psychology, linguistics, or social studies (fields Peirce also pursued).
A sign depends on an object in a way that enables (and, in a sense, determines) an interpretation, an interpretant, to depend on the object as the sign depends on the object.
The interpretant, then, is a further sign of the object, and thus
enables and determines still further interpretations, further
interpretant signs. The process, called semiosis,
is irreducibly triadic, Peirce held, and is logically structured to
perpetuate itself. It is what defines sign, object, and interpretant in
general. As Jean-Jacques Nattiez (1990: 7) put it, "the process of referring effected by the sign is infinite."
(Peirce used the word "determine" in the sense not of strict
determinism, but of effectiveness that can vary like an influence.)
Peirce further characterized the three semiotic elements as follows:
Sign (or representamen): that which represents the denoted object (cf. Saussure's "signifier").
Object (or semiotic object): that which the sign represents (or as some put it, encodes). It can be anything thinkable, a law, a fact, or even a possibility (a semiotic object could even be fictional, such as Hamlet); those are partial objects; the total object is the universe of discourse,
the totality of objects in that world to which one attributes the
partial object. For example, perturbation of Pluto's orbit is a sign
about Pluto, but not only about Pluto. The object may be
immediate to the sign, the object as represented in the sign, or
dynamic, the object as it really is, on which the immediate object is founded.
Interpretant (or interpretant sign): a sign's meaning or ramification as formed into a further sign by interpreting (or, as some put it, decoding) the sign. The interpretant may be:
immediate to the sign, a kind of possibility, all that the sign is suited to immediately express, for instance a word's usual meaning;
dynamic, that is, the meaning as formed into an actual effect, for example an individual translation or a state of agitation, or
final or normal, that is, the ultimate meaning that
inquiry taken far enough would be destined to reach. It is a kind of
norm or ideal end, with which an actual interpretant may, at most,
coincide.
Peirce explained that signs mediate between their objects and their
interpretants in semiosis, the triadic process of determination. In
semiosis a first is determined or influenced to be a sign by a second, as its object. The object determines the sign to determine a third as an interpretant. Firstness itself is one of Peirce's three categories of all phenomena,
and is quality of feeling. Firstness is associated with a vague state
of mind as feeling and a sense of the possibilities, with neither
compulsion nor reflection. In semiosis the mind discerns an appearance
or phenomenon, a potential sign. Secondness is reaction or
resistance, a category associated with moving from possibility to
determinate actuality. Here, through experience outside of and
collateral to the given sign or sign system, one recalls or discovers
the object the sign refers to, for example when a sign consists in a
chance semblance of an absent but remembered object. It is through one's
collateral experience that the object determines the sign to determine an interpretant. Thirdness
is representation or mediation, the category associated with signs,
generality, rule, continuity, habit-taking, and purpose. Here one forms
an interpretant expressing a meaning or ramification of the sign about
the object. When a second sign is considered, the initial interpretant
may be confirmed, or new possible meanings may be identified. As each
new sign is addressed, more interpretants, themselves signs, emerge. It
can involve a mind's reading of nature, people, mathematics, anything.
Peirce generalized the communicational idea of utterance and interpretation of a sign, to cover all signs:
Admitting that connected Signs must
have a Quasi-mind, it may further be declared that there can be no
isolated sign. Moreover, signs require at least two Quasi-minds; a Quasi-utterer and a Quasi-interpreter;
and although these two are at one (i.e., are one mind) in the sign
itself, they must nevertheless be distinct. In the Sign they are, so to
say, welded. Accordingly, it is not merely a fact of human
Psychology, but a necessity of Logic, that every logical evolution of
thought should be dialogic.
According to Nattiez, writing with Jean Molino, the tripartite definition of sign, object, and interpretant is based on the "trace" or neutral level,
Saussure's "sound-image" (or "signified", thus Peirce's
"representamen"). Thus, "a symbolic form...is not some 'intermediary' in
a process of 'communication' that transmits the meaning intended by the
author to the audience; it is instead the result of a complex process of creation (the poietic
process) that has to do with the form as well as the content of the
work; it is also the point of departure for a complex process of
reception (the esthesic process that reconstructs a 'message'").
Molino's and Nattiez's diagram:
Poietic Process
Esthesic Process
"Producer"
→
Trace
←
Receiver
(Nattiez 1990, p. 17)
Peirce's theory of the sign therefore offered a powerful analysis of
the signification system, its codes, and its processes of inference and
learning—because the focus was often on natural or cultural context
rather than linguistics, which only analyses usage in slow-time whereas
human semiotic interaction in the real world often has a chaotic blur of
language and signal exchange. Nevertheless, the implication that
triadic relations are structured to perpetuate themselves leads to a
level of complexity not usually experienced in the routine of message
creation and interpretation. Hence, different ways of expressing the
idea have developed.
Classes of triadic signs
By 1903 Peirce came to classify signs by three universal trichotomies dependent on his three categories (quality, fact, habit). He classified any sign:
by what stands as the sign — either (qualisign, also called a tone) a quality — or (sinsign, also called token) an individual fact — or (legisign, also called type) a rule, a habit;
by how the sign stands for its object — either (icon) by its
own quality, such that it resembles the object, regardless of factual
connection and of interpretive rule of reference — or (index) by factual connection to its object, regardless of resemblance and of interpretive rule of reference — or (symbol) by rule or habit of interpreted reference to its object, regardless of resemblance and of factual connection; and
by how the sign stands for its object to its interpretant — either (rheme, also called seme,
such as a term) as regards quality or possibility, as if the sign were a
qualisign, though it can be qualisign, sinsign, or legisign — or (dicisign, also called pheme, such as a proposition) as regards fact, as if the sign were an index, though it can be index or symbol — or (argument, also called delome) as regards rule or habit. This is the trichotomy of all signs as building blocks in an inference process.
Any qualisign is an icon. Sinsigns include some icons and some
indices. Legisigns include some icons, some indices, and all symbols.
Any icon is a rheme. Indices (be they sinsigns or legisigns) include
some rhemes and some dicisigns. Symbols include some rhemes, some
dicisigns, and all arguments.
Because of those classificatory interdependences, the three
trichotomies intersect to form ten (rather than 27) classes of signs.
There are also various kinds of meaningful combination. Signs can be
attached to one another. A photograph is an index with a meaningfully
attached icon. Arguments are composed of dicisigns, and dicisigns are
composed of rhemes. In order to be embodied, legisigns (types) need
sinsigns (tokens) as their individual replicas or instances. A symbol
depends as a sign on how it will be interpreted, regardless of
resemblance or factual connection to its object; but the symbol's
individual embodiment is an index to your experience of the object. A
symbol is instanced by a specialized indexical sinsign. A symbol such as
a sentence in a language prescribes qualities of appearance for its
instances, and is itself a replica of a symbol such as a proposition
apart from expression in a particular language. Peirce covered both
semantic and syntactical issues in his theoretical grammar, as he
sometimes called it. He regarded formal semiotic, as logic, as
furthermore encompassing study of arguments (hypothetical, deductive, and inductive) and inquiry's methods including pragmatism; and as allied to but distinct from logic's pure mathematics.
Peirce sometimes referred to the “ground” of a sign. The ground is the pure abstraction of a quality. A sign's ground is the respect in which the sign represents its object, e.g. as in literal and figurative language. For example, an icon presents a characteristic or quality attributed to an object, while a symbol imputes to an object a quality either presented by an icon or symbolized so as to evoke a mental icon.
Peirce called an icon apart from a label, legend, or other index
attached to it, a "hypoicon", and divided the hypoicon into three
classes: (a) the image, which depends on a simple quality; (b) the diagram, whose internal relations, mainly dyadic or so taken, represent by analogy the relations in something; and (c) the metaphor, which represents the representative character of a sign by representing a parallelism in something else.
A diagram can be geometric, or can consist in an array of algebraic
expressions, or even in the common form "All __ is ___" which is
subjectable, like any diagram, to logical or mathematical
transformations. Peirce held that mathematics is done by diagrammatic
thinking — observation of, and experimentation on, diagrams. Peirce
developed for deductive logic a system of visual existential graphs, which continue to be researched today.
20th-century theories
It
is now agreed that the effectiveness of the acts that may convert the
message into text (including speaking, writing, drawing, music and
physical movements) depends upon the knowledge of the sender. If
the sender is not familiar with the current language, its codes and its
culture, then he or she will not be able to say anything at all, whether
as a visitor in a different language area or because of a medical
condition such as aphasia.
Modern theories deny the Saussurian
distinction between signifier and signified, and look for meaning not
in the individual signs, but in their context and the framework of
potential meanings that could be applied. Such theories assert that
language is a collective memory or cultural history of all the different
ways in which meaning has been communicated, and may to that extent,
constitute all life's experiences (see Louis Hjelmslev). Hjelmslev did not consider the sign to be the smallest semiotic
unit, as he believed it possible to decompose it further; instead, he
considered the "internal structure of language" to be a system of figurae, a concept somewhat related to that of figure of speech, which he considered to be the ultimate semiotic unit.
This position implies that speaking is simply one more form of
behaviour and changes the focus of attention from the text as language,
to the text as a representation of purpose, a functional version of the author's intention. But, once the message has been transmitted, the text exists independently.
Hence, although the writers who co-operated to produce this page
exist, they can only be represented by the signs actually selected and
presented here. The interpretation process in the receiver's mind may
attribute meanings completely different from those intended by the
senders. But, why might this happen? Neither the sender nor the receiver
of a text has a perfect grasp of all language. Each individual's
relatively small stock of knowledge is the product of personal experience and their attitude to learning. When the audience
receives the message, there will always be an excess of connotational
meanings available to be applied to the particular signs in their
context (no matter how relatively complete or incomplete their
knowledge, the cognitive process is the same).
The first stage in understanding the message is therefore, to
suspend or defer judgement until more information becomes available. At
some point, the individual receiver decides which of all possible
meanings represents the best possible fit. Sometimes, uncertainty may
not be resolved, so meaning is indefinitely deferred, or a provisional
or approximate meaning is allocated. More often, the receiver's desire
for closure leads to simple meanings being attributed out of prejudices and without reference to the sender's intentions.
Many postmodernist theorists postulate a complete disconnection of the signifier and the signified. An 'empty' or 'floating signifier'
is variously defined as a signifier with a vague, highly variable,
unspecifiable or non-existent signified. Such signifiers mean different
things to different people: they may stand for many or even any
signifieds; they may mean whatever their interpreters want them to mean.
Example of associations between graphemes and colors that are described more accurately as ideasthesia than as synesthesia
Ideasthesia (alternative spelling ideaesthesia) is a
neuroscientific phenomenon in which activations of concepts (inducers)
evoke perception-like sensory experiences (concurrents). The name comes
from the Ancient Greek ἰδέα (idéa) and αἴσθησις (aísthēsis),
meaning "sensing concepts" or "sensing ideas". The notion was
introduced by neuroscientist Danko Nikolić as an alternative explanation
for a set of phenomena traditionally covered by synesthesia.
While "synesthesia" meaning "union of senses" implies the
association of two sensory elements with little connection to the
cognitive level, empirical evidence indicated that most phenomena linked to synesthesia are in fact induced by semantic representations. That is, the linguistic meaning
of the stimulus is what is important rather than its sensory
properties. In other words, while synesthesia presumes that both the
trigger (inducer) and the resulting experience (concurrent) are of
sensory nature, ideasthesia presumes that only the resulting experience
is of sensory nature while the trigger is semantic.
Research have later extended the concept to topics other than synesthesia and as it turned out applicable to everyday perception
the concept have developed into a theory of how we perceive. For
example ideasthesia has been applied to the theory of art and could bear
important implications in explaining human conscious experience, which, according to ideasthesia, is grounded in how we activate concepts.
Examples and evidence
A drawing by a synesthete which illustrates time unit-space synesthesia/ideasthesia.
The months in a year are organized into a circle surrounding the
synesthete's body, each month having a fixed location in space and a
unique color.
A common example of synesthesia is the association between graphemes and colors, usually referred to as grapheme-color synesthesia.
Here, letters of the alphabet are associated with vivid experiences of
color. Studies have indicated that the perceived color is
context-dependent and is determined by the extracted meaning of a
stimulus. For example, an ambiguous stimulus '5' that can be interpreted
either as 'S' or '5' will have the color associated with 'S' or with
'5', depending on the context in which it is presented. If presented
among numbers, it will be interpreted as '5' and will associate the
respective color. If presented among letters, it will be interpreted as
'S' and will associate the respective synesthetic color.
Evidence for grapheme-color synesthesia comes also from the
finding that colors can be flexibly associated to graphemes, as new
meanings become assigned to those graphemes. In one study synesthetes
were presented with Glagolitic
letters that they have never seen before, and the meaning was acquired
through a short writing exercise. The Glagolitic graphemes inherited the
colors of the corresponding Latin graphemes as soon as the Glagolitic
graphemes acquired the new meaning.
In another study, synesthetes were prompted to form novel
synesthetic associations to graphemes never seen before. Synesthetes
created those associations within minutes or seconds - which was time
too short to account for creation of new physical connections between
color representation and grapheme representation areas in the brain,
pointing again towards ideasthesia. Although the time course is
consistent with postsynaptic AMPA receptor upregulation and/or NMDA
receptor coactivation, which would imply that the realtime experience is
invoked at the synaptic level of analysis prior to establishment of
novel wiring per se, a very intuitively appealing model.
For lexical-gustatory synesthesia
evidence also points towards ideasthesia: In lexical-gustatory
synesthesia, verbalisation of the stimulus is not necessary for the
experience of concurrents. Instead, it is sufficient to activate the
concept.
Another case of synesthesia is swimming-style synesthesia in
which each swimming style is associated with a vivid experience of a
color.
These synesthetes do not need to perform the actual movements of a
corresponding swimming style. To activate the concurrent experiences, it
is sufficient to activate the concept of a swimming style (e.g., by
presenting a photograph of a swimmer or simply talking about swimming).
It has been argued that grapheme-color synesthesia for geminate consonants also provides evidence for ideasthesia.
In pitch-color synesthesia, the same tone will be associated with
different colors depending on how it has been named; do-sharp (i.e. di)
will have colors similar to do (e.g., a reddish color) and re-flat
(i.e. ra) will have color similar to that of re (e.g., yellowish),
although the two classes refer to the same tone. Similar semantic associations have been found between the acoustic characteristics of vowels and the notion of size.
One-shot synesthesia: There are synesthetic experiences
that can occur just once in a lifetime, and are thus dubbed one-shot
synesthesia. Investigation of such cases has indicated that such unique
experiences typically occur when a synesthete is involved in an
intensive mental and emotional activity such as making important plans
for one's future or reflecting on one's life. It has been thus concluded
that this is also a form of ideasthesia.
In normal perception
Which
one would be called Bouba and which Kiki? Responses are highly
consistent among people. This is an example of ideasthesia as the
conceptualization of the stimulus plays an important role.
Over the past decade, it has been suggested that the Bouba/Kiki phenomenon is a case of ideasthesia. Most people will agree that the star-shaped object on the left is named Kiki and the round one on the right Bouba. It has been assumed that these associations come from direct connections between visual and auditory cortices.
For example, according to that hypothesis, representations of sharp
inflections in the star-shaped object would be physically connected to
the representations of sharp inflection in the sound of Kiki. However,
Gomez et al.
have shown that Kiki/Bouba associations are much richer as either word
and either image is associated semantically to a number of concepts such
as white or black color, feminine vs. masculine, cold vs. hot, and
others. These sound-shape associations seem to be related through a
large overlap between semantic networks
of Kiki and star-shape on one hand, and Bouba and round-shape on the
other hand. For example, both Kiki and star-shape are clever, small,
thin and nervous. This indicates that behind Kiki-Bouba effect lies a
rich semantic network. In other words, our sensory experience is largely
determined by the meaning that we assign to stimuli. Food description
and wine tasting is another domain in which ideasthetic association
between flavor and other modalities such as shape may play an important
role.
These semantic-like relations play a role in successful marketing; the
name of a product should match its other characteristics.
Implications for development of synesthesia
The concept of ideasthesia bears implications for understanding how synesthesia develops
in children. Synesthetic children may associate concrete sensory-like
experiences primarily to the abstract concepts that they have otherwise
difficulties dealing with.
Synesthesia may thus be used as a cognitive tool to cope with the
abstractness of the learning materials imposed by the educational system
— referred to also as a "semantic vacuum hypothesis". This hypothesis
explains why the most common inducers in synesthesia are graphemes and
time units — both relating to the first truly abstract ideas that a
child needs to master.
Implications for art theory
The concept of ideasthesia has been often discussed in relation to art, and also used to formulate a psychological theory of art.
According to the theory, we consider something to be a piece of art
when experiences induced by the piece are accurately balanced with
semantics induced by the same piece. Thus, a piece of art makes us both
strongly think and strongly experience. Moreover, the two must be
perfectly balanced such that the most salient stimulus or event is both
the one that evokes strongest experiences (fear, joy, ... ) and
strongest cognition (recall, memory, ...) — in other words, idea is well balanced with aesthesia.
Ideasthesia theory of art may be used for psychological studies of aesthetics. It may also help explain classificatory disputes about art
as its main tenet is that experience of art can only be individual,
depending on person's unique knowledge, experiences and history. There could exist no general classification of art satisfactorily applicable to each and all individuals.
Neurophysiology of ideasthesia
Ideasthesia is congruent with the theory of brain functioning known as practopoiesis.
According to that theory, concepts are not an emergent property of
highly developed, specialized neuronal networks in the brain, as is
usually assumed; rather, concepts are proposed to be fundamental to the
very adaptive principles by which living systems and the brain operate.
A study using magnetoencephalography
has shown that the information on synesthetic colors is available in
the brain signals only about 200 milliseconds after the stimulus, which
is consistent with conceptual mediation. The study supports the idea that synesthesia is a semantic phenomenon—i.e., ideasthesia.
In philosophy of mind and consciousness, the explanatory gap is the difficulty that physicalist
theories have in explaining how physical properties give rise to the
way things feel when they are experienced. It is a term introduced by
philosopher Joseph Levine. In the 1983 paper in which he first used the term, he used as an example the sentence, "Pain is the firing of C fibers", pointing out that while it might be valid in a physiological sense, it does not help us to understand how pain feels.
The explanatory gap has vexed and intrigued philosophers and AI
researchers alike for decades and caused considerable debate. Bridging
this gap (that is, finding a satisfying mechanistic explanation for
experience and qualia) is known as "the hard problem".
To take an example of a phenomenon in which there is no gap, a
modern computer's behavior can be adequately explained by its physical
components alone, such as its circuitry and software.In contrast, it is thought by many mind-body dualists (e.g. René Descartes, David Chalmers) that subjective conscious experience
constitutes a separate effect that demands another cause that is either
outside the physical world (dualism) or due to an as yet unknown
physical phenomenon (see for instance quantum mind, indirect realism).
Proponents of dualism claim that the mind is substantially and qualitatively different from the brain and that the existence of something metaphysically extra-physical is required to "fill the gap". Similarly, some argue that there are further facts—facts
that do not follow logically from the physical facts of the world—about
conscious experience. For example, they argue that what it is like to experience seeing red does not follow logically from the physical facts of the world.
Implications
The
nature of the explanatory gap has been the subject of some debate. For
example, some consider it to simply be a limit on our current
explanatory ability.
They argue that future findings in neuroscience or future work from
philosophers could close the gap. However, others have taken a stronger
position and argued that the gap is a definite limit on our cognitive
abilities as humans—no amount of further information will allow us to
close it.
There has also been no consensus regarding what metaphysical
conclusions the existence of the gap provides. Those wishing to use its
existence to support dualism have often taken the position that an
epistemic gap—particularly if it is a definite limit on our cognitive
abilities—necessarily entails a metaphysical gap.
Levine and others have wished to either remain silent on the
matter or argue that no such metaphysical conclusion should be drawn. He agrees that conceivability (as used in the Zombie and inverted spectrum arguments) is flawed as a means of establishing metaphysical realities; but he points out that even if we come to the metaphysical conclusion that qualia are physical, they still present an explanatory problem.
While I think this materialist response is right in the
end, it does not suffice to put the mind-body problem to rest. Even if
conceivability considerations do not establish that the mind is in fact
distinct from the body, or that mental properties are metaphysically
irreducible to physical properties, still they do demonstrate that we
lack an explanation of the mental in terms of the physical.
However, such an epistemological
or explanatory problem might indicate an underlying metaphysical
issue—the non-physicality of qualia, even if not proven by
conceivability arguments is far from ruled out.
In the end, we are right back where we started. The
explanatory gap argument doesn't demonstrate a gap in nature, but a gap
in our understanding of nature. Of course a plausible explanation for
there being a gap in our understanding of nature is that there is a
genuine gap in nature. But so long as we have countervailing reasons for
doubting the latter, we have to look elsewhere for an explanation of
the former.
At the core of the problem, according to Levine, is our lack of
understanding of what it means for a qualitative experience to be fully
comprehended. He emphasizes that we don't even know to what extent it is
appropriate to inquire into the nature of this kind of experience. He
uses the laws of gravity as an example, which laws seem to explain
gravity completely yet do not account for the gravitational constant.
Similarly to the way in which gravity appears to be an inexplicable
brute fact of nature, the case of qualia may be one in which we are
either lacking essential information or in which we're exploring a
natural phenomenon that simply is not further apprehensible. Levine
suggests that, as qualitative experience of a physical or functional
state may simply be such a brute fact, perhaps we should consider
whether or not it is really necessary to find a more complete
explanation of qualitative experience.
Levine points out that the solution to the problem of
understanding how much there is to be known about qualitative experience
seems even more difficult because we also lack a way to articulate what
it means for actualities to be knowable in the manner that he has in
mind. He does conclude that there are good reasons why we wish for a
more complete explanation of qualitative experiences. One very
significant reason is that consciousness appears to only manifest where
mentality is demonstrated in physical systems that are quite highly
organized. This, of course, may be indicative of a human capacity for
reasoning that is no more than the result of organized functions. Levine
expresses that it seems counterintuitive to accept this implication
that the human brain, so highly organized as it is, could be no more
than a routine executor. He notes that although, at minimum, Materialism
appears to entail reducibility of anything that is not physically
primary to an explanation of its dependence on a mechanism that can be
described in terms of physical fundamentals, that kind of reductionism
doesn't attempt to reduce psychology to physical science. However, it
still entails that there are inexplicable classes of facts which are not
treated as relevant to statements pertinent to psychology.
The Chinese room argument holds that a digital computer executing a program cannot be shown to have a "mind", "understanding" or "consciousness",
regardless of how intelligently or human-like the program may make the
computer behave. The argument was first presented by philosopher John Searle in his paper, "Minds, Brains, and Programs", published in Behavioral and Brain Sciences in 1980. It has been widely discussed in the years since. The centerpiece of the argument is a thought experiment known as the Chinese room.
The argument is directed against the philosophical positions of functionalism and computationalism,
which hold that the mind may be viewed as an information-processing
system operating on formal symbols, and that simulation of a given
mental state is sufficient for its presence. Specifically, the argument
is intended to refute a position Searle calls strong AI: "The
appropriately programmed computer with the right inputs and outputs
would thereby have a mind in exactly the same sense human beings have
minds."
Although it was originally presented in reaction to the statements of artificial intelligence
(AI) researchers, it is not an argument against the goals of mainstream
AI research, because it does not show a limit in the amount of
"intelligent" behavior a machine can display. The argument applies only to digital computers running programs and does not apply to machines in general.
Chinese room thought experiment
John Searle in December 2005
Searle's thought experiment begins with this hypothetical premise: suppose that artificial intelligence research has succeeded in constructing a computer that behaves as if it understands Chinese. It takes Chinese characters as input and, by following the instructions of a computer program,
produces other Chinese characters, which it presents as output.
Suppose, says Searle, that this computer performs its task so
convincingly that it comfortably passes the Turing test:
it convinces a human Chinese speaker that the program is itself a live
Chinese speaker. To all of the questions that the person asks, it makes
appropriate responses, such that any Chinese speaker would be convinced
that they are talking to another Chinese-speaking human being.
The question Searle wants to answer is this: does the machine literally "understand" Chinese? Or is it merely simulating the ability to understand Chinese? Searle calls the first position "strong AI" and the latter "weak AI".
Searle then supposes that he is in a closed room and has a book
with an English version of the computer program, along with sufficient
papers, pencils, erasers, and filing cabinets. Searle could receive
Chinese characters through a slot in the door, process them according to
the program's instructions, and produce Chinese characters as output.
If the computer had passed the Turing test this way, it follows, says
Searle, that he would do so as well, simply by running the program
manually.
Searle asserts that there is no essential difference between the
roles of the computer and himself in the experiment. Each simply follows
a program, step-by-step, producing a behavior which is then interpreted
by the user as demonstrating intelligent conversation. However, Searle
himself would not be able to understand the conversation. ("I don't
speak a word of Chinese," he points out.) Therefore, he argues, it follows that the computer would not be able to understand the conversation either.
Searle argues that, without "understanding" (or "intentionality"),
we cannot describe what the machine is doing as "thinking" and, since
it does not think, it does not have a "mind" in anything like the normal
sense of the word. Therefore, he concludes that the "strong AI"
hypothesis is false.
History
Gottfried Leibniz made a similar argument in 1714 against mechanism
(the position that the mind is a machine and nothing more). Leibniz
used the thought experiment of expanding the brain until it was the size
of a mill.
Leibniz found it difficult to imagine that a "mind" capable of
"perception" could be constructed using only mechanical processes. In the 1961 short story "The Game" by Anatoly Dneprov,
a stadium of people act as switches and memory cells implementing a
program to translate a sentence of Portuguese, a language that none of
them knows. In 1974, Lawrence Davis imagined duplicating the brain using telephone lines and offices staffed by people, and in 1978 Ned Block envisioned the entire population of China involved in such a brain simulation. This thought experiment is called the China brain, also the "Chinese Nation" or the "Chinese Gym".
The Chinese Room Argument was introduced in Searle's 1980 paper "Minds, Brains, and Programs", published in Behavioral and Brain Sciences. It eventually became the journal's "most influential target article",
generating an enormous number of commentaries and responses in the
ensuing decades, and Searle has continued to defend and refine the
argument in many papers, popular articles and books. David Cole writes
that "the Chinese Room argument has probably been the most widely
discussed philosophical argument in cognitive science to appear in the
past 25 years".
Most of the discussion consists of attempts to refute it. "The overwhelming majority", notes BBS editor Stevan Harnad, "still think that the Chinese Room Argument is dead wrong". The sheer volume of the literature that has grown up around it inspired Pat Hayes to comment that the field of cognitive science ought to be redefined as "the ongoing research program of showing Searle's Chinese Room Argument to be false".
Searle's argument has become "something of a classic in cognitive science", according to Harnad. Varol Akman agrees, and has described the original paper as "an exemplar of philosophical clarity and purity".
The appropriately programmed computer with the right inputs and
outputs would thereby have a mind in exactly the same sense human beings
have minds.
The definition depends on the distinction between simulating a mind and actually having
a mind. Searle writes that "according to Strong AI, the correct
simulation really is a mind. According to Weak AI, the correct
simulation is a model of the mind."
The claim is implicit in some of the statements of early AI researchers and analysts. For example, in 1955, AI founder Herbert A. Simon declared that "there are now in the world machines that think, that learn and create". Simon, together with Allen Newell and Cliff Shaw, after having completed the first "AI" program, the Logic Theorist, claimed that they had "solved the venerable mind–body problem, explaining how a system composed of matter can have the properties of mind." John Haugeland wrote that "AI wants only the genuine article: machines with minds,
in the full and literal sense. This is not science fiction, but real
science, based on a theoretical conception as deep as it is daring:
namely, we are, at root, computers ourselves."
Searle also ascribes the following claims to advocates of strong AI:
AI systems can be used to explain the mind;
The study of the brain is irrelevant to the study of the mind; and
The Turing test is adequate for establishing the existence of mental states.
Strong AI as computationalism or functionalism
In more recent presentations of the Chinese room argument, Searle has identified "strong AI" as "computer functionalism" (a term he attributes to Daniel Dennett). Functionalism is a position in modern philosophy of mind
that holds that we can define mental phenomena (such as beliefs,
desires, and perceptions) by describing their functions in relation to
each other and to the outside world. Because a computer program can
accurately represent functional relationships as relationships between
symbols, a computer can have mental phenomena if it runs the right
program, according to functionalism.
Stevan Harnad argues that Searle's depictions of strong AI can be reformulated as "recognizable tenets of computationalism, a position (unlike "strong AI") that is actually held by many thinkers, and hence one worth refuting." Computationalism is the position in the philosophy of mind which argues that the mind can be accurately described as an information-processing system.
Each of the following, according to Harnad, is a "tenet" of computationalism:
Mental states are computational states (which is why computers can have mental states and help to explain the mind);
Computational states are implementation-independent—in
other words, it is the software that determines the computational
state, not the hardware (which is why the brain, being hardware, is
irrelevant); and that
Since implementation is unimportant, the only empirical data that matters is how the system functions; hence the Turing test is definitive.
Strong AI vs. biological naturalism
Searle holds a philosophical position he calls "biological naturalism": that consciousness and understanding require specific biological machinery that are found in brains. He writes "brains cause minds" and that "actual human mental phenomena [are] dependent on actual physical–chemical properties of actual human brains". Searle argues that this machinery (known to neuroscience as the "neural correlates of consciousness") must have some causal powers that permit the human experience of consciousness. Searle's belief in the existence of these powers has been criticized.
Searle does not disagree with the notion that machines can have
consciousness and understanding, because, as he writes, "we are
precisely such machines".
Searle holds that the brain is, in fact, a machine, but that the brain
gives rise to consciousness and understanding using machinery that is
non-computational. If neuroscience is able to isolate the mechanical
process that gives rise to consciousness, then Searle grants that it may
be possible to create machines that have consciousness and
understanding. However, without the specific machinery required, Searle
does not believe that consciousness can occur.
Biological naturalism implies that one cannot determine if the
experience of consciousness is occurring merely by examining how a
system functions, because the specific machinery of the brain is
essential. Thus, biological naturalism is directly opposed to both behaviorism and functionalism (including "computer functionalism" or "strong AI"). Biological naturalism is similar to identity theory
(the position that mental states are "identical to" or "composed of"
neurological events); however, Searle has specific technical objections
to identity theory. Searle's biological naturalism and strong AI are both opposed to Cartesian dualism,
the classical idea that the brain and mind are made of different
"substances". Indeed, Searle accuses strong AI of dualism, writing that
"strong AI only makes sense given the dualistic assumption that, where
the mind is concerned, the brain doesn't matter."
Consciousness
Searle's original presentation emphasized "understanding"—that is, mental states with what philosophers call "intentionality"—and
did not directly address other closely related ideas such as
"consciousness". However, in more recent presentations Searle has
included consciousness as the real target of the argument.
Computational models of
consciousness are not sufficient by themselves for consciousness. The
computational model for consciousness stands to consciousness in the
same way the computational model of anything stands to the domain being
modelled. Nobody supposes that the computational model of rainstorms in
London will leave us all wet. But they make the mistake of supposing
that the computational model of consciousness is somehow conscious. It
is the same mistake in both cases.
— John R. Searle, Consciousness and Language, p. 16
David Chalmers writes "it is fairly clear that consciousness is at the root of the matter" of the Chinese room.
Colin McGinn argues that the Chinese room provides strong evidence that the hard problem of consciousness
is fundamentally insoluble. The argument, to be clear, is not about
whether a machine can be conscious, but about whether it (or anything
else for that matter) can be shown to be conscious. It is plain that any
other method of probing the occupant of a Chinese room has the same
difficulties in principle as exchanging questions and answers in
Chinese. It is simply not possible to divine whether a conscious agency
or some clever simulation inhabits the room.
Searle argues that this is only true for an observer outside of the room. The whole point of the thought experiment is to put someone inside
the room, where they can directly observe the operations of
consciousness. Searle claims that from his vantage point within the room
there is nothing he can see that could imaginably give rise to
consciousness, other than himself, and clearly he does not have a mind
that can speak Chinese.
Applied ethics
Sitting in the combat information center aboard a warship – proposed as a real-life analog to the Chinese Room
Patrick Hew used the Chinese Room argument to deduce requirements from military command and control systems if they are to preserve a commander's moral agency. He drew an analogy between a commander in their command center and the person in the Chinese Room, and analyzed it under a reading of Aristotle’s notions of "compulsory" and "ignorance".
Information could be "down converted" from meaning to symbols, and
manipulated symbolically, but moral agency could be undermined if there
was inadequate 'up conversion' into meaning. Hew cited examples from the
USS Vincennes incident.
Computer science
The Chinese room argument is primarily an argument in the philosophy of mind, and both major computer scientists and artificial intelligence researchers consider it irrelevant to their fields. However, several concepts developed by computer scientists are essential to understanding the argument, including symbol processing, Turing machines, Turing completeness, and the Turing test.
Strong AI vs. AI research
Searle's arguments are not usually considered an issue for AI research. Stuart Russell and Peter Norvig
observe that most AI researchers "don't care about the strong AI
hypothesis—as long as the program works, they don't care whether you
call it a simulation of intelligence or real intelligence." The primary mission of artificial intelligence research is only to create useful systems that act intelligently, and it does not matter if the intelligence is "merely" a simulation.
Searle does not disagree that AI research can create machines
that are capable of highly intelligent behavior. The Chinese room
argument leaves open the possibility that a digital machine could be
built that acts more intelligently than a person, but does not have a mind or intentionality in the same way that brains do.
Searle's "strong AI" should not be confused with "strong AI" as defined by Ray Kurzweil and other futurists,
who use the term to describe machine intelligence that rivals or
exceeds human intelligence. Kurzweil is concerned primarily with the amount of intelligence displayed by the machine, whereas Searle's argument sets no limit on this. Searle argues that even a superintelligent machine would not necessarily have a mind and consciousness.
Turing test
The
"standard interpretation" of the Turing Test, in which player C, the
interrogator, is given the task of trying to determine which player – A
or B – is a computer and which is a human. The interrogator is limited
to using the responses to written questions to make the determination.
Image adapted from Saygin, et al. 2000.
The Chinese room implements a version of the Turing test. Alan Turing
introduced the test in 1950 to help answer the question "can machines
think?" In the standard version, a human judge engages in a natural
language conversation with a human and a machine designed to generate
performance indistinguishable from that of a human being. All
participants are separated from one another. If the judge cannot
reliably tell the machine from the human, the machine is said to have
passed the test.
Turing then considered each possible objection to the proposal
"machines can think", and found that there are simple, obvious answers
if the question is de-mystified in this way. He did not, however, intend
for the test to measure for the presence of "consciousness" or
"understanding". He did not believe this was relevant to the issues that
he was addressing. He wrote:
I do not wish to give the
impression that I think there is no mystery about consciousness. There
is, for instance, something of a paradox connected with any attempt to
localise it. But I do not think these mysteries necessarily need to be
solved before we can answer the question with which we are concerned in
this paper.
To Searle, as a philosopher investigating in the nature of mind and consciousness,
these are the relevant mysteries. The Chinese room is designed to show
that the Turing test is insufficient to detect the presence of
consciousness, even if the room can behave or function as a conscious mind would.
Searle emphasizes the fact that this kind of symbol manipulation is syntactic (borrowing a term from the study of grammar). The computer manipulates the symbols using a form of syntax rules, without any knowledge of the symbol's semantics (that is, their meaning).
Newell and Simon had conjectured that a physical symbol system
(such as a digital computer) had all the necessary machinery for
"general intelligent action", or, as it is known today, artificial general intelligence. They framed this as a philosophical position, the physical symbol system hypothesis: "A physical symbol system has the necessary and sufficient means for general intelligent action." The Chinese room argument does not refute this, because it is framed in
terms of "intelligent action", i.e. the external behavior of the
machine, rather than the presence or absence of understanding,
consciousness and mind.
Chinese room and Turing completeness
The Chinese room has a design analogous to that of a modern computer. It has a Von Neumann architecture, which consists of a program (the book of instructions), some memory (the papers and file cabinets), a CPU
which follows the instructions (the man), and a means to write symbols
in memory (the pencil and eraser). A machine with this design is known
in theoretical computer science as "Turing complete", because it has the necessary machinery to carry out any computation that a Turing machine
can do, and therefore it is capable of doing a step-by-step simulation
of any other digital machine, given enough memory and time. Alan Turing writes, "all digital computers are in a sense equivalent." The widely accepted Church–Turing thesis holds that any function computable by an effective procedure is computable by a Turing machine.
The Turing completeness of the Chinese room implies that it can
do whatever any other digital computer can do (albeit much, much more
slowly). Thus, if the Chinese room does not or can not contain a
Chinese-speaking mind, then no other digital computer can contain a
mind. Some replies to Searle begin by arguing that the room, as
described, cannot have a Chinese-speaking mind. Arguments of this form,
according to Stevan Harnad, are "no refutation (but rather an affirmation)" of the Chinese room argument, because these arguments actually imply that no digital computers can have a mind.
There are some critics, such as Hanoch Ben-Yami, who argue that
the Chinese room cannot simulate all the abilities of a digital
computer, such as being able to determine the current time.
Complete argument
Searle
has produced a more formal version of the argument of which the Chinese
Room forms a part. He presented the first version in 1984. The version
given below is from 1990.
The only part of the argument which should be controversial is A3 and
it is this point which the Chinese room thought experiment is intended
to prove.
A program uses syntax to manipulate symbols and pays no attention to the semantics
of the symbols. It knows where to put the symbols and how to move them
around, but it doesn't know what they stand for or what they mean. For
the program, the symbols are just physical objects like any others.
Unlike the symbols used by a program, our thoughts have meaning: they represent things and we know what it is they represent.
(A3) "Syntax by itself is neither constitutive of nor sufficient for semantics."
This is what the Chinese room thought experiment is intended to
prove: the Chinese room has syntax (because there is a man in there
moving symbols around). The Chinese room has no semantics (because,
according to Searle, there is no one or nothing in the room that
understands what the symbols mean). Therefore, having syntax is not
enough to generate semantics.
Searle posits that these lead directly to this conclusion:
(C1) Programs are neither constitutive of nor sufficient for minds.
This should follow without controversy from the first three:
Programs don't have semantics. Programs have only syntax, and syntax is
insufficient for semantics. Every mind has semantics. Therefore no
programs are minds.
This much of the argument is intended to show that artificial intelligence
can never produce a machine with a mind by writing programs that
manipulate symbols. The remainder of the argument addresses a different
issue. Is the human brain running a program? In other words, is the computational theory of mind correct? He begins with an axiom that is intended to express the basic modern scientific consensus about brains and minds:
(A4) Brains cause minds.
Searle claims that we can derive "immediately" and "trivially" that:
(C2) Any other system capable of causing minds would have to have causal powers (at least) equivalent to those of brains.
Brains must have something that causes a mind to exist. Science
has yet to determine exactly what it is, but it must exist, because
minds exist. Searle calls it "causal powers". "Causal powers" is
whatever the brain uses to create a mind. If anything else can cause a
mind to exist, it must have "equivalent causal powers". "Equivalent
causal powers" is whatever else that could be used to make a mind.
And from this he derives the further conclusions:
(C3) Any artifact that produced mental phenomena, any artificial
brain, would have to be able to duplicate the specific causal powers of
brains, and it could not do that just by running a formal program.
This follows from
C1 and C2: Since no program can produce a mind, and "equivalent causal
powers" produce minds, it follows that programs do not have "equivalent
causal powers."
(C4) The way that human brains actually produce mental phenomena cannot be solely by virtue of running a computer program.
Since programs do not have "equivalent causal powers",
"equivalent causal powers" produce minds, and brains produce minds, it
follows that brains do not use programs to produce minds.
Replies
Replies to Searle's argument may be classified according to what they claim to show:
Those which identify who speaks Chinese
Those which demonstrate how meaningless symbols can become meaningful
Those which suggest that the Chinese room should be redesigned in some way
Those which contend that Searle's argument is misleading
Those which argue that the argument makes false assumptions about subjective conscious experience and therefore proves nothing
Some of the arguments (robot and brain simulation, for example) fall into multiple categories.
Systems and virtual mind replies: finding the mind
These replies attempt to answer the question: since the man in the room doesn't speak Chinese, where is the "mind" that does? These replies address the key ontological issues of mind vs. body and simulation vs. reality. All of the replies that identify the mind in the room are versions of "the system reply".
System reply
The basic version argues that it is the "whole system" that understands Chinese.
While the man understands only English, when he is combined with the
program, scratch paper, pencils and file cabinets, they form a system
that can understand Chinese. "Here, understanding is not being ascribed
to the mere individual; rather it is being ascribed to this whole system
of which he is a part" Searle explains. The fact that man does not understand Chinese is irrelevant, because it is only the system as a whole that matters.
Searle notes that (in this simple version of the reply) the "system"
is nothing more than a collection of ordinary physical objects; it
grants the power of understanding and consciousness to "the conjunction
of that person and bits of paper"
without making any effort to explain how this pile of objects has
become a conscious, thinking being. Searle argues that no reasonable
person should be satisfied with the reply, unless they are "under the
grip of an ideology;"
In order for this reply to be remotely plausible, one must take it for
granted that consciousness can be the product of an information
processing "system", and does not require anything resembling the actual
biology of the brain.
Searle then responds by simplifying this list of physical
objects: he asks what happens if the man memorizes the rules and keeps
track of everything in his head? Then the whole system consists of just
one object: the man himself. Searle argues that if the man doesn't
understand Chinese then the system doesn't understand Chinese either
because now "the system" and "the man" both describe exactly the same
object.
Critics of Searle's response argue that the program has allowed the man to have two minds in one head. If we assume a "mind" is a form of information processing, then the theory of computation can account for two computations occurring at once, namely (1) the computation for universal programmability (which is the function instantiated by the person and note-taking materials independently
from any particular program contents) and (2) the computation of the
Turing machine that is described by the program (which is instantiated
by everything including the specific program).
The theory of computation thus formally explains the open possibility
that the second computation in the Chinese Room could entail a
human-equivalent semantic understanding of the Chinese inputs. The focus
belongs on the program's Turing machine rather than on the person's.
However, from Searle's perspective, this argument is circular. The
question at issue is whether consciousness is a form of information
processing, and this reply requires that we make that assumption.
More sophisticated versions of the systems reply try to identify
more precisely what "the system" is and they differ in exactly how they
describe it. According to these replies,
the "mind that speaks Chinese" could be such things as: the "software",
a "program", a "running program", a simulation of the "neural
correlates of consciousness", the "functional system", a "simulated
mind", an "emergent property", or "a virtual mind" (Marvin Minsky's version of the systems reply, described below).
Virtual mind reply
The term "virtual"
is used in computer science to describe an object that appears to exist
"in" a computer (or computer network) only because software makes it
appear to exist. The objects "inside" computers (including files,
folders, and so on) are all "virtual", except for the computer's
electronic components. Similarly, Minsky argues, a computer may contain a "mind" that is virtual in the same sense as virtual machines, virtual communities and virtual reality.
To clarify the distinction between the simple systems reply
given above and virtual mind reply, David Cole notes that two
simulations could be running on one system at the same time: one
speaking Chinese and one speaking Korean. While there is only one
system, there can be multiple "virtual minds," thus the "system" cannot
be the "mind".
Searle responds that such a mind is, at best, a simulation,
and writes: "No one supposes that computer simulations of a five-alarm
fire will burn the neighborhood down or that a computer simulation of a
rainstorm will leave us all drenched."
Nicholas Fearn responds that, for some things, simulation is as good as
the real thing. "When we call up the pocket calculator function on a
desktop computer, the image of a pocket calculator appears on the
screen. We don't complain that 'it isn't really a calculator', because the physical attributes of the device do not matter."
The question is, is the human mind like the pocket calculator,
essentially composed of information? Or is the mind like the rainstorm,
something other than a computer, and not realizable in full by a
computer simulation? For decades, this question of simulation has lead
AI researchers and philosophers to consider whether the term "synthetic intelligence" is more appropriate than the common description of such intelligences as "artificial."
These replies provide an explanation of exactly who it is that understands Chinese. If there is something besides
the man in the room that can understand Chinese, Searle can't argue
that (1) the man doesn't understand Chinese, therefore (2) nothing in
the room understands Chinese. This, according to those who make this
reply, shows that Searle's argument fails to prove that "strong AI" is
false.
These replies, by themselves, do not provide any evidence that
strong AI exists or can exist, however. They do not show that the system
(or the virtual mind) understands Chinese, other than the hypothetical premise that it passes the Turing Test.
Searle argues that, if we are to consider Strong AI remotely plausible,
the Chinese Room is an example that requires explanation, and it is
difficult or impossible to explain how consciousness might "emerge" from
the room or how the system would have consciousness. As Searle writes
"the systems reply simply begs the question by insisting that the system
must understand Chinese" and thus is dodging the question or hopelessly circular.
Robot and semantics replies: finding the meaning
As
far as the person in the room is concerned, the symbols are just
meaningless "squiggles." But if the Chinese room really "understands"
what it is saying, then the symbols must get their meaning from
somewhere. These arguments attempt to connect the symbols to the things
they symbolize. These replies address Searle's concerns about intentionality, symbol grounding and syntax vs. semantics.
Robot reply
Suppose
that instead of a room, the program was placed into a robot that could
wander around and interact with its environment. This would allow a "causal connection" between the symbols and things they represent. Hans Moravec
comments: "If we could graft a robot to a reasoning program, we
wouldn't need a person to provide the meaning anymore: it would come
from the physical world."
Searle's reply is to suppose that, unbeknownst to the individual
in the Chinese room, some of the inputs came directly from a camera
mounted on a robot, and some of the outputs were used to manipulate the
arms and legs of the robot. Nevertheless, the person in the room is
still just following the rules, and does not know what the symbols mean. Searle writes "he doesn't see what comes into the robot's eyes."
Derived meaning
Some respond that the room, as Searle describes it, is connected to the world: through the Chinese speakers that it is "talking" to and through the programmers who designed the knowledge base in his file cabinet. The symbols Searle manipulates are already meaningful, they're just not meaningful to him.
Searle says that the symbols only have a "derived" meaning, like
the meaning of words in books. The meaning of the symbols depends on
the conscious understanding of the Chinese speakers and the programmers
outside the room. The room, like a book, has no understanding of its
own.
Commonsense knowledge / contextualist reply
Some have argued that the meanings of the symbols would come from a vast "background" of commonsense knowledge encoded in the program and the filing cabinets. This would provide a "context" that would give the symbols their meaning.
Searle agrees that this background exists, but he does not agree that it can be built into programs. Hubert Dreyfus has also criticized the idea that the "background" can be represented symbolically.
To each of these suggestions, Searle's response is the same: no
matter how much knowledge is written into the program and no matter how
the program is connected to the world, he is still in the room
manipulating symbols according to rules. His actions are syntactic and this can never explain to him what the symbols stand for. Searle writes "syntax is insufficient for semantics."
However, for those who accept that Searle's actions simulate a
mind, separate from his own, the important question is not what the
symbols mean to Searle, what is important is what they mean to the virtual mind.
While Searle is trapped in the room, the virtual mind is not: it is
connected to the outside world through the Chinese speakers it speaks
to, through the programmers who gave it world knowledge, and through the
cameras and other sensors that roboticists can supply.
Brain simulation and connectionist replies: redesigning the room
These arguments are all versions of the systems reply that identify a particular kind
of system as being important; they identify some special technology
that would create conscious understanding in a machine. (The "robot" and
"commonsense knowledge" replies above also specify a certain kind of
system as being important.)
Brain simulator reply
Suppose that the program simulated in fine detail the action of every neuron in the brain of a Chinese speaker.
This strengthens the intuition that there would be no significant
difference between the operation of the program and the operation of a
live human brain.
Searle replies that such a simulation does not reproduce the important features of the brain—its causal and intentional states. Searle is adamant that "human mental phenomena [are] dependent on actual physical–chemical properties of actual human brains." Moreover, he argues:
[I]magine that instead of a
monolingual man in a room shuffling symbols we have the man operate an
elaborate set of water pipes with valves connecting them. When the man
receives the Chinese symbols, he looks up in the program, written in
English, which valves he has to turn on and off. Each water connection
corresponds to a synapse in the Chinese brain, and the whole system is
rigged up so that after doing all the right firings, that is after
turning on all the right faucets, the Chinese answers pop out at the
output end of the series of pipes.
Now where is the understanding in this system? It takes Chinese as
input, it simulates the formal structure of the synapses of the Chinese
brain, and it gives Chinese as output. But the man certainly doesn't
understand Chinese, and neither do the water pipes, and if we are
tempted to adopt what I think is the absurd view that somehow the
conjunction of man and water pipes understands, remember that in
principle the man can internalize the formal structure of the water
pipes and do all the "neuron firings" in his imagination.
Two variations on the brain simulator reply are the China brain and the brain-replacement scenario.
China brain
What if we ask each citizen of China to simulate one neuron, using the telephone system to simulate the connections between axons and dendrites? In this version, it seems obvious that no individual would have any understanding of what the brain might be saying.
It is also obvious that this system would be functionally equivalent to
a brain, so if consciousness is a function, this system would be
conscious.
Brain replacement scenario
In
this, we are asked to imagine that engineers have invented a tiny
computer that simulates the action of an individual neuron. What would
happen if we replaced one neuron at a time? Replacing one would clearly
do nothing to change conscious awareness. Replacing all of them would
create a digital computer that simulates a brain. If Searle is right,
then conscious awareness must disappear during the procedure (either
gradually or all at once). Searle's critics argue that there would be no
point during the procedure when he can claim that conscious awareness
ends and mindless simulation begins.
Searle predicts that, while going through the brain prosthesis, "you
find, to your total amazement, that you are indeed losing control of
your external behavior. You find, for example, that when doctors test
your vision, you hear them say 'We are holding up a red object in front
of you; please tell us what you see.' You want to cry out 'I can't see
anything. I'm going totally blind.' But you hear your voice saying in a
way that is completely outside of your control, 'I see a red object in
front of me.' [...] [Y]our conscious experience slowly shrinks to
nothing, while your externally observable behavior remains the same."
Connectionist replies
Closely
related to the brain simulator reply, this claims that a massively
parallel connectionist architecture would be capable of understanding.
Combination reply
This
response combines the robot reply with the brain simulation reply,
arguing that a brain simulation connected to the world through a robot
body could have a mind.
Many mansions / wait till next year reply
Better technology in the future will allow computers to understand.
Searle agrees that this is possible, but considers this point
irrelevant. Searle agrees that there may be designs that would cause a
machine to have conscious understanding.
These arguments (and the robot or commonsense knowledge replies)
identify some special technology that would help create conscious
understanding in a machine. They may be interpreted in two ways: either
they claim (1) this technology is required for consciousness, the
Chinese room does not or cannot implement this technology, and therefore
the Chinese room cannot pass the Turing test or (even if it did) it
would not have conscious understanding. Or they may be claiming that (2)
it is easier to see that the Chinese room has a mind if we visualize
this technology as being used to create it.
In the first case, where features like a robot body or a
connectionist architecture are required, Searle claims that strong AI
(as he understands it) has been abandoned.
The Chinese room has all the elements of a Turing complete machine, and
thus is capable of simulating any digital computation whatsoever. If
Searle's room can't pass the Turing test then there is no other digital
technology that could pass the Turing test. If Searle's room could
pass the Turing test, but still does not have a mind, then the Turing
test is not sufficient to determine if the room has a "mind". Either
way, it denies one or the other of the positions Searle thinks of as
"strong AI", proving his argument.
The brain arguments in particular deny strong AI if they assume
that there is no simpler way to describe the mind than to create a
program that is just as mysterious as the brain was. He writes "I
thought the whole idea of strong AI was that we don't need to know how
the brain works to know how the mind works." If computation does not provide an explanation of the human mind, then strong AI has failed, according to Searle.
Other critics hold that the room as Searle described it does, in
fact, have a mind, however they argue that it is difficult to
see—Searle's description is correct, but misleading. By
redesigning the room more realistically they hope to make this more
obvious. In this case, these arguments are being used as appeals to
intuition (see next section).
In fact, the room can just as easily be redesigned to weaken our intuitions. Ned Block's Blockhead argument suggests that the program could, in theory, be rewritten into a simple lookup table of rules of the form "if the user writes S, reply with P and goto X". At least in principle, any program can be rewritten (or "refactored") into this form, even a brain simulation. In the blockhead scenario, the entire mental state is hidden in the letter X, which represents a memory address—a
number associated with the next rule. It is hard to visualize that an
instant of one's conscious experience can be captured in a single large
number, yet this is exactly what "strong AI" claims. On the other hand,
such a lookup table would be ridiculously large (to the point of being
physically impossible), and the states could therefore be extremely specific.
Searle argues that however the program is written or however the machine is connected to the world, the mind is being simulated
by a simple step-by-step digital machine (or machines). These machines
are always just like the man in the room: they understand nothing and
don't speak Chinese. They are merely manipulating symbols without
knowing what they mean. Searle writes: "I can have any formal program
you like, but I still understand nothing."
Speed and complexity: appeals to intuition
The
following arguments (and the intuitive interpretations of the arguments
above) do not directly explain how a Chinese speaking mind could exist
in Searle's room, or how the symbols he manipulates could become
meaningful. However, by raising doubts about Searle's intuitions they
support other positions, such as the system and robot replies. These
arguments, if accepted, prevent Searle from claiming that his conclusion
is obvious by undermining the intuitions that his certainty requires.
Several critics believe that Searle's argument relies entirely on intuitions. Ned Block writes "Searle's argument depends for its force on intuitions that certain entities do not think." Daniel Dennett describes the Chinese room argument as a misleading "intuition pump"
and writes "Searle's thought experiment depends, illicitly, on your
imagining too simple a case, an irrelevant case, and drawing the
'obvious' conclusion from it."
Some of the arguments above also function as appeals to
intuition, especially those that are intended to make it seem more
plausible that the Chinese room contains a mind, which can include the
robot, commonsense knowledge, brain simulation and connectionist
replies. Several of the replies above also address the specific issue of
complexity. The connectionist reply emphasizes that a working
artificial intelligence system would have to be as complex and as
interconnected as the human brain. The commonsense knowledge reply
emphasizes that any program that passed a Turing test would have to be
"an extraordinarily supple, sophisticated, and multilayered system,
brimming with 'world knowledge' and meta-knowledge and
meta-meta-knowledge", as Daniel Dennett explains.
Speed and complexity replies
The speed at which human brains process information is (by some estimates) 100 billion operations per second.
Several critics point out that the man in the room would probably take
millions of years to respond to a simple question, and would require
"filing cabinets" of astronomical proportions. This brings the clarity
of Searle's intuition into doubt.
An especially vivid version of the speed and complexity reply is from Paul and Patricia Churchland. They propose this analogous thought experiment:
Churchland's luminous room
"Consider
a dark room containing a man holding a bar magnet or charged object. If
the man pumps the magnet up and down, then, according to Maxwell's theory of artificial luminance (AL), it will initiate a spreading circle of electromagnetic
waves and will thus be luminous. But as all of us who have toyed with
magnets or charged balls well know, their forces (or any other forces
for that matter), even when set in motion produce no luminance at all.
It is inconceivable that you might constitute real luminance just by
moving forces around!"
The problem is that he would have to wave the magnet up and down
something like 450 trillion times per second in order to see anything.
Stevan Harnad
is critical of speed and complexity replies when they stray beyond
addressing our intuitions. He writes "Some have made a cult of speed and
timing, holding that, when accelerated to the right speed, the
computational may make a phase transition into the mental. It should be clear that is not a counterargument but merely an ad hoc speculation (as is the view that it is all just a matter of ratcheting up to the right degree of 'complexity.')"
Searle argues that his critics are also relying on intuitions,
however his opponents' intuitions have no empirical basis. He writes
that, in order to consider the "system reply" as remotely plausible, a
person must be "under the grip of an ideology".
The system reply only makes sense (to Searle) if one assumes that any
"system" can have consciousness, just by virtue of being a system with
the right behavior and functional parts. This assumption, he argues, is
not tenable given our experience of consciousness.
Other minds and zombies: meaninglessness
Several
replies argue that Searle's argument is irrelevant because his
assumptions about the mind and consciousness are faulty. Searle believes
that human beings directly experience their consciousness,
intentionality and the nature of the mind every day, and that this
experience of consciousness is not open to question. He writes that we
must "presuppose the reality and knowability of the mental."
These replies question whether Searle is justified in using his own
experience of consciousness to determine that it is more than mechanical
symbol processing. In particular, the other minds reply argues that we
cannot use our experience of consciousness to answer questions about
other minds (even the mind of a computer), and the epiphenomena reply
argues that Searle's consciousness does not "exist" in the sense that
Searle thinks it does.
Other minds reply
This reply points out that Searle's argument is a version of the problem of other minds,
applied to machines. There is no way we can determine if other people's
subjective experience is the same as our own. We can only study their
behavior (i.e., by giving them our own Turing test). Critics of Searle argue that he is holding the Chinese room to a higher standard than we would hold an ordinary person.
Nils Nilsson writes "If a program behaves as if it were multiplying, most of us would say that it is, in fact, multiplying. For all I know, Searle may only be behaving as if
he were thinking deeply about these matters. But, even though I
disagree with him, his simulation is pretty good, so I'm willing to
credit him with real thought."
Alan Turing
anticipated Searle's line of argument (which he called "The Argument
from Consciousness") in 1950 and makes the other minds reply.
He noted that people never consider the problem of other minds when
dealing with each other. He writes that "instead of arguing continually
over this point it is usual to have the polite convention that everyone
thinks." The Turing test
simply extends this "polite convention" to machines. He doesn't intend
to solve the problem of other minds (for machines or people) and he
doesn't think we need to.
Eliminative Materialism reply
Several philosophers argue that consciousness, as Searle describes
it, does not exist. This position is sometimes referred to as eliminative materialism:
the view that consciousness is a property that can be reduced to a
strictly mechanical description, and that our experience of
consciousness is, as Daniel Dennett describes it, a "user illusion". Other mental properties, such as original intentionality
(also called “meaning”, “content”, and “semantic character”), is also
commonly regarded as something special about beliefs and other
propositional attitudes. Eliminative materialism
maintains that propositional attitudes such as beliefs and desires,
among other intentional mental states that have content, do not exist.
If eliminative materialism
is the correct scientific account of human cognition then the
assumption of the Chinese room argument that "minds have mental contents
(semantics)" must be rejected.
Stuart Russell and Peter Norvig
argue that, if we accept Searle's description of intentionality,
consciousness and the mind, we are forced to accept that consciousness
is epiphenomenal:
that it "casts no shadow", that it is undetectable in the outside
world. They argue that Searle must be mistaken about the "knowability of
the mental", and in his belief that there are "causal properties" in
our neurons that give rise to the mind. They point out that, by Searle's
own description, these causal properties can't be detected by anyone
outside the mind, otherwise the Chinese Room couldn't pass the Turing test—the
people outside would be able to tell there wasn't a Chinese speaker in
the room by detecting their causal properties. Since they can't detect
causal properties, they can't detect the existence of the mental. In
short, Searle's "causal properties" and consciousness itself is
undetectable, and anything that cannot be detected either does not exist
or does not matter.
Daniel Dennett provides this extension to the "epiphenomena" argument.
Dennett's reply from natural selection
Suppose that, by some mutation, a human being is born that does not
have Searle's "causal properties" but nevertheless acts exactly like a
human being. (This sort of animal is called a "zombie" in thought experiments in the philosophy of mind).
This new animal would reproduce just as any other human and eventually
there would be more of these zombies. Natural selection would favor the
zombies, since their design is (we could suppose) a bit simpler.
Eventually the humans would die out. So therefore, if Searle is right,
it is most likely that human beings (as we see them today) are actually
"zombies", who nevertheless insist they are conscious. It is impossible
to know whether we are all zombies or not. Even if we are all zombies,
we would still believe that we are not.
Searle disagrees with this analysis and argues that "the study of the
mind starts with such facts as that humans have beliefs, while
thermostats, telephones, and adding machines don't ... what we wanted to
know is what distinguishes the mind from thermostats and livers." He takes it as obvious that we can detect the presence of consciousness and dismisses these replies as being off the point.
Mike Alder argues that the entire argument is frivolous, because it is non-verificationist: not only is the distinction between simulating a mind and having
a mind ill-defined, but it is also irrelevant because no experiments
were, or even can be, proposed to distinguish between the two.
English reply
Margaret Boden provided this reply in her paper "Escaping from the Chinese Room."
In it she suggests, that even if the person in the room does not
understand the Chinese, it does not mean there is no understanding in
the room. The person in the room at least understands the rule book used
to provide output responses.
In popular culture
The Chinese room argument is a central concept in Peter Watts's novels Blindsight and (to a lesser extent) Echopraxia. It is also a central theme in the video game Virtue's Last Reward, and ties into the game's narrative. In Season 4 of the American crime drama Numb3rs there is a brief reference to the Chinese room.
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