SUMMARY AND REVIEWS OF THE LITERATURE ON
CONSCIOUSNESS
JOHN SEARLE AND DAVID CHALMERS
reviewed By ANIL MITRA phd, 1999 updated May 2003
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Document status: May 21, 2003
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OUTLINE
John Searle, New York Review of Books, The Mystery of
Consciousness, 1997
John Searle, The Rediscovery of The Mind, 1992
David Chalmers, The Conscious Mind, 1996
CONTENTS
JOHN SEARLE,
NEW YORK REVIEW OF BOOKS, THE MYSTERY OF CONSCIOUSNESS, 1997
1 Consciousness
as a Biological Problem…with notes from the preface
2 Francis
Crick, the Binding Problem and the Hypothesis of Forty Hertz
3 Gerald
Edelman and Reentry Mapping
4 Roger
Penrose, Kurt Gödel, and the Cytoskeletons
5 Consciousness
Denied: Daniel Dennett’s Account
6 David
Chalmers and the Conscious Mind
7 Israel
Rosenfield, the Body Image, and the Self
8 Conclusion
How to Transform the Mystery of Consciousness into the Problem of consciousness
JOHN SEARLE,
THE REDISCOVERY OF THE MIND, 1992
1 What’s
Wrong with the Philosophy of Mind
2 The
Recent History of Materialism: The Same Mistake Over and Over
3 Breaking
the Hold: Silicon Grains, Conscious Robots, and Other Minds
4 Consciousness
and Its Place in Nature
5 Reductionism
and the Irreducibility of Consciousness
6 The
Structure of Consciousness: An Introduction
6.1 A
Dozen Structural Features
6.2 Three
Traditional Mistakes
7 The
Unconscious and Its Relation to Consciousness
8 Consciousness,
Intentionality, and the Background
9 The
Critique of Cognitive Reason
DAVID
CHALMERS, THE CONSCIOUS MIND, 1996
Introduction:
Taking Consciousness Seriously
1.2 The
phenomenal and psychological concepts of mind
1.3 The
double life of mental terms
1.4 The
two mind-body problems
1.5 Two
concepts of consciousness
2 Supervenience
and Explanation
2.3 Logical
supervenience and reductive explanation
2.4 Conceptual
truth and necessary truth*
2.5 Almost
everything is logically supervenient on the physics*
II. THE IRREDUCIBILITY OF
CONSCIOUSNESS
3 Can
Consciousness be reductively explained?
5 The
Paradox of Phenomenal Judgment
III. TOWARD A THEORY OF CONSCIOUSNESS
6 The
Coherence Between Consciousness and Cognition
7 Absent
Qualia, Fading Qualia, Dancing Qualia
8 Consciousness
and Information: Some Speculation
9 Strong
Artificial Intelligence
10 The
Interpretation of Quantum Mechanics
JOHN SEARLE,
Common sense definition of consciousness - as states of sentience and awareness - is simple…
Analytic definition [in terms of an underlying essence] and establishing consciousness-matter [brain] relations is hard
Problem 1: Cartesian Dualism seems to place consciousness
outside natural science
Eccles and others believe it is outside the explanations of science
The ideas “mental”, “physical”, “materialism”, “idealism”, “monism”, “dualism”…are thought of as clear and that the issues have to be posed and resolved in these traditional terms. This is a source of problems. As a result of accepting this framework the reality of consciousness implies dualism and negation of the scientific world view that took 400 years to develop. This motivates many scientists [Dennett is one] and philosophers to eliminate consciousness by reducing it to something else. A small number of scientists [Chalmers, Penrose and others] accept dualism - this, too, is problematical
Searle believes that the old categories and ingrained habits of thought need to be discarded. Consciousness is a biological problem: brain causes consciousness
Problem 2: That the brain “causes”
consciousness is “philosophically loaded” - it seems to imply dualism
But the implication is only on the “effect temporally follows cause” notion of causality
An example of cause-effect that is not temporal is the solidity of a table that is caused by the behavior of molecules but is not an extra event - it is a feature of the table
Consciousness is like that - it is a feature of the brain
Problem 3: How do publicly
observable phenomena - brain processes - produce the private, subjective
characteristic of all consciousness? This is the hard or philosophical
problem…I called it the fundamental problem
It is related to, but definitely not the same as the scientific problem of explaining, in detail the kinds and particulars of mental states and process on the basis of the kinds and particulars of the brains anatomical divisions and its physiological states and processes
Problem 4: Taking the computer metaphor of the mind too literally
Strong AI: mind is nothing but a computer program. Searle refutes this:
The Chinese room argument - minds have semantics; programs do not - they are purely syntactical. The Chinese room showed that semantics is not intrinsic to syntax. This argument due to Searle is famous; it dates to the early 1980s
Searle provides a newer argument, one that he thinks is more powerful and decisive: Syntax [computation] is not intrinsic to physics [computers] but is due to interpretation, i.e., it syntax is context dependent
Searle thinks that the breakthrough to explaining consciousness will come from some simple system. Still, says Searle, this does not detract from Crick’s neurobiological explanations of vision - a good choice since so much work has been done on it
Crick’s philosophical mistakes
Thinks the problem of qualia is about communicating the subjective aspect
Talks eliminative reduction, practices causal emergentism - the argument against elimination is that the two features exist despite reduction but Crick advances Patricia Churchland’s mistaken criticism of the anti-reductionist argument
Talks about the neural correlates of consciousness - which goes against reduction since a correlation is between two things - but correlation explains nothing - explanation requires a causal theory. Further, Crick sometimes denies direct perceptual awareness using a bad philosophical argument - the one that interpretations can sometimes be mistaken from the 17th century - due to Descartes and Hume
Crick talks of the binding problem - how the brain unifies the different aspects of a perception into a unified whole. Based on work by Wolf Singer in Frankfurt and others spatially separated neurons corresponding to shape, color, movement fire in the range of 40Hz Crick and Koch speculate that these might be the brain correlates of visual consciousness. Searle thinks this is not an explanation, it is at most an explanation and makes a proper analogy to an internal combustion engine, stating that combustion correlates with motion but this is not explanation
AM: an explanation would be that the chemical energy is really the sum of molecular potential energies that is liberated in combustion causing higher molecular kinetic energies and momentum that in turn cause greater forces to be exerted by individual molecules that aggregate as a greater total force exerted by the burning gas on a piston that causes motion. A black box macroscopic explanation could have been given but the microscopic aspect makes the analogy useful in the present context. There are two key points [1] the identification of micro-macro physical properties and [2] that at each point in the chain of events the causation is the invocation of a law - Newton’s second law of motion
Explanation of consciousness would be similar but an ingredient is missing: what is the identification of consciousness with the physical or biological levels that do not include explicit mention of consciousness[1]. The identification could be microscopic or macroscopic or both. However it poses a problem not present in the physical case for the identification of liberation of chemical energy with motion is based on a chain of reasoning through a law of physics. Where does the identification of consciousness with the physical level come in? It need not be through a law and three solution ideas arise; [1] just as force is causally related to motion through a causal law, what are the law-like causal powers of consciousness, [2] the flip from “as if” or third person to the phenomenal or first person modes of description could well be a simple identity once enough is known about bio-physiology and about consciousness and mind, and [3] identifying the material realm as a phase or territory within a graded idealism that includes the case of classical or other materialism and, possibly, natural rather than bridging laws. An alternative to idealism is to identify a realm of experience in a field that may be unspecified. The field may turn out to be matter, being, mind…and the relation to the field may be effect or correlate [matter], phase [being], embedding or identity [mind]. Lack of specification provides an overview within which specifications may be situated and related e.g. causal relationship is a case within correlation; there are various reasons for a disposition toward a causal relation but the final explanation may or may not be causal and therefore a hierarchy in which cause is situated within correlation provides a research program within which specific ideas may be tested without the rigidity of unnecessary commitment. The arrangement allows for awareness to be the world seen through itself. A final solution may be formulated from a number of solution ideas and include one or more of the above. These solution ideas, especially [1] and [3] define research projects on which I have done work
The fundamental problem of metaphysics is not so much the question of idealism vs. materialism and so on but the question of the meaning of “idea”, “being”…and, relative to humankind, not so much the given meaning or usage but are the potential meanings and usages…
…and potential, relative to humankind, does not mean possible but, rather, what is true but not yet known
…and the fundamental psychological issue of metaphysics is to use but not be wedded to given/received meanings, usages and knowledge
“Of all the neurobiological theories of consciousness I have seen, the most impressively worked out and the most profound is that of Gerald Edelman.”
But:
“…it is possible that a brain could have all these functional, behavioral features, including reentrant mapping, without thereby being conscious.”
And, recalling Crick’s ideas:
“…the problem is the same as the one encountered before: how do you get from all these structures and their functions to the qualitative states of sentience or awareness that all of us have.”
AM: For this critique by Searle to be significant and reasonable:
Explanation of subjectivity must be tractable on scientific/material accounts
The problem is, of course, the explanatory gap between subjectivity and brain/matter that, in scientific description, is devoid of matter
Tractability: the gap is merely a gap and not an unbridgeable chasm
There should be a specification of the kind of criteria that an explanation should satisfy. This follows from the fact that it is not obvious what these criteria might be - presumably the system should have certain kinds of effects or causal powers…but what are these powers and how will we demonstrate that those causal powers, even if equal to the causal powers of consciousness, imply consciousness? Of course, the criteria may not yet be known and may be tied to the explanation
It seems to me that that criterion [set] is going to have to be magic [in the sense of insight, a change of Gestalt…but not in the abracadabra sense]…or plain obvious [seen but not recognized…]; Searle’s “consciousness is a feature of the brain” is a candidate but is not yet very helpful
The main ideas of Roger Penrose as presented in The Emperor’s New Mind, 1989 and Shadows of the Mind, 1994, are:
Minds are capable of non-computable [non-algorithmic] processes, therefore minds cannot even be simulated by computers or algorithms
The mathematical theories of classical and today’s quantum physics are computable and therefore the physical elements underlying minds and mental processes must include phenomena that will require description by some new and future non-computable physical theory
Penrose extends the argument in [a] to quantum computers defined as machines that obey the rules of today’s quantum mechanics. The argument is that this class of quantum computers are equivalent to the class of classical computers that are enhanced by a randomizing element. Therefore quantum computers are also limited to computable operations. This is also the argument for the computability of quantum mechanics to date
Penrose’s candidate for the new physics is quantum gravity
Obviously, this discussion omits a wealth of detail and subtlety including some crucial issues such as how a neuron might deploy quantum behavior. The problem with the latter is the issue of the superposition of neuron computation given the disturbance of the environment by each neuron signal
Briefly, the proposed and tentative resolution is “quantum coherence in microtubules.”
Searle’s responses:
“…from the fact that a certain type of computational simulation cannot be given of a process under one description it does not follow that another type of computational simulation cannot be given of the very same process under another description.” [p. 71]
And :”An intelligent version of Weak AI[3] should attempt to simulate actual cognitive processes. Now, one way to simulate cognitive processes is to simulate brain processes…” [p. 72] The point to Searle’s argument is that simulation of brain processes is not a simulation at the level of mathematical reasoning. Penrose’s argument, according to Searle, “shows that there cannot be a computational simulation at the level of mathematical reasoning.” Searle continues, “Fine, but it does not follow that there cannot be computational simulation of the very same sequence of events at the level of brain processes, and we know that must be such a level of brain processes because we know that any mathematical reasoning must be realized in the brain.” [p. 74]
“How is it even conceivable that his hypothetical quantum mechanics could cause conscious processes? What might the causal mechanisms be?” [p. 84]
“In any case the motivation for his whole line of reasoning is based on a fallacy…there is no problem whatever in supposing that a set of relations that are noncomputable at some level of description can be the result of processes that are computable at some other level.” [p.85]
No summary
Traditional philosophy of mind:
Monists
Idealists
Materialists
Dualists
Substance dualists
Property dualists; The same substance, e.g. a human being, can have both types of property
Although most people are probably dualists, most professionals in philosophy, psychology, AI, neurobiology and cognitive science are materialists; Thomas Nagel and Colin McGinn are among the relatively few property dualists and the very few substance dualists are those such as Sir John Eccles who have a religious commitment to the soul
A problem with materialism: a lot of mental data - pains, beliefs, desires, thoughts,… are left over after the material facts. Materialists think they have to get rid of mental facts by reducing them to material phenomena or showing that don’t exist. Even when they are reduced, mental facts continue to factually present, to be psychologically significant and to be causally efficient despite the alleged reduction; and elimination is obviously false
Brief history of 20th
century reductive materialism
Radical or logical behaviorism - in contrast to the research program of methodological behaviorism - insists that there are no mental facts, no mental phenomena. Mental states are [and mental terms are at most terms that refer to] patterns of behavior where behavior is body movement without a mental component. Chief proponents: Gilbert Ryle, Carl Gustav Hempel
Problems
Intuitively false: pain and pain behavior are different
Omits causal relations: belief causes behavior…in contrast to the belief is “behavior” of behaviorism
Circularity: cannot be analyzed without reference to other mental states [beliefs and desires require each other]
The Identity Theory or Physicalism: mental states are brain states…J.J.C. Smart and others
Problems
What characteristic of brain states makes them mental - as opposed to brain states that are not mental?
It is too restrictive to say that only the brain can have mental states
Functionalism: mental states are physical states but it is their causal relations that make them mental. Any system with the right causal relations is mental
Resolves some of the objections to [1] and [2] above
Utterly implausible - it leaves the mind out of mind e.g. pain is not pain’s causal relations…but functionalism is the best form of materialism available and so is the most widely held philosophy o mind today. In the version linked to computers it is the dominant theory in cognitive science
Problems
Although brains are not necessarily the only things that can have minds, not everything that has the right causal relations has mental states - the Chinese Room argument. Recall that functionalism is also known as black box functionalism…if functionalism is interpreted in a way that eliminates the black box[es] and input-output relations at a certain level of description then it becomes physicalism
Leaves out qualia…the red-green inversion shows that different subjective states are functionally identical. Mental states are still [functional states are] physical states in functionalism
Does not how different physical states have the same causal relations
Strong AI: a version of functionalism in which the computational state of a computer is exactly like a functional state in a brain. Mental states are information processing states of [a program implemented in] the brain
Problems
Scientific commonsense: pains are qualitative experiences caused by specific neurobiological processes
According to functionalism, pains are physical states in brains or anything else with the right causal relations [read program]…the physical states don’t cause the pain, they are the pain
Philosophers sympathetic to the functionalist perspective have a choice when explaining consciousness: accept he irreducibility of consciousness and deny functionalism [Thomas Nagel] or keep functionalism and deny irreducibility [Dennett]
Chalmers’ position: he wants both functionalism and [property] dualism: functionalism [and strong AI] are adequate accounts of mind up to consciousness which must then be tacked on and which is not subject to functionalist analysis...Chalmers calls this “non-reductive functional dualism.” [p. 249]...”Cognition can be explained functionally; consciousness resists such explanation.”...Searle says:
This is peculiar because functionalism evolved to avoid irreducibility of mental phenomena and so avoid dualism
Chalmers uses standard arguments to prove functionalism can’t account for consciousness but does not accept the same arguments against functionalism in general
Although functional organization is not consciousness the two always go together - “As long as the functional organization is right conscious experience will be determined.”
“The Conscious Mind” is a symptom of desperation in cognitive studies: the main research program - computer functionalism - would be hard to give up but a remotely plausible functional account of consciousness has not been given
Chalmers’ “solution” is to keep the ideology [functionalism] and accept consciousness and its irreducibility, which the cognitive studies community is largely ready to accept
Chalmers argues that consciousness is not physical because it is not logically supervenient on the physical
...and that there are two aspects to mental states - a functionalist one [in which pain, for example, is not conscious] and the subjective one in which pain is a conscious sensation.
...the relation between the two occurs on account of the “principle of structural coherence” - there is a 1-1 relation between the structure of consciousness and functional organization
Chalmers argument for the principle: without it conscious states could change without changing behavior [functional organization] but this is impossible since change in mental content must be mirrored in a change in functional organization – which does not follow since it is what was to be proved and since functional organization is not brain state
The implausibility of Chalmers’ position
As noted above, psychological terms have two quite distinct meanings - a functionalist one referring to material entities and a conscious meaning referring to conscious entities
Consciousness is explanatorily relevant to everything physical that happens in the world. In particular, consciousness is irrelevant to human behavior
Even your own judgments about your consciousness cannot be explained - neither entirely nor even in part - by your consciousness
Consciousness is everywhere - the absurd view called pan-psychism
Chalmers’ responses
Brain causes consciousness is equally implausible [Searle: but that’s irrelevant since it’s empirically true
Shifts the burden of argument: critics should prove why not pan-psychism
Searle’s response
The absurdities follow from joining property dualism to the contemporary functionalist-computationalist account of mind
By dropping property dualism and functionalism:
There are not two definitions of psychological terms. Rather, only systems capable of consciousness can have any psychology at all
There is no compulsion to say that consciousness is explanatorily irrelevant
As a result consciousness is essential where its own representation is concerned
There is not the slightest reason to adopt pan-psychism
Resolution
Assuming the Cartesian vocabulary and modern science forces materialism, which omits consciousness and so forces some false strategy like functionalism. So: jettison the Cartesian categories and recognize that consciousness is a biological process
No summary
Some final suggestions
The philosophical importance of computers, like that of any new tool, is exaggerated. This explains the attachment to AI and computer functionalism, which is anti-biological
Brains matter crucially for consciousness
Crick, Edelman and Penrose are on the right track
There is no unifying principle of neuroscience today
One approach: through the unconscious e.g. what is the difference between blind sight and conscious sight