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EPISTEMOLOGIST: Private mental states! Metaphysical hogwash! Look, I am
a practical epistemologist. Metaphysical problems about "mind" versus
"matter" arise only from epistemological confusions. Epistemology is the
true foundation of philosophy. But the trouble with all past epistemologists
is that they have been using wholly theoretical methods, and much of their
discussion degenerates into mere word games. While other epistemologists
have been solemnly arguing such questions as whether a man can be wrong when
he asserts that he believes such and such, I have discovered how to settle
such questions experimentally.
FRANK: How could you possibly decide such things empirically?
EPISTEMOLOGIST: By reading a person's thoughts directly.
FRANK: You mean you are telepathic?
EPISTEMOLOGIST: Of course not. I simply did the one obvious thing which
should be done, viz. I have constructed a brain-reading machine--known
technically as a cerebroscope--that is operative right now in this room and
is scanning every nerve cell in your brain. I thus can read your every
sensation and thought, and it is a simple objective truth that this book
does not seem red to you.
FRANK (thoroughly subdued): Goodness gracious, I really could have
sworn that the book seemed red to me; it sure seems that it seems read to
me!
EPISTEMOLOGIST: I'm sorry, but you are wrong again.
FRANK: Really? It doesn't even seem that it seems red to me? It sure
seems like it seems like it seems red to me!
EPISTEMOLOGIST: Wrong again! And no matter how many times you reiterate
the phrase "it seems like" and follow it by "the book is red" you will be
wrong.
FRANK: This is fantastic! Suppose instead of the phrase "it seems like"
I would say "I believe that." So let us start again at ground level. I
retract the statement "It seems red to me" and instead I assert "I believe
that this book is red." Is this statement true or false?
EPISTEMOLOGIST: Just a moment while I scan the dials of the
brain-reading machine--no, the statement is false.
FRANK: And what about "I believe that I believe that the book is red"?
EPISTEMOLOGIST (consulting his dials): Also false. And again, no matter
how many times you iterate "I believe," all these belief sentences are
false.
FRANK: Well, this has been a most enlightening experience. However, you
must admit that it is a little hard on me to realize that I am entertaining
infinitely many erroneous beliefs!
EPISTEMOLOGIST: Why do you say that your beliefs are erroneous?
FRANK: But you have been telling me this all the while!
EPISTEMOLOGIST: I most certainly have not!
FRANK: Good God, I was prepared to admit all my errors, and now you
tell me that my beliefs are not errors; what are you trying to do, drive me
crazy?
EPISTEMOLOGIST: Hey, take it easy! Please try to recall: When did I say
or imply that any of your beliefs are erroneous?
FRANK: Just simply recall the infinite sequence of sentences: (1) I
believe this book is red; (2) I believe that I believe this book is red; and
so forth. You told me that every one of those statements is false.
EPISTEMOLOGIST: True.
FRANK: Then how can you consistently maintain that my beliefs in all
these false statements are not erroneous?
EPISTEMOLOGIST: Because, as I told you, you don't believe any of them.
FRANK: I think I see, yet I am not absolutely sure.
EPISTEMOLOGIST: Look, let me put it another way. Don't you see that the
very falsity of each of the statements that you assert saves you from an
erroneous belief in the preceding one? The first statement is, as I told
you, false. Very well! Now the second statement is simply to the effect that
you believe the first statement. If the second statement were true, then you
would believe the first statement, and hence your belief about the first
statement would indeed be in error. But fortunately the second statement is
false, hence you don't really believe the first statement, so your belief in
the first statement is not in error. Thus the falsity of the second
statement implies you do not have an erroneous belief about the first; the
falsity of the third likewise saves you from an erroneous belief about the
second, etc.
FRANK: Now I see perfectly! So none of my beliefs were erroneous, only
the statements were erroneous.
EPISTEMOLOGIST: Exactly.
FRANK: Most remarkable! Incidentally, what color is the book really?
EPISTEMOLOGIST: It is red.
FRANK: What!
EPISTEMOLOGIST: Exactly! Of course the book is red. What's the matter
with you, don't you have eyes?
FRANK: But didn't I in effect keep saying that the book is red all
along?
EPISTEMOLOGIST: Of course not! You kept saying it seems red to you, it
seems like it seems red to you, you believe it is red, you believe that you
believe it is red, and so forth. Not once did you say that it is red. When I
originally asked you "What color is the book?" if you had simply answered
"red," this whole painful discussion would have been avoided.
Scene 3. Frank comes back several months later to the home of the
epistemologist.
EPISTEMOLOGIST: How delightful to see you! Please sit down.
FRANK (seated): I have been thinking of our last discussion, and there
is much I wish to clear up. To begin with, I discovered an inconsistency in
some of the things you said.
EPISTEMOLOGIST: Delightful! I love inconsistencies. Pray tell!
FRANK: Well, you claimed that although my belief sentences were false,
I did not have any actual beliefs that are false. If you had not admitted
that the book actually is red, you would have been consistent. But your very
admission that the book is red, leads to an inconsistency.
EPISTEMOLOGIST: How so?
FRANK: Look, as you correctly pointed out, in each of my belief
sentences "I believe it is red," "I believe that I believe it is red," the
falsity of each one other than the first saves me from an erroneous belief
in the proceeding one. However, you neglected to take into consideration the
first sentence itself. The falsity of the first sentence "I believe it is
red," in conjunction with the fact that it is red, does imply that I do have
a false belief.
EPISTEMOLOGIST: I don't see why.
FRANK: It is obvious! Since the sentence "I believe it is red" is
false, then I in fact believe it is not red, and since it really is red,
then I do have a false belief. So there!
EPISTEMOLOGIST (disappointed): I am sorry, but your proof obviously
fails. Of course the falsity of the fact that you believe it is red implies
that you don't believe it is red. But this does not mean that you believe it
is not red!
FRANK: But obviously I know that it either is red or it isn't, so if I
don't believe it is, then I must believe that it isn't.
EPISTEMOLOGIST: Not at all. I believe that either Jupiter has life or
it doesn't. But I neither believe that it does, nor do I believe that it
doesn't. I have no evidence one way or the other.
FRANK: Oh well, I guess you are right. But let us come to more
important matters. I honestly find it impossible that I can be in error
concerning my own beliefs.
EPISTEMOLOGIST: Must we go through this again? I have already patiently
explained to you that you (in the sense of your beliefs, not your
statements) are not in error.
FRANK: Oh, all right then, I simply do not believe that even the
statements are in error. Yes, according to the machine they are in error,
but why should I trust the machine?
EPISTEMOLOGIST: Whoever said you should trust the machine?
FRANK: Well, should I trust the machine?
EPISTEMOLOGIST: That question involving the word "should" is out of my
domain. However, if you like, I can refer you to a colleague who is an
excellent moralist--he may be able to answer this for you.
FRANK: Oh come on now, I obviously didn't mean "should" in a moralistic
sense. I simply meant "Do I have any evidence that this machine is
reliable?"
EPISTEMOLOGIST: Well, do you?
FRANK: Don't ask me! What I mean is should you trust the machine?
EPISTEMOLOGIST: Should I trust it? I have no idea, and I couldn't care
less what I should do.
FRANK: Oh, your moralistic hangup again. I mean, do you have evidence
that the machine is reliable?
EPISTEMOLOGIST: Well of course!
FRANK: Then let's get down to brass tacks. What is your evidence?
EPISTEMOLOGIST: You hardly can expect that I can answer this for you in
an hour, a day, or a week. If you wish to study this machine with me, we can
do so, but I assure you this is a matter of several years. At the end of
that time, however, you would certainly not have the slightest doubts about
the reliability of the machine.
FRANK: Well, possibly I could believe that it is reliable in the sense
that its measurements are accurate, but then I would doubt that what it
actually measures is very significant. It seems that all it measures is
one's physiological states and activities.
EPISTEMOLOGIST: But of course, what else would you expect it to
measure?
FRANK: I doubt that it measures my psychological states, my actual
beliefs.
EPISTEMOLOGIST: Are we back to that again? The machine does measure
those physiological states and processes that you call psychological states,
beliefs, sensations, and so forth.
FRANK: At this point I am becoming convinced that our entire difference
is purely semantical. All right, I will grant that your machine does
correctly measure beliefs in your sense of the word "belief," but I don't
believe that it has any possibility of measuring beliefs in my sense of the
word "believe." In other words I claim that our entire deadlock is simply
due to the fact that you and I mean different things by the word "belief."
EPISTEMOLOGIST: Fortunately, the correctness of your claim can be
decided experimentally. It so happens that I now have two brain-reading
machines in my office, so I now direct one to your brain to find out what
you mean by "believe" and now I direct the other to my own brain to find out
what I mean by "believe," and now I shall compare the two readings. Nope,
I'm sorry, but it turns out that we mean exactly the same thing by the word
"believe."
FRANK: Oh, hang your machine! Do you believe we mean the same thing by
the word "believe"?
EPISTEMOLOGIST: Do I believe it? Just a moment while I check with the
machine. Yes, it turns out I do believe it.
FRANK: My goodness, do you mean to say that you can't even tell me what
you believe without consulting the machine?
EPISTEMOLOGIST: Of course not.
FRANK: But most people when asked what they believe simply tell you.
Why do you, in order to find out your beliefs, go through the fantastically
roundabout process of directing a thought-reading machine to your own brain
and then finding out what you believe on the basis of the machine readings?
EPISTEMOLOGIST: What other scientific, objective way is there of
finding out what I believe?
FRANK: Oh, come now, why don't you just ask yourself?
EPISTEMOLOGIST (sadly): It doesn't work. Whenever I ask myself what I
believe, I never get any answer!
FRANK: Well, why don't you just state what you believe?
EPISTEMOLOGIST: How can I state what I believe before I know what I
believe?
FRANK: Oh, to hell with your knowledge of what you believe; surely you
have some idea or belief as to what you believe, don't you?
EPISTEMOLOGIST: oOf course I have such a belief. But how do I find out
what this belief is?
FRANK: I am afraid we are getting into another infinite regress. Look,
at this point I am honestly beginning to wonder whether you may be going
crazy.
EPISTEMOLOGIST: Let me consult the machine. Yes, it turns out that I
may be going crazy.
FRANK: Good God, man, doesn't this frighten you?
EPISTEMOLOGIST: Let me check! Yes, it turns out that it does frighten
me.
FRANK: Oh please, can't you forget this damned machine and just tell me
whether you are frightened or not?
EPISTEMOLOGIST: I just told you that I am. However, I only learned of
this from the machine.
FRANK: I can see that it is utterly hopeless to wean you away from the
machine. Very well, then, let us play along with the machine some more. Why
don't you ask the machine whether your sanity can be saved?
EPISTEMOLOGIST: Good idea! Yes, it turns out that it can be saved.
FRANK: And how can it be saved?
EPISTEMOLOGIST: I don't know, I haven't asked the machine.
FRANK: Well, for God's sake, ask it!
EPISTEMOLOGIST: Good idea. It turns out that...
FRANK: It turns out what?
EPISTEMOLOGIST: It turns out that...
FRANK: Come on now, it turns out what?
EPISTEMOLOGIST: This is the most fantastic thing I have ever come
across! According to the machine the best thing I can do is to cease to
trust the machine!
FRANK: Good! What will you do about it?
EPISTEMOLOGIST: How do I know what I will do about it, I can't read the
future?
FRANK: I mean, what do you presently intend to do about it?
EPISTEMOLOGIST: Good question, let me consult the machine. According to
the machine, my current intentions are in complete conflict. And I can see
why! I am caught in a terrible paradox! If the machine is trustworthy, then
I had better accept its suggestion to distrust it. But if I distrust it,
then I also distrust its suggestion to distrust it, so I am really in a
total quandary.
FRANK: Look, I know of someone who I think might be really of help in
this problem. I'll leave you for a while to consult him. Au revoir!
Scene 4. (Later in the day at a psychiatrist's office.)
FRANK: Doctor, I am terribly worried about a friend of mine. He calls
himself an "experimental epistemologist."
DOCTOR: Oh, the experimental epistemologist. There is only one in the
world. I know him well!
FRANK: That is a relief. But do you realize that he has constructed a
mind-reading device that he now directs to his own brain, and whenever one
asks him what he thinks, believes, feels, is afraid of, and so on, he has to
consult the machine first before answering? Don't you think this is pretty
serious?
DOCTOR: Not as serious as it might seem. My prognosis for him is
actually quite good.
FRANK: Well, if you are a friend of his, couldn't you sort of keep an
eye on him?
DOCTOR: I do see him quite frequently, and I do observe him much.
However, I don't think he can be helped by so-called "psychiatric
treatment." His problem is an unusual one, the sort that has to work itself
out. And I believe it will.
FRANK: Well, I hope your optimism is justified. At any rate I sure
think I need some help at this point!
DOCTOR: How so?
FRANK: My experiences with the epistemologist have been thoroughly
unnerving! At this point I wonder if I may be going crazy; I can't even have
confidence in how things appear to me. I think maybe you could be helpful
here.
DOCTOR: I would be happy to but cannot for a while. For the next three
months I am unbelievably overloaded with work. After that, unfortunately, I
must go on a three-month vacation. So in six months come back and we can
talk this over.
Scene 5. (Same office, six months later.)
DOCTOR: Before we go into your problems, you will be happy to hear that
your friend the epistemologist is now completely recovered.
FRANK: Marvelous, how did it happen?
DOCTOR: Almost, as it were, by a stroke of fate--and yet his very
mental activities were, so to speak, part of the "fate." What happened was
this: For months after you last saw him, he went around worrying "should I
trust the machine, shouldn't I trust the machine, should I, shouldn't I,
should I, shouldn't I." (He decided to use the word "should" in your
empirical sense.) He got nowhere! So he then decided to "formalize" the
whole argument. He reviewed his study of symbolic logic, took the axioms of
first-order logic, and added as nonlogical axioms certain relevant facts
about the machine. Of course the resulting system was inconsistent--he
formally proved that he should trust the machine if and only if he
shouldn't, and hence that he both should and should not trust the machine.
Now, as you may know, in a system based on classical logic (which is the
logic he used), if one can prove so much as a single contradictory
proposition, then one can prove any proposition, hence the whole system
breaks down. So he decided to use a logic weaker than classical logic--a
logic close to what is known as "minimal logic"--in which the proof of one
contradiction does not necessarily entail the proof of every proposition.
However, this system turned out too weak to decide the question of whether
or not he should trust the machine. Then he had the following bright idea.
Why not use classical logic in his system even though the resulting system
is inconsistent? Is an inconsistent system necessarily useless? Not at all!
Even though given any proposition, there exists a proof that it is true and
another proof that it is false, it may be the case that for any such pair of
proofs, one of them is simply more psychologically convincing than the
other, so simply pick the proof you actually believe! Theoretically the idea
turned out very well--the actual system he obtained really did have the
property that given any such pair of proofs, one of them was always
psychologically far more convincing than the other. Better yet, given any
pair of contradictory propositions, all proofs of one were more convincing
than any proof of the other. Indeed, anyone except the epistemologist could
have used the system to decide whether the machine could be trusted. But
with the epistemologist, what happened was this: He obtained one proof that
he should trust the machine and another proof that he should not. Which
proof was more convincing to him, which proof did he really "believe"? The
only way he could find out was to consult the machine! But he realized that
this would be begging the question, since his consulting the machine would
be a tacit admission that he did in fact trust the machine. So he still
remained in a quandary.
FRANK: So how did he get out of it?
DOCTOR: Well, here is where fate kindly interceded. Due to his absolute
absorption in the theory of this problem, which consumed about his every
waking hour, he became for the first time in his life experimentally
negligent. As a result, quite unknown to him, a few minor units of his
machine blew out! Then, for the first time, the machine started giving
contradictory information--not merely subtle paradoxes, but blatant
contradictions. In particular, the machine one day claimed that the
epistemologist believed a certain proposition and a few days later claimed
he did not believe that proposition. And to add insult to injury, the
machine claimed that he had not changed his belief in the last few days.
This was enough to simply make him totally distrust the machine. Now he is
fit as a fiddle.
FRANK: This is certainly the most amazing thing I have ever heard! I
guess the machine was really dangerous and unreliable all along.
DOCTOR: Oh, not at all; the machine used to be excellent before the
epistemologist's experimental carelessness put it out of whack.
FRANK: Well, surely when I knew it, it couldn't have been very
reliable.
DOCTOR: Not so, Frank, and this brings us to your problem. I know about
your entire conversation with the epistemologist--it was all tape-recorded.
FRANK: Then surely you realize the machine could not have been right
when it denied that I believed the book was red.
DOCTOR: Why not?
FRANK: Good God, do I have to go through all this nightmare again? I
can understand that a person can be wrong if he claims that a certain
physical object has a certain property, but have you ever known a single
case when a person can be mistaken when he claims to have or not have a
certain sensation?
DOCTOR: Why, certainly! I once knew a Christian Scientist who had a
raging toothache; he was frantically groaning and moaning all over the
place. When asked whether a dentist might not cure him, he replied that
there was nothing to be cured. Then he was asked, "But do you not feel
pain?" He replied, "No, I do not feel pain; nobody feels pain, there is no
such thing as pain, pain is only an illusion." So here is a case of a man
who claimed not to feel pain, yet everyone present knew perfectly well that
he did feel pain. I certainly don't believe he was lying, he was just simply
mistaken.
FRANK: Well, all right, in a case like that. But how can one be
mistaken if one asserts his belief about the color of a book?
DOCTOR: I can assure you that without access to any machine, if I asked
someone what color is this book, and he answered, "I believe it is red," I
would be very doubtful that he really believed it. It seems to me that if he
really believed it, he would answer, "It is red" and not "I believe it is
red" or "It seems red to me." The very timidity of his response would be
indicative of his doubts.
FRANK: But why on earth should I have doubted that it was red?
DOCTOR: You should know that better than I. Let us see now, have you
ever in the past had reason to doubt the accuracy of your sense perception?
FRANK: Why, yes. A few weeks before visiting the epistemologist, I
suffered from an eye disease, which did make me see colors falsely. But I
was cured before my visit.
DOCTOR: Oh, so no wonder you doubted it was red! True enough, your eyes
perceived the correct color of the book, but your earlier experience
lingered in your mind and made it impossible for you to really believe it
was red. So the machine was right!
FRANK: Well, all right, but then why did I doubt that I believed it was
true?
DOCTOR: Because you didn't believe it was true, and unconsciously you
were smart enough to realize the fact. Besides, when one starts doubting
one's own sense perceptions, the doubt spreads like an infection to higher
and higher levels of abstraction until finally the whole belief system
becomes one doubting mass of insecurity. I bet that if you went to the
epistemologist's office now, and if the machine were repaired, and you now
claimed that you believe the book is red, the machine would concur.
No, Frank, the machine is--or, rather, was--a good one. The
epistemologist learned much from it, but misused it when he applied it to
his own brain. He really should have known better than to create such an
unstable situation. The combination of his brain and the machine each
scrutinizing and influencing the behavior of the other led to serious
problems in feedback. Finally the whole system went into a cybernetic
wobble. Something was bound to give sooner or later. Fortunately, it was the
machine.
FRANK: I see. One last question, though. How could the machine be
trustworthy when it claimed to be untrustworthy?
DOCTOR: The machine never claimed to be untrustworthy, it only claimed
that the epistemologist would be better off not trusting it. And the machine
was right.
--------
If Smullyan's nightmare strikes you as too outlandish to be convincing,
consider a more realistic fable--not a true story, but surely possible:
Once upon a time there were two coffee tasters, Mr. Chase and Mr.
Sanborn, who worked for Maxwell House. Along with half a dozen other coffee
tasters, their job was to ensure that the taste of Maxwell House stayed
constant, year after year. One day, about six years after Mr. Chase had come
to work for Maxwell House, he cleared his throat and confessed to Mr.
Sanborn:
"You know, I hate to admit it, but I'm not enjoying this work any more.
When I came to Maxwell House six years ago, I thought Maxwell House coffee
was the best-tasting coffee in the world. I was proud to have a share in the
responsibility for preserving that flavor over the years. And we've done our
job well; the coffee tastes today just the way it tasted when I arrived.
But, you know, I no longer like it! My tastes have changed. I've become a
more sophisticated coffee drinker. I no longer like that taste at all."
Sanborn greeted this revelation with considerable interest. "It's funny
you should mention it," he replied, "for something rather similar has
happened to me. When I arrived here, shortly before you did, I, like you,
thought Maxwell House coffee was tops in flavor. And now I, like you, really
don't care for the coffee we're making. But my tastes haven't changed; my...
tasters have changed. That is, I think something has gone wrong with my
taste buds or something--you know, the way your taste buds go off when you
take a bite of pancakes and maple syrup and then go back to your orange
juice? Maxwell House coffee doesn't taste to me the way it used to taste; if
only it did, I'd still love it, for I still think that taste is the best
taste in coffee. Now, I'm not saying we haven't done our job well. You other
guys all agree that the taste is the same, so it must be my problem alone. I
guess I'm no longer cut out for this work."
Chase and Sanborn are alike in one way. Both used to like Maxwell House
coffee; now neither one likes it. But they claim to be different in another
way: Maxwell House tastes to Chase the way it always did, but not so for
Sanborn. The difference seems familiar and striking, yet when they confront
each other, they may begin to wonder if their cases arc really all that
different. "Could it be," Chase might wonder, "that Mr. Sanborn is really in
my predicament and just hasn't noticed the gradual rise in his standards and
sophistication as a coffee taster?" "Could it be," Sanborn might wonder,
"that Mr. Chase is kidding himself when he says the coffee tastes just the
same to him as it used to?"
Do you remember your first sip of beer? Terrible! How could anyone like
that stuff? But beer, you reflect, is an acquired taste; one gradually
trains oneself--or just comes--to enjoy that flavor. What flavor? The flavor
of that first sip? No one could like that flavor! Beer tastes different to
the experienced beer drinker. Then beer isn't an acquired taste; one doesn't
learn to like that first taste; one gradually comes to experience a
different, and likable, taste. Had the first sip tasted that way, you would
have liked beer wholeheartedly from the beginning!
Perhaps, then, there is no separating the taste from the response to
the taste, the judgment of good or bad. Then Chase and Sanborn might be just
alike, and simply be choosing slightly different ways of expressing
themselves. But if they were just alike, then they'd actually both be wrong
about something, for they each have sincerely denied that they are like the
other. Is it conceivable that each could have inadvertently misdescribed his
own case and described the other's instead? Perhaps Chase is the one whose
taste buds have changed, while Sanborn is the sophisticate. Could they be
that wrong?
Some philosophers--and other people--have thought that a person simply
cannot be wrong about such a matter. Everyone is the final and unimpeachable
arbiter of how it is with him; if Chase and Sanborn have spoken sincerely,
and have made no unnoticed slips of language, and if both know the meanings
of their words, they must have expressed the truth in each case. Can't we
imagine tests that would tend to confirm their different tales? If Sanborn
does poorly on discrimination tests he used to pass with flying colors, and
if, moreover, we find abnormalities in his taste buds (it's all that
Szechuan food he's been eating lately, we discover), this will tend to
confirm his view of his situation. And if Chase passes all those tests
better than he used to, and exhibits increased knowledge of coffee types and
a great interest in their relative merits and peculiar characteristics, this
will support his view of himself. But if such tests could support Chase s
and Sanborn's authority, failing them would have to undermine their
authority. If Chase passed Sanborn's tests and Sanborn passed Chase's, each
would have doubt cast on his account--if such tests have any bearing at all
on the issue.
Another way of putting the point is that the price you pay for the
possibility of confirming your authority is the outside chance of being
discredited. "I know what I like," we are all prepared to insist, "and I
know what it's like to be me!" Probably you do, at least about some matters,
but that is something to be checked in performance. Maybe, just maybe,
you'll discover that you really don't know as much as you thought you did
about what it is like to be you.
a practical epistemologist. Metaphysical problems about "mind" versus
"matter" arise only from epistemological confusions. Epistemology is the
true foundation of philosophy. But the trouble with all past epistemologists
is that they have been using wholly theoretical methods, and much of their
discussion degenerates into mere word games. While other epistemologists
have been solemnly arguing such questions as whether a man can be wrong when
he asserts that he believes such and such, I have discovered how to settle
such questions experimentally.
FRANK: How could you possibly decide such things empirically?
EPISTEMOLOGIST: By reading a person's thoughts directly.
FRANK: You mean you are telepathic?
EPISTEMOLOGIST: Of course not. I simply did the one obvious thing which
should be done, viz. I have constructed a brain-reading machine--known
technically as a cerebroscope--that is operative right now in this room and
is scanning every nerve cell in your brain. I thus can read your every
sensation and thought, and it is a simple objective truth that this book
does not seem red to you.
FRANK (thoroughly subdued): Goodness gracious, I really could have
sworn that the book seemed red to me; it sure seems that it seems read to
me!
EPISTEMOLOGIST: I'm sorry, but you are wrong again.
FRANK: Really? It doesn't even seem that it seems red to me? It sure
seems like it seems like it seems red to me!
EPISTEMOLOGIST: Wrong again! And no matter how many times you reiterate
the phrase "it seems like" and follow it by "the book is red" you will be
wrong.
FRANK: This is fantastic! Suppose instead of the phrase "it seems like"
I would say "I believe that." So let us start again at ground level. I
retract the statement "It seems red to me" and instead I assert "I believe
that this book is red." Is this statement true or false?
EPISTEMOLOGIST: Just a moment while I scan the dials of the
brain-reading machine--no, the statement is false.
FRANK: And what about "I believe that I believe that the book is red"?
EPISTEMOLOGIST (consulting his dials): Also false. And again, no matter
how many times you iterate "I believe," all these belief sentences are
false.
FRANK: Well, this has been a most enlightening experience. However, you
must admit that it is a little hard on me to realize that I am entertaining
infinitely many erroneous beliefs!
EPISTEMOLOGIST: Why do you say that your beliefs are erroneous?
FRANK: But you have been telling me this all the while!
EPISTEMOLOGIST: I most certainly have not!
FRANK: Good God, I was prepared to admit all my errors, and now you
tell me that my beliefs are not errors; what are you trying to do, drive me
crazy?
EPISTEMOLOGIST: Hey, take it easy! Please try to recall: When did I say
or imply that any of your beliefs are erroneous?
FRANK: Just simply recall the infinite sequence of sentences: (1) I
believe this book is red; (2) I believe that I believe this book is red; and
so forth. You told me that every one of those statements is false.
EPISTEMOLOGIST: True.
FRANK: Then how can you consistently maintain that my beliefs in all
these false statements are not erroneous?
EPISTEMOLOGIST: Because, as I told you, you don't believe any of them.
FRANK: I think I see, yet I am not absolutely sure.
EPISTEMOLOGIST: Look, let me put it another way. Don't you see that the
very falsity of each of the statements that you assert saves you from an
erroneous belief in the preceding one? The first statement is, as I told
you, false. Very well! Now the second statement is simply to the effect that
you believe the first statement. If the second statement were true, then you
would believe the first statement, and hence your belief about the first
statement would indeed be in error. But fortunately the second statement is
false, hence you don't really believe the first statement, so your belief in
the first statement is not in error. Thus the falsity of the second
statement implies you do not have an erroneous belief about the first; the
falsity of the third likewise saves you from an erroneous belief about the
second, etc.
FRANK: Now I see perfectly! So none of my beliefs were erroneous, only
the statements were erroneous.
EPISTEMOLOGIST: Exactly.
FRANK: Most remarkable! Incidentally, what color is the book really?
EPISTEMOLOGIST: It is red.
FRANK: What!
EPISTEMOLOGIST: Exactly! Of course the book is red. What's the matter
with you, don't you have eyes?
FRANK: But didn't I in effect keep saying that the book is red all
along?
EPISTEMOLOGIST: Of course not! You kept saying it seems red to you, it
seems like it seems red to you, you believe it is red, you believe that you
believe it is red, and so forth. Not once did you say that it is red. When I
originally asked you "What color is the book?" if you had simply answered
"red," this whole painful discussion would have been avoided.
Scene 3. Frank comes back several months later to the home of the
epistemologist.
EPISTEMOLOGIST: How delightful to see you! Please sit down.
FRANK (seated): I have been thinking of our last discussion, and there
is much I wish to clear up. To begin with, I discovered an inconsistency in
some of the things you said.
EPISTEMOLOGIST: Delightful! I love inconsistencies. Pray tell!
FRANK: Well, you claimed that although my belief sentences were false,
I did not have any actual beliefs that are false. If you had not admitted
that the book actually is red, you would have been consistent. But your very
admission that the book is red, leads to an inconsistency.
EPISTEMOLOGIST: How so?
FRANK: Look, as you correctly pointed out, in each of my belief
sentences "I believe it is red," "I believe that I believe it is red," the
falsity of each one other than the first saves me from an erroneous belief
in the proceeding one. However, you neglected to take into consideration the
first sentence itself. The falsity of the first sentence "I believe it is
red," in conjunction with the fact that it is red, does imply that I do have
a false belief.
EPISTEMOLOGIST: I don't see why.
FRANK: It is obvious! Since the sentence "I believe it is red" is
false, then I in fact believe it is not red, and since it really is red,
then I do have a false belief. So there!
EPISTEMOLOGIST (disappointed): I am sorry, but your proof obviously
fails. Of course the falsity of the fact that you believe it is red implies
that you don't believe it is red. But this does not mean that you believe it
is not red!
FRANK: But obviously I know that it either is red or it isn't, so if I
don't believe it is, then I must believe that it isn't.
EPISTEMOLOGIST: Not at all. I believe that either Jupiter has life or
it doesn't. But I neither believe that it does, nor do I believe that it
doesn't. I have no evidence one way or the other.
FRANK: Oh well, I guess you are right. But let us come to more
important matters. I honestly find it impossible that I can be in error
concerning my own beliefs.
EPISTEMOLOGIST: Must we go through this again? I have already patiently
explained to you that you (in the sense of your beliefs, not your
statements) are not in error.
FRANK: Oh, all right then, I simply do not believe that even the
statements are in error. Yes, according to the machine they are in error,
but why should I trust the machine?
EPISTEMOLOGIST: Whoever said you should trust the machine?
FRANK: Well, should I trust the machine?
EPISTEMOLOGIST: That question involving the word "should" is out of my
domain. However, if you like, I can refer you to a colleague who is an
excellent moralist--he may be able to answer this for you.
FRANK: Oh come on now, I obviously didn't mean "should" in a moralistic
sense. I simply meant "Do I have any evidence that this machine is
reliable?"
EPISTEMOLOGIST: Well, do you?
FRANK: Don't ask me! What I mean is should you trust the machine?
EPISTEMOLOGIST: Should I trust it? I have no idea, and I couldn't care
less what I should do.
FRANK: Oh, your moralistic hangup again. I mean, do you have evidence
that the machine is reliable?
EPISTEMOLOGIST: Well of course!
FRANK: Then let's get down to brass tacks. What is your evidence?
EPISTEMOLOGIST: You hardly can expect that I can answer this for you in
an hour, a day, or a week. If you wish to study this machine with me, we can
do so, but I assure you this is a matter of several years. At the end of
that time, however, you would certainly not have the slightest doubts about
the reliability of the machine.
FRANK: Well, possibly I could believe that it is reliable in the sense
that its measurements are accurate, but then I would doubt that what it
actually measures is very significant. It seems that all it measures is
one's physiological states and activities.
EPISTEMOLOGIST: But of course, what else would you expect it to
measure?
FRANK: I doubt that it measures my psychological states, my actual
beliefs.
EPISTEMOLOGIST: Are we back to that again? The machine does measure
those physiological states and processes that you call psychological states,
beliefs, sensations, and so forth.
FRANK: At this point I am becoming convinced that our entire difference
is purely semantical. All right, I will grant that your machine does
correctly measure beliefs in your sense of the word "belief," but I don't
believe that it has any possibility of measuring beliefs in my sense of the
word "believe." In other words I claim that our entire deadlock is simply
due to the fact that you and I mean different things by the word "belief."
EPISTEMOLOGIST: Fortunately, the correctness of your claim can be
decided experimentally. It so happens that I now have two brain-reading
machines in my office, so I now direct one to your brain to find out what
you mean by "believe" and now I direct the other to my own brain to find out
what I mean by "believe," and now I shall compare the two readings. Nope,
I'm sorry, but it turns out that we mean exactly the same thing by the word
"believe."
FRANK: Oh, hang your machine! Do you believe we mean the same thing by
the word "believe"?
EPISTEMOLOGIST: Do I believe it? Just a moment while I check with the
machine. Yes, it turns out I do believe it.
FRANK: My goodness, do you mean to say that you can't even tell me what
you believe without consulting the machine?
EPISTEMOLOGIST: Of course not.
FRANK: But most people when asked what they believe simply tell you.
Why do you, in order to find out your beliefs, go through the fantastically
roundabout process of directing a thought-reading machine to your own brain
and then finding out what you believe on the basis of the machine readings?
EPISTEMOLOGIST: What other scientific, objective way is there of
finding out what I believe?
FRANK: Oh, come now, why don't you just ask yourself?
EPISTEMOLOGIST (sadly): It doesn't work. Whenever I ask myself what I
believe, I never get any answer!
FRANK: Well, why don't you just state what you believe?
EPISTEMOLOGIST: How can I state what I believe before I know what I
believe?
FRANK: Oh, to hell with your knowledge of what you believe; surely you
have some idea or belief as to what you believe, don't you?
EPISTEMOLOGIST: oOf course I have such a belief. But how do I find out
what this belief is?
FRANK: I am afraid we are getting into another infinite regress. Look,
at this point I am honestly beginning to wonder whether you may be going
crazy.
EPISTEMOLOGIST: Let me consult the machine. Yes, it turns out that I
may be going crazy.
FRANK: Good God, man, doesn't this frighten you?
EPISTEMOLOGIST: Let me check! Yes, it turns out that it does frighten
me.
FRANK: Oh please, can't you forget this damned machine and just tell me
whether you are frightened or not?
EPISTEMOLOGIST: I just told you that I am. However, I only learned of
this from the machine.
FRANK: I can see that it is utterly hopeless to wean you away from the
machine. Very well, then, let us play along with the machine some more. Why
don't you ask the machine whether your sanity can be saved?
EPISTEMOLOGIST: Good idea! Yes, it turns out that it can be saved.
FRANK: And how can it be saved?
EPISTEMOLOGIST: I don't know, I haven't asked the machine.
FRANK: Well, for God's sake, ask it!
EPISTEMOLOGIST: Good idea. It turns out that...
FRANK: It turns out what?
EPISTEMOLOGIST: It turns out that...
FRANK: Come on now, it turns out what?
EPISTEMOLOGIST: This is the most fantastic thing I have ever come
across! According to the machine the best thing I can do is to cease to
trust the machine!
FRANK: Good! What will you do about it?
EPISTEMOLOGIST: How do I know what I will do about it, I can't read the
future?
FRANK: I mean, what do you presently intend to do about it?
EPISTEMOLOGIST: Good question, let me consult the machine. According to
the machine, my current intentions are in complete conflict. And I can see
why! I am caught in a terrible paradox! If the machine is trustworthy, then
I had better accept its suggestion to distrust it. But if I distrust it,
then I also distrust its suggestion to distrust it, so I am really in a
total quandary.
FRANK: Look, I know of someone who I think might be really of help in
this problem. I'll leave you for a while to consult him. Au revoir!
Scene 4. (Later in the day at a psychiatrist's office.)
FRANK: Doctor, I am terribly worried about a friend of mine. He calls
himself an "experimental epistemologist."
DOCTOR: Oh, the experimental epistemologist. There is only one in the
world. I know him well!
FRANK: That is a relief. But do you realize that he has constructed a
mind-reading device that he now directs to his own brain, and whenever one
asks him what he thinks, believes, feels, is afraid of, and so on, he has to
consult the machine first before answering? Don't you think this is pretty
serious?
DOCTOR: Not as serious as it might seem. My prognosis for him is
actually quite good.
FRANK: Well, if you are a friend of his, couldn't you sort of keep an
eye on him?
DOCTOR: I do see him quite frequently, and I do observe him much.
However, I don't think he can be helped by so-called "psychiatric
treatment." His problem is an unusual one, the sort that has to work itself
out. And I believe it will.
FRANK: Well, I hope your optimism is justified. At any rate I sure
think I need some help at this point!
DOCTOR: How so?
FRANK: My experiences with the epistemologist have been thoroughly
unnerving! At this point I wonder if I may be going crazy; I can't even have
confidence in how things appear to me. I think maybe you could be helpful
here.
DOCTOR: I would be happy to but cannot for a while. For the next three
months I am unbelievably overloaded with work. After that, unfortunately, I
must go on a three-month vacation. So in six months come back and we can
talk this over.
Scene 5. (Same office, six months later.)
DOCTOR: Before we go into your problems, you will be happy to hear that
your friend the epistemologist is now completely recovered.
FRANK: Marvelous, how did it happen?
DOCTOR: Almost, as it were, by a stroke of fate--and yet his very
mental activities were, so to speak, part of the "fate." What happened was
this: For months after you last saw him, he went around worrying "should I
trust the machine, shouldn't I trust the machine, should I, shouldn't I,
should I, shouldn't I." (He decided to use the word "should" in your
empirical sense.) He got nowhere! So he then decided to "formalize" the
whole argument. He reviewed his study of symbolic logic, took the axioms of
first-order logic, and added as nonlogical axioms certain relevant facts
about the machine. Of course the resulting system was inconsistent--he
formally proved that he should trust the machine if and only if he
shouldn't, and hence that he both should and should not trust the machine.
Now, as you may know, in a system based on classical logic (which is the
logic he used), if one can prove so much as a single contradictory
proposition, then one can prove any proposition, hence the whole system
breaks down. So he decided to use a logic weaker than classical logic--a
logic close to what is known as "minimal logic"--in which the proof of one
contradiction does not necessarily entail the proof of every proposition.
However, this system turned out too weak to decide the question of whether
or not he should trust the machine. Then he had the following bright idea.
Why not use classical logic in his system even though the resulting system
is inconsistent? Is an inconsistent system necessarily useless? Not at all!
Even though given any proposition, there exists a proof that it is true and
another proof that it is false, it may be the case that for any such pair of
proofs, one of them is simply more psychologically convincing than the
other, so simply pick the proof you actually believe! Theoretically the idea
turned out very well--the actual system he obtained really did have the
property that given any such pair of proofs, one of them was always
psychologically far more convincing than the other. Better yet, given any
pair of contradictory propositions, all proofs of one were more convincing
than any proof of the other. Indeed, anyone except the epistemologist could
have used the system to decide whether the machine could be trusted. But
with the epistemologist, what happened was this: He obtained one proof that
he should trust the machine and another proof that he should not. Which
proof was more convincing to him, which proof did he really "believe"? The
only way he could find out was to consult the machine! But he realized that
this would be begging the question, since his consulting the machine would
be a tacit admission that he did in fact trust the machine. So he still
remained in a quandary.
FRANK: So how did he get out of it?
DOCTOR: Well, here is where fate kindly interceded. Due to his absolute
absorption in the theory of this problem, which consumed about his every
waking hour, he became for the first time in his life experimentally
negligent. As a result, quite unknown to him, a few minor units of his
machine blew out! Then, for the first time, the machine started giving
contradictory information--not merely subtle paradoxes, but blatant
contradictions. In particular, the machine one day claimed that the
epistemologist believed a certain proposition and a few days later claimed
he did not believe that proposition. And to add insult to injury, the
machine claimed that he had not changed his belief in the last few days.
This was enough to simply make him totally distrust the machine. Now he is
fit as a fiddle.
FRANK: This is certainly the most amazing thing I have ever heard! I
guess the machine was really dangerous and unreliable all along.
DOCTOR: Oh, not at all; the machine used to be excellent before the
epistemologist's experimental carelessness put it out of whack.
FRANK: Well, surely when I knew it, it couldn't have been very
reliable.
DOCTOR: Not so, Frank, and this brings us to your problem. I know about
your entire conversation with the epistemologist--it was all tape-recorded.
FRANK: Then surely you realize the machine could not have been right
when it denied that I believed the book was red.
DOCTOR: Why not?
FRANK: Good God, do I have to go through all this nightmare again? I
can understand that a person can be wrong if he claims that a certain
physical object has a certain property, but have you ever known a single
case when a person can be mistaken when he claims to have or not have a
certain sensation?
DOCTOR: Why, certainly! I once knew a Christian Scientist who had a
raging toothache; he was frantically groaning and moaning all over the
place. When asked whether a dentist might not cure him, he replied that
there was nothing to be cured. Then he was asked, "But do you not feel
pain?" He replied, "No, I do not feel pain; nobody feels pain, there is no
such thing as pain, pain is only an illusion." So here is a case of a man
who claimed not to feel pain, yet everyone present knew perfectly well that
he did feel pain. I certainly don't believe he was lying, he was just simply
mistaken.
FRANK: Well, all right, in a case like that. But how can one be
mistaken if one asserts his belief about the color of a book?
DOCTOR: I can assure you that without access to any machine, if I asked
someone what color is this book, and he answered, "I believe it is red," I
would be very doubtful that he really believed it. It seems to me that if he
really believed it, he would answer, "It is red" and not "I believe it is
red" or "It seems red to me." The very timidity of his response would be
indicative of his doubts.
FRANK: But why on earth should I have doubted that it was red?
DOCTOR: You should know that better than I. Let us see now, have you
ever in the past had reason to doubt the accuracy of your sense perception?
FRANK: Why, yes. A few weeks before visiting the epistemologist, I
suffered from an eye disease, which did make me see colors falsely. But I
was cured before my visit.
DOCTOR: Oh, so no wonder you doubted it was red! True enough, your eyes
perceived the correct color of the book, but your earlier experience
lingered in your mind and made it impossible for you to really believe it
was red. So the machine was right!
FRANK: Well, all right, but then why did I doubt that I believed it was
true?
DOCTOR: Because you didn't believe it was true, and unconsciously you
were smart enough to realize the fact. Besides, when one starts doubting
one's own sense perceptions, the doubt spreads like an infection to higher
and higher levels of abstraction until finally the whole belief system
becomes one doubting mass of insecurity. I bet that if you went to the
epistemologist's office now, and if the machine were repaired, and you now
claimed that you believe the book is red, the machine would concur.
No, Frank, the machine is--or, rather, was--a good one. The
epistemologist learned much from it, but misused it when he applied it to
his own brain. He really should have known better than to create such an
unstable situation. The combination of his brain and the machine each
scrutinizing and influencing the behavior of the other led to serious
problems in feedback. Finally the whole system went into a cybernetic
wobble. Something was bound to give sooner or later. Fortunately, it was the
machine.
FRANK: I see. One last question, though. How could the machine be
trustworthy when it claimed to be untrustworthy?
DOCTOR: The machine never claimed to be untrustworthy, it only claimed
that the epistemologist would be better off not trusting it. And the machine
was right.
--------
If Smullyan's nightmare strikes you as too outlandish to be convincing,
consider a more realistic fable--not a true story, but surely possible:
Once upon a time there were two coffee tasters, Mr. Chase and Mr.
Sanborn, who worked for Maxwell House. Along with half a dozen other coffee
tasters, their job was to ensure that the taste of Maxwell House stayed
constant, year after year. One day, about six years after Mr. Chase had come
to work for Maxwell House, he cleared his throat and confessed to Mr.
Sanborn:
"You know, I hate to admit it, but I'm not enjoying this work any more.
When I came to Maxwell House six years ago, I thought Maxwell House coffee
was the best-tasting coffee in the world. I was proud to have a share in the
responsibility for preserving that flavor over the years. And we've done our
job well; the coffee tastes today just the way it tasted when I arrived.
But, you know, I no longer like it! My tastes have changed. I've become a
more sophisticated coffee drinker. I no longer like that taste at all."
Sanborn greeted this revelation with considerable interest. "It's funny
you should mention it," he replied, "for something rather similar has
happened to me. When I arrived here, shortly before you did, I, like you,
thought Maxwell House coffee was tops in flavor. And now I, like you, really
don't care for the coffee we're making. But my tastes haven't changed; my...
tasters have changed. That is, I think something has gone wrong with my
taste buds or something--you know, the way your taste buds go off when you
take a bite of pancakes and maple syrup and then go back to your orange
juice? Maxwell House coffee doesn't taste to me the way it used to taste; if
only it did, I'd still love it, for I still think that taste is the best
taste in coffee. Now, I'm not saying we haven't done our job well. You other
guys all agree that the taste is the same, so it must be my problem alone. I
guess I'm no longer cut out for this work."
Chase and Sanborn are alike in one way. Both used to like Maxwell House
coffee; now neither one likes it. But they claim to be different in another
way: Maxwell House tastes to Chase the way it always did, but not so for
Sanborn. The difference seems familiar and striking, yet when they confront
each other, they may begin to wonder if their cases arc really all that
different. "Could it be," Chase might wonder, "that Mr. Sanborn is really in
my predicament and just hasn't noticed the gradual rise in his standards and
sophistication as a coffee taster?" "Could it be," Sanborn might wonder,
"that Mr. Chase is kidding himself when he says the coffee tastes just the
same to him as it used to?"
Do you remember your first sip of beer? Terrible! How could anyone like
that stuff? But beer, you reflect, is an acquired taste; one gradually
trains oneself--or just comes--to enjoy that flavor. What flavor? The flavor
of that first sip? No one could like that flavor! Beer tastes different to
the experienced beer drinker. Then beer isn't an acquired taste; one doesn't
learn to like that first taste; one gradually comes to experience a
different, and likable, taste. Had the first sip tasted that way, you would
have liked beer wholeheartedly from the beginning!
Perhaps, then, there is no separating the taste from the response to
the taste, the judgment of good or bad. Then Chase and Sanborn might be just
alike, and simply be choosing slightly different ways of expressing
themselves. But if they were just alike, then they'd actually both be wrong
about something, for they each have sincerely denied that they are like the
other. Is it conceivable that each could have inadvertently misdescribed his
own case and described the other's instead? Perhaps Chase is the one whose
taste buds have changed, while Sanborn is the sophisticate. Could they be
that wrong?
Some philosophers--and other people--have thought that a person simply
cannot be wrong about such a matter. Everyone is the final and unimpeachable
arbiter of how it is with him; if Chase and Sanborn have spoken sincerely,
and have made no unnoticed slips of language, and if both know the meanings
of their words, they must have expressed the truth in each case. Can't we
imagine tests that would tend to confirm their different tales? If Sanborn
does poorly on discrimination tests he used to pass with flying colors, and
if, moreover, we find abnormalities in his taste buds (it's all that
Szechuan food he's been eating lately, we discover), this will tend to
confirm his view of his situation. And if Chase passes all those tests
better than he used to, and exhibits increased knowledge of coffee types and
a great interest in their relative merits and peculiar characteristics, this
will support his view of himself. But if such tests could support Chase s
and Sanborn's authority, failing them would have to undermine their
authority. If Chase passed Sanborn's tests and Sanborn passed Chase's, each
would have doubt cast on his account--if such tests have any bearing at all
on the issue.
Another way of putting the point is that the price you pay for the
possibility of confirming your authority is the outside chance of being
discredited. "I know what I like," we are all prepared to insist, "and I
know what it's like to be me!" Probably you do, at least about some matters,
but that is something to be checked in performance. Maybe, just maybe,
you'll discover that you really don't know as much as you thought you did
about what it is like to be you.