A re-redated post.
I have redated this post because Darek has responded to Jim, but it has been awhile (13 days) since it was up.
A few years ago Darek Barefoot sent me a defense of the Argument from Reason. I ran across it lately, and asked him if I could share it on the blog. He said yes, so here it is.
Simulating Sleep: A Thought Experiment to Demonstrate the Argument from Reason
by Darek Barefoot
Under a physicalist model of reality, all connections are instances of cause and effect (quantum events having a peculiar "disconnectedness"). Whatever the mind or brain comes to know about reality must be through such cause-and-effect connections with the events and objects that are known. We know that an object is red, with a high degree of probability, because it looks red to us. Some connections are less direct, and might be called "detections." We come to know the barometric pressure at a given moment because what is obvious to our senses when we look at the dial of a barometer is causally connected with a physical state difficult or impossible to sense directly. The cause and effect relationship between what we see on the dial and actual atmospheric pressure is critical. To repeat, under physicalistic assumptions all acts of knowing must be causally connected with the state of the object being known; no other type of connection is available.
Physicalists such as Daniel Dennett insist that even consciousness, to the extent that the word describes anything real, is a causally driven physical activity and nothing more. What we think of as conscious functions such as sensation and reason are interpreted as behaviors. For convenience we might divide these behaviors into those that are external and therefore obvious to any observer, such as walking and talking, and those that are internal actions of the brain that must be detected, such as the electrical changes measured by an EEG.
Logical connections, however, defy being equated with or reduced to chains of cause and effect. We can demonstrate this incompatibility with the following thought experiment. Suppose I lie down on a bed, close my eyes, relax my limbs and deliberately begin to breathe in the deep, regular pattern that we associate with asleep. Now, as I lie on the bed under these conditions, how do I know that I am awake and not asleep? I can sense that the position of my body and my external behavior are consistent with sleep. If a third party were to walk into a room and observe my behavior, they would think it more likely than not that I was asleep.
If I know myself to be awake, in spite of sensing my bodily behavior to be that typical of sleep, I must under physicalist assumptions be sensing or detecting the other behavioral component, my brain activity. After all, these two types of behavior allegedly comprise everything we call the state of being awake, and my act of knowing myself to be awake must be linked to my "awake" behavior, uninterruptedly, by means of cause and effect. The trouble is, I can offer no sensory account of what my brain is doing. I cannot see or hear any part of my brain, nor can I claim to see or hear electrical or chemical changes going on in it. I cannot "feel" my brain in the somatosensory way I feel the position of my limbs or the way I feel my heart beating when my pulse is rapid.
To know things about the state of my brain by causal means through detection, as opposed to direct sensation, would require special instruments. For example, suppose an EEG were set up in the room where I am lying down and that I were connected to it. Suppose further that instead of just a graph it
generated an audio signal in the form of beeps and that from the timing of these beeps it could be determined whether the person hooked up to the machine was awake or asleep. Even lying on the bed with my eyes closed I could listen to the beeps and detect my brain activity to be that of someone who is awake. It is important to note that this is public, not private, information. A person walking into the room could also detect from the beeps that I was awake in spite of observing that my bodily behavior was consistent with sleep.
The ability of an EEG to convey to me my brain state is well and good, but returning to my original situation in the room, I have no EEG and cannot detect my brain activity. I have only the messages I am receiving from my body as effects in the form of sensations. To the extent that these sensations "say" anything about my condition with respect to my being asleep or awake, they say "probably asleep." How, then, do I nevertheless know myself to be awake? I do so by logical means. I am feeling the state of my body, and since I can only feel things when I am awake, it is overwhelmingly probable that I am awake. Logic transforms "probably asleep" to "probably awake," and I am content to put faith in this mysterious alchemy. How is this happening?
Perhaps I was mistaken about the causal inputs, the "sensations," I am receiving. Perhaps the logically active part of my brain, in the cerebral cortex, is actually connected by cause and effect means with "awake" activity in some other part such as the mid-brain. In reality, then, the way I know I am awake is by sensing the awake state of my brain, or at least part of it. But what about the syllogism that I (mistakenly) thought was means by which I know I am awake: "I only experience bodily sensations when I am awake; I am experiencing bodily sensations; therefore I am awake." Is the syllogism still sound? If the syllogism is sound and if it is different than the sensing of an awake state of one part of my brain by another part, then I was not mistaken after all. But the implication is dire for any physicalist model of the situation, because it means that I can know about the awake state of my brain without any sensory, causal connection to that state. It should go without saying that the brain activity entailed by my act of knowing cannot be causally connected to itself; the event sequence involved cannot be its own cause.
Few options are left, physicalistically speaking. It might be claimed that I do not in fact know that I am awake in the circumstances specified. Physicalists who wish to ply that argument are free to do so, and the rest of us may be excused for paying them little attention. The other strategy is to identify the syllogism with the act of sensing of an awake state in some part of my brain. This would have strange implications, to say the least. My means of knowing that I am awake would actually be not reason distinct from sensation but reason as sensation--and as a sensation different that the one the syllogism identifies, to boot. Remember, I thought that I arrived at my knowledge by reasoning based on sensations originating in my body. Can any of our knowledge, including cognitive science, survive if syllogisms are equated with sensations? Is logic, as distinct from simple sensation, a kind of illusion? That can hardly be true if the word "true" is to retain any meaning.
It is pretty routine for us to differentiate between sensations and syllogisms. Are the sensations entailed in seeing and smelling a rose the equivalent of propositions inferred logically about a rose? For one thing, syllogisms and propositions may be sound or unsound, true or false. Sensations, on the other hand, are not true or false or correct or incorrect, they simply "are." As Ayer observed, "A sensation is not the sort of thing which can be doubtful or not doubtful. A sensation simply occurs. What are doubtful are the propositions which refer to our sensations." To claim that there is no sharp divide between sensations and syllogisms is, at the bare minimum, to assume a heavy burden of explanation.
Let's imagine, instead of me lying on a bed, an electrical device with a meter that displays the level of incoming voltage. The voltage meter might due to unexpected mechanical events read "0" when in fact there was still an electrical current present in the device. Let's roughly compare this circumstance to my appearing to be asleep when I am not. Let's also suppose that, forseeing this possibility, the makers of the device have installed a small red indicator light that stays lit when any current is present, even if the voltage meter happens to read "0." There might even be a small sign beneath the light reading, "power on." Is there any distinction in principle to be made between the manner of operation of the voltage meter and that of the indicator light? Both undergo an obvious physical change when electrical current flows through them. We may call the branching circuit to the indicator light a "logic circuit," but only as a subjective attribution. One circuit in the device is no more "logical" than another. Nor does a distinction in principle appear with increasing complexity of the device. Even if the indicator light were replaced by a chip with an LCD display that read, "Beware, I have determined that current is present in my circuits!," it would remain a sensor. In principle, a sensor is a sensor. It is impossible to distinguish between types of sensors in the same way we can between sensations and syllogisms.
The simulated sleep experiment is designed to make obvious the gulf between sensation and reason that always exists but may be harder to differentiate when impression and conclusion coincide more closely. Other examples can be offered, however. If I look through red-tinted glasses I understand that objects that are not red will look red and red objects will look white. My knowledge does not cause me to experience red when I see white, however, nor do I have to stop and picture a white-appearing object as red in my mind to understand logically that it must really be red. Nor does my experience of knowingly viewing objects through red-tinted glasses amount to sensory dissonance. It is not the same as, say, looking at what appears to be a melting ice cube and discovering with surprise that it is warm to the touch. "Looks white through red-tinted glasses, is therefore red," is in terms of raw sensory experience unfathomable, but it is a phenomenon that I have no difficulty coming to terms with as long as logic is available to me.
The simulated sleep experiment points up the difficulty physicalism has accounting not only for reason, but for consciousness as well. Consciousness in the context of the experiment is substantially synonymous with the state of being awake and is defined behaviorally along the same lines. As I point out above, there are three means of determining that I am conscious. Means No. 1 is to observe my waking or conscious behavior. Someone who sees me walking, talking and otherwise responding will know that I am conscious. I myself have access to that behavior by sensory means as well. I can feel my body moving and hear myself speaking. Means No. 2 is to detect my conscious brain activity, as by the EEG. Both I and an observer potentially have access to this information as well. Means No. 3 is my private experience as the basis of a logic transaction that obtains the information otherwise available by Means Nos. 1 and 2. The problem for physicalistic theories of consciousness is that they cannot accomodate "private" knowledge as objective, and Means No. 3 of determining whether I am conscious necessarily is private. If I decide to give any physical clues at all about my state to an observer, the observer would receive the information through Means No. 1. If the observer, on the other hand, resorts to instrumentation or any causally-based investigative method to determine my brain activity, the information he obtains will owe to Means No. 2. No advances in technology or cognitive science can remedy the problem unless they endow test subjects and observers with mental telephathy.
The irreconcilability of private knowledge with physicalism can be grasped through analogy. Suppose I am an astronomer who comes to know, by some power of my brain not entirely understandable to me, the precise position and orbit of a heretofore uncharted moon of Jupiter. I know this fact apart from anything that may be construed as observation of the moon or its effects. If I train my telescope on the right portion of the sky, I can say I have observed the moon to exist. If someone else happens to do the same, they will make the discovery as well. Before either observation is made, however, I and I alone know the moon exists, and I know it with the same degree of certainty that I know myself to exist. If, after another astronomer observes the moon, I were to tell him that I knew it was there previous to his discovery without being able to give him any observational account to justify this supposed insight of mine, he would likely regard me as a crank. Presumably the same astronomer would, on the other hand, have a different opinion if the object of knowledge were not a hypothetical moon of Jupiter but my own unobserved state of consciousness.
There must be a factor associated with what we call consciousness that is absent from physical events and objects as we encounter them externally. This factor has most often been associated with so-called qualia, the "what it's like" of experience. Famous expositions of "what it's like" to exist as a member of a particular animal species (Nagel, 1974) or to see colors (Jackson, 1982) make the fairly obvious point that there is something to experience that cannot be captured in a factual description. The ineffable "something" that comprises qualia is amorphous, objective in its existence but subjective as to its essence. Whether I know myself to be conscious as I lie on the bed is a question of hard fact. Either I know my condition or I do not. If I know myself to be conscious, then the source of my knowing is as objectively real as the knowledge itself.
To say that there is something more than physical cause and effect occuring in consciousness and reason is not to deny that in our experience they are conditional on certain physical states. Too much should not be made of the association. If I tampered with the components of a radio, the quality of the sound it produced would be effected. If I tampered with the radio forcefully, it would cease to produce sound at all. Only through a fallacy could I conclude from these facts that the broadcast heard over the radio originated in the radio itself. The analogy is imperfect, as all analogies are, but it remains true that the observed necessity of certain conditions for the occurrence of certain events does not confine the explanation of those events to the conditions alone. The existence of a body of water of a certain size may be a condition of having high and low tides, but a body of water does cause tides to occur simply by existing. If the brain is more like an interface than a stand-alone machine, then it cannot be in contact with the "mindless" entities we know as physical substances. It is easy to appreciate that this unsettling implication is more congruent with theism than with atheistic materialism.
The Argument from Reason was popularized by C.S. Lewis in his book Miracles (1960) and developed by others since. The experiment described here is an effort briefly to illustrate his thesis.
A. J. Ayer, Language, Truth and Logic (1952) 93.
Thomas Nagel, The Philosophical Review LXXXIII, 4 (October 1974) 435-50.
Frank Jackson, 'Epiphenomenal Qualia,' Philosophical Quarterly (April 1982) 127-136.
C. S. Lewis, Miracles (1960) 12-24.
For a good overview of the Argument from Reason, see Victor Reppert's article of the same name at www.infidels.org/library/modern/victor_reppert/reason.html.