Five Thousand B.C. and Other Philosophical Fantasies

by Raymond Smullyan

  At any rate, I no longer believe in any absolute notion of what is real. I only think of the reality of a state or of an object as relative to some other state. Thus, the very question of whether I am now dreaming in some absolute sense is (to me) meaningless. I can only consider such a purely empirical question as whether or not my present state will one day seem unreal. Every state is real relative to itself. To me, it is an open question whether or not every state may be unreal relative to some other state.2

  SKEPTIC: I must say, your idea terrifies me! Look, before we started talking about dreams, I thought that the whole time you were defending the philosophy of common sense in an uninhibitedly dogmatic manner. You see chairs; therefore, there are chairs, and so forth. Then you pull this complete reversal and come up with this ultrafantastic idealism! I must say, I am completely bewildered, and it will take me awhile to get over the shock.

  SUBJECT: I don’t regard this idea as either fantastic or idealistic.

  SKEPTIC: Of course it is idealistic to say that nothing has absolute reality, that reality is only relative to something else!

  SUBJECT: This is not idealism.

  SKEPTIC: Look, I’m not going to quibble with you over terminology. Maybe it shouldn’t be called idealism but simply crazy and fantastic. All right, I admit that on purely logical grounds, your position is no more disprovable than, say, something like solipsism. At least, at the moment I am not clever enough to find an actual inconsistency in your doctrine. So on rational grounds, I cannot refute you. But on psychological grounds I find the doctrine extremely dangerous. Frankly, the idea that one day I might wake up or be in another state relative to which all the objects and people around me that I have come to know and love should turn out to be unreal fills me with utter horror and totally shatters my feelings of security.

  SUBJECT: I am glad that you brought up psychological factors because I think that they are most relevant. My psychological reaction is the very opposite of yours; to me, the belief in some absolute reality would make me highly insecure!

  SKEPTIC: Why on earth should it do that?

  SUBJECT: Because once I believed in this thing called reality, then I would start worrying about whether the things that appeared real to me really were real!

  SKEPTIC: Why can’t you just know that they are real as I do?

  SUBJECT: Hey, I thought you were the skeptic! It seems in some ways that I am more skeptical than you.

  SKEPTIC: You sure are! Indeed, your whole method of philosophizing is the strangest mixture of dogmatism and skepticism I have ever seen! About certain things you are totally dogmatic and about all other things—all things that are not your dogmas—you are skeptical.

  SUBJECT: But of course! How could I be anything other than dogmatic about things that I know and skeptical about things that I don’t?

  SKEPTIC: But tell me honestly, why are you skeptical that the things before you are real in any absolute sense?

  SUBJECT: When you use the word why, I am not sure whether you are asking for a psychological explanation as to how I got this way, or whether you are asking for my epistemological reasons. Let me first consider the former, which brings us back to the very important point you raised about feeling secure. Don’t you see that once I admitted an absolute reality, I would have all the nightmarish problems about whether I am really awake or not. But without this category, all these awful problems don’t even arise!

  SKEPTIC: But ignoring a problem does not solve it! I can’t reject the notion of reality just to avoid facing problems. Besides, the very thought that there is no such thing as reality itself makes me insecure.

  SUBJECT: Originally, you told me that my philosophy, though possibly consistent, was dangerous because it leads to psychological insecurity. In other words, your immediate reason for rejecting it was that it makes you feel insecure. But now when I tell you that it makes me feel secure, you say these are not legitimate grounds for accepting it. Are you being quite fair?

  SKEPTIC: No, you are right.

  SUBJECT: I would like to say more about feeling secure. It is difficult for me to believe that what really makes you (or me, for that matter) feel insecure is that the objects we both see lack this property of absolute reality. Isn’t the real fear that at some future time we may come to believe or to feel the unreality of the objects we both now perceive?

  SKEPTIC: That is certainly part of it, but not all.

  SUBJECT: Well, let me put it this way. Suppose God himself (or any being you would take to be both omniscient and truthful) would now come down to earth and say to you, “There is indeed such a thing as absolute reality. But, for certain reasons, I am not going to tell you whether any of the things or people you now perceive are real. This much I promise you, however: Never will you have the experience of one day being in a state relative to which your present state will appear like a dream. In other words, if you are dreaming now, then—unlike the dreams you have had before—you will never know it, not even in the afterlife, if there is one.” My question now is whether this answer would satisfy you.

  SKEPTIC: I’m afraid not. This would mean that I never would know which things were real and which were not.

  SUBJECT: Well, suppose God then said, “All right, I’ll tell you after all. Everything you now see is real.” Would that satisfy you?

  SKEPTIC: It would still not satisfy me, because I might be afraid that I was only dreaming that God spoke to me.

  SUBJECT: Hey, it seems that you are the one who is really insecure! Insecure, that is, in your philosophy, not mine!

  SKEPTIC: I’m afraid you are right Well, I guess what I need is to have faith that I am now not dreaming.

  SUBJECT: Ah! That is precisely the difference between your approach and mine. I don’t want my feeling of security to have to depend on any act of faith. I have always thought of faith as somehow “whistling in the dark.”

  SKEPTIC: But how without some act of faith can you know you are not now dreaming?

  SUBJECT: I told you before that I use the word dream only in a relative sense. But a point that I think may be important has just occurred to me. When I suggest the possibility that reality is only relative, that every world (or state) may be unreal relative to some other world, does this idea make you feel that the present world (the one we are now in and see) is less real than you would normally feel, or that other worlds are more real? In other words, do you feel that I am trying to make the present world more fantasylike, dreamlike, or chimerical or that I am trying to make fantasy worlds appear more real?

  SKEPTIC: Why, the former, of course. If I believed that every world was unreal relative to some other world, then I would feel that all worlds, including this one, were unreal.

  SUBJECT: Oh, if that is your reaction, then I certainly don’t blame you for totally rejecting the idea. I was thinking of it the opposite way! I was not trying to “derealify” this world but rather to “realify” so-called nonreal worlds. Why can’t you see it in this light?

  SKEPTIC: I don’t know; the idea is quite new to me. I would have to think about it.

  SUBJECT: You see, there is one important difference in our attitudes. Suppose for the moment that there really is an afterlife and that in the first state we enter the present world is unreal relative to that state. Your reaction will be very different from mine. You will say, “How surprising; I thought my previous state was real, but I was wrong; I was deceived.” I will say, “Just as I thought, the last state was real and interesting while it lasted, but was impermanent. Too bad, I guess nothing lasts forever.”

  I really think that the notion of permanence is the key to the whole business. Let me ask you another question. Suppose you were on another planet—call it Planet A—on which all the inhabitants, including yourself, slept half the time (instead of roughly a third of the time, as we do here). Now suppose at the end of each day on Planet A you undressed, went to bed, fell asleep, and found yourself in a totally different body—call it Body B—on a totally diff
erent planet called Planet B. You would spend a day on Planet B, at the end of which your B-body would undress, get into bed, go to sleep, and then you would return to State A. Let us assume that your existence in State B were just as consistent and coherent as in State A. When in State A you put some object on the desk and went to sleep, the next morning it was still there, and the same held for State B. Assume also that this state of affairs has been going on all your life; indeed, you were unable to recall whether your life started in State A or State B. I repeat, each state had the same coherent internal structure. Let us say that science and psychology were about equally advanced in both worlds. The scientists of World A would assure you that your thought processes were nothing more nor less than certain physiological events in your brain—call it Brain A. They would tell you that when you went to sleep and “dreamed” you were on Planet B, this “dream” was nothing more than certain physical events taking place in Brain A. But the scientists of Planet B would tell you exactly the same thing in reverse; all your thoughts were nothing but events in Brain B. Moreover, they would tell you that Brain A doesn’t really exist at all; those on Planet A would tell you that Brain B doesn’t really exist except as a figment of the imagination of Brain A. I can even imagine the psychiatrists of both planets each diagnosing you as schizophrenic for believing in the reality of the other state; perhaps each would offer you some medication that would permanently cure you of your “illusion” concerning the other state.

  Now, you must admit that under these circumstances your whole notion of reality would probably be very different. What would you believe? That either State A or State B was real and the other illusory, but you couldn’t decide which? Or maybe that both states were real—that there could be, so to speak, two disjoint realities? Or perhaps you would suspect that both states were unreal and that your real state—State C—was something very different yet? Or maybe that no states are real? Don’t you think that you would reject the very notion of reality as meaningless and would simply settle for the realization that each of the two states was internally real but that neither one was real relative to the other and that the only common bond would be that you experience them both?

  SKEPTIC: Of course, had I lived such a life, my views on reality would probably have been very different. But the fact is that I have not lived such a weird life. So why should I let my views be influenced by the hypothetical situation you have just been spinning out, which itself is just a sheer fantasy? I’d like to know what you are really driving at. Tell me honestly, why arc you so intent on trying to relativize the notion of reality? You said before something about having some epistemological reasons for rejecting any absolute notion of reality. What now are these reasons?

  SUBJECT: My reason for rejecting it is very simply that I have absolutely no reasons for accepting it. Indeed, I don’t even know what the notion really means! I have no idea how I can use the notion. Suppose I enter a new place and see a wooden chair. At least it looks wooden to me, but then it occurs to me that it may not be really wooden; perhaps it is cleverly painted papier mache. In this sense, the word really means something quite definite to me; I know how to go about testing it. So I go over to the chair, inspect it more closely, feel it, and so forth, and conclude, “Yes, it really is made of wood.” But now, what in the world would it mean for me to ask, “But is this chair real, or is it only illusory?” What test can I possibly perform to find out if the chair has this mysterious property of being real?

  SKEPTIC: Why is it that you, who are usually so hostile to positivism, take such a positivist attitude toward this question?

  SUBJECT: Because in this regard, I feel that the positivists have something of value to contribute. Incidentally, concerning my “hostile” attitude toward positivism, I think that I should state clearly that I divide positivists into two types, which I call dogmatic positivists and skeptical positivists. The dogmatic positivist will say about any word, phrase, or sentence whose meaning he cannot understand that it is meaningless or nonsensical. The skeptical positivist will instead be skeptical that it has any meaning or will wonder what the meaning could be. I am perfectly sympathetic to the skeptical positivist; it is only the dogmatic positivist of whom I am totally intolerant. After all, since I am dogmatic myself, it is only natural that I cannot tolerate any dogmas that conflict with mine.

  But coming back to the notion of absolute reality, I, like the skeptical positivist, do not really understand what the notion is and indeed have some doubts that the notion has any real meaning. But I am not prepared to say that it is meaningless. The notion of absolute reality somehow reminds me of the notion of absolute position in space or absolute motion in space. When people first hear from the physical relativist that there is no such thing as bodies moving through something called space, but that bodies move only relative to each other, the reaction is often something of a shock; the new idea somehow seems counterintuitive. The dogmatic type of relativist will say, “There is no such thing as absolute motion; this is just an antiquated notion.” The more modest and reasonable type of relativist, when asked, “How do you know that there is no such thing as absolute motion through space?” will reply, “I cannot say for sure that there is no such thing but merely that I do not know what it is and can see no possible way to use it in science. The subject matter of physical science is simply the description of how objects move relative to each other. And nowhere can I see how the hypothesis of absolute motion can be used in this study.”

  I have similar feelings about a chair’s being real. Saying that it is relatively real is quite different. Again, this notion is related to the notion of permanence. I will put it this way: I certainly do have a notion of something appearing real or seeming real to me. For example, the chair I see before me certainly seems real to me. The chair I saw yesterday while I was awake seemed real to me then and still seems real to me in retrospect. But the objects I saw last night in my sleep seemed real to me then (at least as far as I now remember) but do not seem real to me now. So it is perfectly meaningful to ask whether I may in the future be in a state in which the chair I presently perceive will then seem unreal to me.

  SKEPTIC: But this again is something you cannot now test.

  SUBJECT: Of course I can’t possibly test the chair to find out whether in the future it will seem real to me any more than I can now test it to determine whether in the future some rock will be hurled through the window and demolish it.3 But both notions seem to me perfectly meaningful.

  SKEPTIC: Perhaps your idea of relative reality is not so bad after all. It also may not be a bad idea to define something to be absolutely real to a given observer if it is in your sense permanently real, that is, if at no future time will it seem unreal.

  Still, I am vaguely disquieted. I must say that I have a lingering intuition that there is something more to reality than a mere reduction to a permanent set of appearances. Do you honestly maintain that you have no such intuition?

  SUBJECT: To be absolutely honest, I do have such a lingering intuition. But for that matter, I must also confess that I still have left some remnants of my childhood intuition concerning absolute motion.

  SKEPTIC: So how do you reconcile these intuitions with your relativist position?

  SUBJECT: I, as it were, hold such intuitions in abeyance. Incidentally, my intuition concerning absolute motion is much weaker than my intuition concerning absolute reality. Indeed, by now it has practically disappeared. But with the notion of absolute reality I am less sure that there is nothing to it. What should one do with such intuitions, intuitions that conflict with reason or with stronger intuitions? I do not believe in being overly brutal and harsh—even with oneself—and tearing out those intuitions that one regretfully realizes are not in complete harmony with one’s general world view. I have far too much respect for any intuition to wish to “murder” it. So I let such intuitions, so to speak, lie asleep. I say to myself, “It is difficult to know what absolute reality can be, other than what
I have suggested. But then again it appears possibly to have some other meaning. But I don’t know how to work with such a meaning. So I will suspend final judgment until I have more knowledge.”

  SKEPTIC: I think your attitude is very reasonable. Still, I would love to know just a little more about your intuition of absolute reality. Strange, isn’t it, that I have been defending this notion, and you have been attacking it. Yet you have so convinced me that this notion is unsatisfactory that I have to appeal to you for help in finding out what I mean by absolutely real! What is it you are looking for, and how will you recognize it if you ever find out? Or do you feel that in principle you never can?

  SUBJECT: No, I would not say that in principle I never can find it, though I have as yet no idea of how I can or even just what it is that I seek. I am not one to go along with the idea that it is hopeless to find something unless one knows precisely what it is that one is looking for. So it is with the notion of absolute reality. I told you all my skeptical reasons for doubting that there is really anything to this notion, and so I am unable to use it in my actual life. Yet, as I have confessed, I still sometimes have the haunting feeling that I am overlooking something crucial, that I may be missing something of extreme importance. How can I find it? God only knows! There is nothing more at present that I can possibly do. But who knows? Maybe one day the idea, if there really is any idea, might dawn on me. Perhaps through further advance of science, through a more refined logical analysis of the question, or through something like a sudden mystical insight, it might happily happen that I will say, “Ah, of course! How simple! So that’s what reality really is!”