PHILONOUS    Greetings, dear friend. What are you pondering about so lonely in this beautiful park?
HYLAS    Ah, that is you? I am glad to see you. Last night I worked hard to develop an idea which promises infinitely much to mankind.
PHILONOUS    What kind of precious idea is that?
HYLAS    I arrived at the conviction (which actually is certainty) that people will some time achieve immortality.
PHILONOUS    Do I get this right? How is that, you are not unfaithful to materialism which you have hitherto lectured on, do you?
HYLAS    Never. My idea does not collide with materialism, on the contrary, it necessarily follows from it.
PHILONOUS    I am all ears. Do explain, my friend.
HYLAS    As you know, nothing exists beyond matter. These clouds, these autumn trees, this pale yellow sun, we finally - these are all material objects, that is, collections of atoms; the various properties of the objects, however, are due to the difference in their atomic structures. Because those are the same oxygen, carbon, or iron atoms, whether they are in stones, leaves, or in our blood. Those formations differ solely by their construction, by the different positions of their particles, that is, by their structure. Therefore one can say quite generally that there are only atoms and their structures. Hence I posed myself the question what is the reason that I still feel to be the same Hylas which used to play here as a little boy, despite all the years which passed in the meantime. Is this feeling of individual identity - I am asking myself - caused by the identity of the building material of my body, i.e., the atoms of which it is composed? But it cannot be like this. For we know through science that the atoms of our bodies are constantly replaced owing to the meals and drinks that we take and the air that we breathe. Bone, nerve, and skin cells continuously exchange their atoms so fast that after a couple of weeks all material particles which made up my organism can be found floating in the waves of a river or in a cloud; nonetheless I continue to exist and I feel the continuity of my personality. What is this due to? Surely not my unchanged atomic structure. Just take into consideration that the new atoms of my body are not the same which were there a month ago, they are, however, of the same kind, and that is quite enough. Thus I posit: The identity of my existence depends on the identity of my structure.
PHILONOUS    Agreed. And then?
HYLAS    In the future people will make better and increasingly true copies of the atomic structures of all material products of the Creation. Today already they are able to produce artificial diamonds or sapphires, artificial urea and even artificial, synthetic protein. Some day they will undoubtedly master the art of building, first, the molecules of the living body, then the body itself - from atoms. In this moment they achieved immortality, because they will be able to bring back to life every deceased, through perfect arrangement of atoms according to the structure which his body showed in his lifetime. This process of resurrection will take place - as I see it - in a machine which is fed with the appropriate scheme, a kind of a building plan, i.e., the structural formula of a particular human according to which the machine makes protein molecules, cells, tendons, nerves from atoms - and then this human leaves the machine, bright and cheery and perfectly healthy. Now, what do you think about it?
PHILONOUS    I say that one has to discuss the problem from all sides.
HYLAS    Is there anything else to discuss? We are not able to build such a machine yet, but the progress of science makes us certain that it will be built some time, and it is not important to us philosophers if this will happen in thousand or a million years. As I said before, there is nothing in nature beyond atoms and their structures. In particular, there is no immortal soul which, leaving the dead, will waft away to the kingdom come. Consequently, someone mastering the art of rearranging the atoms of bodies long decayed according to their structure will be able, eo ipso, to recall these bodies to life with their original shape and functions. But he who has reconstructed the body of a deceased person from atoms - will cause his presence in the prime of his life, although that person had been borne to his grave centuries ago ...
PHILONOUS    You think so? Excellent. Do you mind me asking a few questions in order to investigate the specifics of your machine which recalls to life from atoms, and would you give me some answers?
HYLAS    I do happily agree.
PHILONOUS    Great. Imagine, Hylas, that you have to die today, because you are in power of a tyrant who has taken the irrevocable decision to kill you, and who has all possible means to do so. The time of your execution is seven o'clock in the morning. At six, i.e., right now, you go for your last walk before death, tortured by sorrow and fear, and you meet me and tell me about your misfortune.
Are you ready to take this starting point for our disputation of this fictitious situation, in which you are sentenced to death, whereas I am - your friend, willing to help you, being at the same time the inventor of the machine which can resurrect from atoms?
HYLAS    I am ready. Speak.
PHILONOUS    My poor Hylas, you have to die, oh dear, that is terrible! But you are a materialist, aren't you?
HYLAS    That is true.
PHILONOUS    That is very convenient. I have just finished the construction of that machine about which we have talked so much recently. The copies which I make by it's means are indistinguishable from the originals. Not only are the mortal remains of  the human which is composed from atoms by my machine identical to those of the original, he has, furthermore, all mental properties of the latter; to give an example, I just want to mention the memory - as you know, it is based on certain individual features of the brain structure. My machine delivers a copy of the structure of the brain which is precise to the tiniest details, hence incorporating also memories of events in the past and the thoughts, recollections, and wishes involved. In a word, dear Hylas, when you fall victim to violence and die in an hour, then, before your mortal remains are cold, I will turn on the machine and build a living, thinking Hylas from the same atoms which make up your body now. I guarantee that. Well, what do you say, are you happy?
HYLAS    Yes, sure, of course. You just have to investigate my atomic structure and then enter it to the machine.
PHILONOUS    Naturally. But, my friend, may I still increase your certainty to survive death? You know me, believe in my words, my affirmations, but human deeds are frail, so certainty is imperative here. Hence please let me create that Hylas, which is intended to be your continuation, right now. He will await your death, and when you have died, I will celebrate the resurrection together with him, that is, with you.
HYLAS    What are you talking about, Philonous?
PHILONOUS    You have got that right: To increase your certainty, I will make your copy already now ...
HYLAS     But that's nonsense!
PHILONOUS    But why?
HYLAS    This would be a totally separate, different person!
PHILONOUS    You think so?
HYLAS    Yes, how else could it be? This person can and will be infinitely similar to me, everybody will take him for me, he will have the same sensations that I have, the same wishes and propensities, even the work that I started, he will be able to finish in my spirit, but this will not be me! This will be a double, a twin, so to speak, but I will die forever!
PHILONOUS    Where do you take this certainty?
HYLAS    Well, from the fact that, if you create him on the spot and he will be among us, I will speak of him as "he", like of any other person, and that I will see him who externally looks like myself - and still he will be another person, separate from me, different, like everybody, and the fact that we are as alike as two peas cannot sweeten death for me. Obviously, for those living on, for my friends, my relatives, he will be a perfect illusion of my existence, but I - will die and not live.
PHILONOUS    Where this certainty?
HYLAS    You cannot have the slightest doubt in this matter, Philonous, you just want to put me to the test. Nevertheless, if I picked up this moist, dead leaf from the ground and gave it to this "second Hylas", assuming he stood here with us, so it would be him who would inhale its sharp and pleasant scent, but not me. And things would be similar after my death, since due to my decease nothing would change with him, nothing new would occur. He will continue to exist in this world, enjoy its beauty, I on the other hand will completely cease to exist.
PHILONOUS    So? Well, what should we do then? Tell me what I should do with the machine to ensure your resurrection?
HYLAS    That is quite simple. You just have to create my living and thinking copy after my death.
PHILONOUS    You really think so?
HYLAS    Yes.
PHILONOUS    The copy made after your decease will be identical to you, the one made before your death will not, though it will be person which is similar to you beyond measure, but still somebody else? But where, then, is the difference between these two persons? Please explain that to me.
HYLAS    First, the one created before my decease would be able to see me, like I saw him; he will know that I perish while he was just created, he will ...
PHILONOUS    If this is your only problem, this I can change: The copy will be asleep in both cases thanks to a sleeping draught, and will awake only after your decease, such that he will know neither about the unpleasant circumstances of your death, nor about the way he first saw the light of day.
HYLAS    No, it's not about that. As I see, I was not cautious enough, Philonous. One has to approach this problem with the sharp instrument of reason. Immediately after my death, when I ceased to exist, there will be no method in the whole world by which one could ascertain that this is not me, but merely my copy. Agreed?
PHILONOUS    That's right.
HYLAS    If, however, you had made the copy earlier, then it would be easy to determine that it is not identical to me, because the copy would exist along with me, in a different location. Consequently this would be a coexistence which ipso facto excludes continuation. Yes, now I see where the mistake is. The copy made after my decease that's me, the one made before my death - that is a different, separate person. Don't say that you can arbitrarily choose the moment of his creation, such that there will eventually be only a millionth part of a second between my resurrection and the creation of a double. Don't say that, since although the things seem strange, they must be like that. A special situation has special consequences.
PHILONOUS    Well. You are saying that a copy which was assembled prior to your decease will be a totally separate person, associated to you merely by extraordinary resemblance. A copy, on the other hand, which was made after your decease will be your continuation, i.e., you yourself, right?
HYLAS    Yes.
PHILONOUS    Would you mind telling me what is the difference between these copies?
HYLAS    The moment at which they were created. A parallel existence of me and the copy excludes continuation, but its existence in time after me, after my decease, makes it possible.
PHILONOUS    The existence of the copy after your decease makes your continuation possible? Excellent. So hear now what kind of death the tyrant has destined for you. You shall empty a cup of lethal poison. The agony will last one hour. When should I get the machine going?
HYLAS    When I completely stopped living.
PHILONOUS     If I then made your copy it would be your continuation, i.e., you?
HYLAS    If it has been made after my death, it will.
PHILONOUS    Excellent. If, however, the malicious tyrant ordered his medics to resuscitate you, who has died from the poison, by inserting a quill into your throat and giving you an antidote, then what? The copy which the machine made after your death was - as you yourself said - you. Does this copy suddenly cease to be you, now that you have been resuscitated, and does it suddenly become a totally separate person?
HYLAS    How could this be possible, resuscitating me, a dead person?
PHILONOUS    That would certainly be easier than building a machine which revives people from atoms. Are we discussing technical or philosophical details, my dear Hylas? Is it somehow impossible in principle to bring a newly deceased person back to life? Are surgeons not able to resuscitate someone who died in the operating room, today already? You don't know about this? Please tell me what is the matter with the copy which already was your continuation, what happens to it at the moment when you come back to life due the action of the antidote? Maybe, however, it will not be you who will awake in your original body, but someone completely different?
HYLAS    Impossible. It is totally clear that I will come back to life in the body which the tyrant had deprived of life by means of that poison. At that moment the copy will necessarily cease to be my continuation.
PHILONOUS    You think so? Think about it, Hylas. Can you imagine that actually you are that copy? Well, let us assume that I show you the machine and tell you that actually at this moment you have left its interiors. You obviously feel like Hylas inch by inch - because the machine has reproduced you perfectly. Now imagine that "the other Hylas" which was under the control of the tyrant has been poisoned one hour ago, and right now the medics have brought him back to life by means of an antidote. Do you feel any change in your personality due to that remote event?
HYLAS    No.
PHILONOUS    You see. The copy is a living, ordinary person (that follows from the premises), and there can be no changes in it dependent on what happens to the "original". If the latter is given a poison or an antidote - the copy is neither affected nor changed. Thus we can say: Just as there is no causal relation between you, all the ups and downs of your life, and that Hylas which has been created by the machine - be it for one year, for your whole life or only after your decease - in the same way he is a separate person for you, having nothing in common with you except for an astonishing resemblance. That your existence parallel to that of the copy excludes continuation - agreed. Whether, however, the copy made after your extermination really is you, and whether such a possibility opens up the chance to come back to life again - remains to be proven. Up to now everything is to be said against such an interpretation of the matter.
HYLAS    But wait. Strange how you have complicated things. Look here, my body. When it has died and been exterminated, then an analogous structure may come into being in the future .. ah! I've got it. Now I know. To make the copy, one has to wait until my body stops existing, until its structure has disappeared completely.
PHILONOUS    Consequently the fact if you will come back to life depends on whether your mortal remains have properly rotted or not, if I got that right? Hence your resurrection depends on the rate with which your bones decay. What if the tyrant orders to embalm you, then you will never live again, am I right?
HYLAS    No, damn, you are not! I see that we have to leave living creatures out of our considerations. Some disturbing factor - of fear or trouble - seems to be slipping into statements about humans. Let us discuss the whole matter using dead objects. I have here a precious cameo, carved from ivory. Let us assume that I pulverize it to atoms and make an indistinguishable copy afterwards from these very atoms. What do things look like, then? I see it like this: If we have agreed that the copy shall be the continuation of the original, then it will be like that. If we decide otherwise, then it will not be the continuation. The decision depends exclusively on our agreement, for if we investigated the "earlier" and the "later" cameo, we would be unable to find any difference - since both are the same ex definitione.
PHILONOUS    Finally you shed some light on the problem. Your last conclusion, applied to humans, goes like this: When you have died by seven o'clock, and I have reconstructed you from atoms, you will - depending on what agreement we have made - continue or not continue to live. Doesn't this seem totally absurd to you, too? If, however, you had died in the operating room under the knife of the surgeon, but medicine will be able to bring you back to life, would you still say that you are living or not living, depending on the agreement we made?
HYLAS    The difficulty, as I see it, is that with respect to any thing objectively existing around me an arbitrarily made agreement (convention) decides about the problem of continuation. If, however, I subject myself to an analogous experiment, the mere completion of a convention leads to nothing but nonsense. I do not understand why this happens. For humans are material objects as well as a rock, a flax fiber, or a piece of metal!
PHILONOUS    I will show you the source your confusion springs from. When we embark upon creating the continuation of any object, we are at the same time choosing concrete criteria which decide if there really is a continuation, i.e., if one and the same object continues to exist now the way it did in the past. Hence when we define the state of the matter we choose implicite (sometimes explicite) the methods which serve to determine this state. My consciousness, however, is directly given to me, and the method which has to determine at this moment whether I am conscious does not depend on me absolutely. Other people can treat me as an object and make agreements concerning my possible existence after my death and my reconstruction from atoms. I am the only one, however, who is not able to act in this way. This is about a general, methodological problem. An arbitrary body reveals to us its various properties depending on which method we apply to investigate it. The human consciousness, however, reveals itself to its owner in the most direct, original, obvious way, without the application of any method or - if you like - through "the same method" for all conscious, normal humans. One can entertain the most serious doubt concerning the structure and formation mechanism of consciousness, but there is no denying its existence in identical form in any given individual.
HYLAS    You know what? I think you are asking me the wrong questions. The whole problem is inappropriately posed since it comes down to an argumentum ad hominem. You ask me about future things that I have to think up since nobody has experienced them yet. And that's not all: Essential here are only my premortal statements, because when I have died, and you are questioning the copy made in the machine after my death if he is me, so he will of course answer in the affirmative, will claim to be Hylas, the same which has had this conversation here with you. So everything I have said about the future which is supposed to begin after my death and the restoration of my body from atoms, but, above all, everything about the question if I will or will not continue to live, all this, dear Philonous, are only my subjective ideas, expectations, thoughts, anticipations, doubts, and nothing else.
PHILONOUS    How am I supposed to understand this? So the machine does not bring the dead back to a new life?
HYLAS    This I did not say. I do not know how things stand. But there is no scientific proof here for anything. No decisive experiment can be performed since when questioned, the copy will claim to be me, and there is  and will  be no way of finding out if he is merely a double. Hence if one intends to stick to empirical science then one has to declare the whole problem an apparent one, now and forever, and my statements or those of other persons can one give evidence for certain peculiarities of the human mind, but they say nothing about future events. If it still seems that they do, though, then this is language abuse, and nothing else. Yes, Philonous, it is an apparent problem, I am sure about this now.
PHILONOUS    You are right, there is no empirical solution to that problem. Since even if we had that machine here in front of us, if you were ready to do the experiment and woke up again after your execution, it would remain uncertain if it were you who rose from the dead, or only a person who is similar-looking, a twin, as it were. Here we face the logically exact case of an alternative: either the copy is the continuation of the original, or it is not. Each contingency - if we assume one of them is true - leads to certain conclusions. If these conclusion lead to logical contradiction, we have to discard them, together with the resolution of the alternative by which is was produced. In this way we will discover the possibility which is free of logical contradiction, and take it for the one which corresponds to reality with certainty. In any case, it is no apparent problem, in my opinion. An apparent problem is a problem which does not exist at all. If the aforementioned problem does not exist, you have no reason to worry about the things that will happen at the seventh hour due to the plans of the cruel tyrant.
HYLAS    You are joking, Philonous, the problem, however, is serious and deserves objective consideration. Being sentenced to death I'm worrying since my fixed execution is a fact which is supposed to happen, and not an apparent problem, the possibility of resurrection which I have demonstrated and which was accepted as unshakable, on the other hand, contains mysteries which are hitherto not understood, let alone unriddled by anybody. Let us try to investigate the problem of continuation using humans as an example. Suppose there is some human X, and in his lifetime we use the machine to create a copy called X'. X and X' have the same feeling of their identity, and the have the same memories stored. When questioned, one will answer that he has experienced the same things as the other one. In reality, however, only X has experienced what he is talking about, whereas it is only illusions to X'. Hence not only the atomic structure, but also the genetic connection of the present structure to the preceding structure is giving evidence about the identity of a human. In this way we have saved the concept of identity for our investigations, by making the genetic element part of that concept. This identity can be called genetic identity according to Lewin.
PHILONOUS    I listened to your train of thought with great pleasure, dear friend, however I think it did not contribute to the solution of our question, but on the contrary - it lead us farther away from it.
HYLAS    And may I ask why?
PHILONOUS    First of all you try to show in a different manner than before that continuation is impossible under the condition of coexistence. Second you demand that we acknowledge the concept of genetic identity as imperative for the proof of continuation. But this is just what makes the functioning of the machine impossible, for what are the consequences? If the tyrant gives order to his thugs to hold your mouth shut for a certain time, you have to die. Some scholar, obsessed with your doctrine of genetic identity, will claim after a careful examination of the body that the deceased is genetically identical with Hylas, that he is the continuation of Hylas, it's just that this continuation is not alive any more. In this way he will undoubtedly discover a true fact, but not quite the very latest one, namely that a dying person is about to become a deceased, and that this deceased is the same person, just not alive any more, but this discovery will not provide the slightest help in shedding some light on this matter. You yourself gave up the postulate of genetic identity at the beginning of our talk when you rightly remarked that it is not the conservation of the same atoms, but the preservation of the same structure which decides if one feels to be a homogeneous personality. Suppose the thugs cut your hands off, the machine however creates new, living hands for you, which naturally grow on your arms. Will you continue to be yourself?
HYLAS    Of course.
PHILONOUS    And now the thugs cut off your head, but I can successfully create a copy of your body by means of the machine, and that copy in turns grows on your head. Will it be you who returns to life in this way, or just your double?
HYLAS    I myself.
PHILONOUS    And if I make a complete copy with all the limbs after your death, it will not be you anymore?
HYLAS    Wait! A new thought occurs to me. A little while ago you were talking about the procedure of carrying out observations, i.e., about methods that we choose to establish whether or not there is continuation of an object. This observation has to be continuous, hasn't it? Only such a method is natural and appropriate.
PHILONOUS    Not at all. Every one of us who is retiring to bed after a hard day is sometimes sinking into such a deep sleep that he is actually losing consciousness of his existence. However, when you awake in the morning, you now with certainty that you are the same Hylas that went to bed the evening before, despite this break.
HYLAS    Yes, indeed. You are right. But listen, isn't it true that we pay too much attention to the expectations of a person who has to die? Maybe the problem disappears all by itself if the person does not know anything about his sudden death? Well, that man goes to bed and has no foreboding. When he is overcome by sleep we kill him and put a sleeping atomic copy on his bed. When it/he awakens, couldn't we say then that a continuation has been created, that this is the same person who went to bed the evening before, and that this is the whole truth?
PHILONOUS    My dear Hylas, it's been a long time since I heard so many thoughts coming from you which are so full of logical mistakes. First of all, certainly unconsciously - I do not want to assume anything else - you made clear that, if we murder someone in his sleep or - more generally speaking - in such a state which prevents him from suspecting anything about his imminent murder, that we will cause less harm to him than in the case when he is conscious of his near end. I will pass over that problem in silence since it belongs to ethics. Secondly I begin to suspect that you are guided by totally irrational, metaphysical fears. For some obscure reasons it seems to you that a copy - which has been made after the death of a person - has to be as close as possible to the place where that person ceased to exist. In the case that you mentioned, going to the same bed and falling asleep should allegedly provide the best conditions for a successful "switching" of the personal self from one body to the other, from the one that ceased to exist to the one which begins to exist. That is a sign of the irrational belief that the "self" is a unified whole, an indivisible, irreducible entity, and that self has to be transferred from one body to another, which is an archetypal metaphysical interpretation, which couldn't be any purer. It is, however, not important whether or not the circumstances that are created by the external situation correspond to our naive ideas, like, for example, the spatial proximity between the deceased and and the copy, the state of unconsciousness (I think you referred to the case of the operating room and you tried to make the situation similar to that one), but it's all about using the tools of logic to develop hypotheses which are equally valid under all special circumstances in which a resurrection from atoms is conceivable at all. That would be a poor theory of gravitation which was valid only for apples falling down to earth, but was totally helpless with respect to peas or moons. What do you think about the following future perspective? Everyone who is leaving for a dangerous expedition to the stars leaves his atomic "personal description". As soon as the message arrives that he died on the expedition, his family switches on the machine, and the deceased steps out of it, healthy and in good spirits, to everybody's delight. Now, if that man had died in the flames of Sirius, would you still say that the copy is the continuation of the deceased, or does the large distance between the places of death and resurrection deter you from such an explanation?
HYLAS    True, since there is no principal difference between my case and yours, concerning the essence of re-creation, we have to say that the copy is a continuation.
PHILONOUS    You really think so? But what if the message turns out to be wrong, and the one who had left for the journey returns healthy and unscathed, then what?
HYLAS     Then it will of course turn out that the family was wrong and that the man made by the machine is just an imitation, a copy, i.e., a double.
PHILONOUS    So what does the authenticity of continuation depend on? On the fact whether the news of the person's death was accurate or not?
HYLAS    Yes.
PHILONOUS    So what correlation is there between some information coming in from the stars, and the structure of a person who comes out of a machine in which he was assembled from atoms? Between that information and his thoughts, his whole personality? None. Right?
HYLAS    None, indeed.
PHILONOUS    So how can that which has no connection to the person and personality of someone decide whether he is the same who set out for the stars, or just similar, a completely other person, a double existing in parallel to the former?
HYLAS    Actually, I don't know. Please, dear friend, let me try to approach the problem in a different manner. When you have made a copy of someone after his death, you can call it his continuation, or you can decide not to do so, the argument is just about words, because the fact remains the same: That person continues to exist and to live. It is the same as arguing if I am still the same person that I was yesterday, or if yesterday's "self" is already gone. You cannot solve this problem with words, nor can you decide whether the copy is "the same person" or just "a similar one". The difference is irrelevant because it does not change the hard fact, the actual existence. Therefore this alternative is only an apparent one.
PHILONOUS    An apparent alternative? So we have no alternative at all? How is this possible? But there can only be one single way things can possibly stand: Either you get killed by the hand of the tyrant, and Nothingness will engulf you for all eternity, in this case your copy would only be an almost identical twin who perfectly replaces your loss to everybody, but you yourself will never exist again - or you yourself will open your eyes again, thanks to the machine, you will see the sky, the friend, hear the song of the birds and inhale the sweet zephyr into your lungs. Is there another, third solution?
HYLAS    I do not know. Possibly yes. Might I think aloud? As long as a man lives, his continuation is impossible. Agreed?
PHILONOUS    Parallel to him - it is impossible. Agreed.
HYLAS    When he ceases to exist, his continuation becomes possible - for the whole world. That much is certain. But for him ...? I think we have an abuse of grammar here, because if we say, or ask, if "for him" a continuation is possible, then we are talking about a dead person, a dead person however is someone who is not there anymore, who stopped existing, as if he had never existed - since perished are his sensations, his consciousness, his memories, and so on. Therefore this is a case of improper use of the syntax.
PHILONOUS    Well, you're a fine one. You want to blame it on the syntax? But I am not discussing with a deceased, but with you, if only a few minutes before you will turn into a deceased. Wait a minute. You have mentioned previously that one cannot decide with words only if you were still the same as yesterday, or if yesterday's self is gone already. I do not see the slightest difficulty to decide this problem. If I ask you where your garment of yesterday is, you understand by that the garment which you wore yesterday, don't you?
HYLAS    Yes.
PHILONOUS    A garment is no more, no less material than you are, therefore in this material sense the Hylas of yesterday still exists today. Concerning your subjective emotions, however, that were on your mind yesterday, there is no problem either. Today I do not see a certain crease in garment any more that had formed there yesterday when you were sitting on the threshold of your house for a while. A very careful investigation of the garment, however, would certainly permit to detect some displacement of molecules in the fabric which was caused by you pressing a crease into it yesterday. This displacement could be called, only metaphorically of course, the "memory" of the crease. Now you see that all objects - including our bodies interpreted as objects - which existed yesterday continue to exist today. Our impressions, however - more generally speaking, yesterday's states of our consciousness -, exist exclusively in our memory, and the only marks they are leaving are certain changes of the brain's molecular structure which constitute the memory. As you can see, things can be perfectly explained, we just have to be very careful as to what meanings we ascribe to words. Both the sentence "my self of yesterday still exists" and the sentence "my self of yesterday does not exist" are in accordance with truth, namely in the following way: If you interpret "yesterday's self" as my material, visible body, then I exist as the one I was yesterday. If, however, you interpret "yesterday's self" as the complex of thoughts and feelings which were present in my consciousness yesterday, than we cannot ascribe an actual, current existence.
HYLAS    I admit that I was wrong. But please tell me of what use your train of thoughts is to our problem?
PHILONOUS    Of no use. Because objectively the copy - after making an agreement - either is the continuation of the original, or it is not, if we make a different agreement and choose other methods to check the state of affairs. The whole problem, however, is based on the fact that we have to decide on its subjective property, i.e., we have to determine if one can logically deduct that after a re-creation of the brain from atoms the consciousness of the deceased to which this brain once belonged will come to life again, or if this train of thought is leading to logical contradiction.
HYLAS    Yes, you are right. That's were the error is hidden. We continue taking the subjective interpretation of the matter for the objective one. If the whole experiment cannot be objectively performed, logic cannot get it under control, and our considerations are futile.
PHILONOUS    You think so? Well, Hylas. I will now change the modus operandi . It will become completely objective. This will at the same time remove the dilemma which results from the simultaneity or non-simultaneity of re-creation. Don't you think this would considerably elucidate and simplify the problem?
HYLAS    I can gladly say that I agree with you. So please, speak on, my friend, I am listening.
PHILONOUS    I will not examine one more person, I will not torment your soul which seems scared to death with questions that would be quite inappropriate under the prevailing circumstances, the only thing I will do is this: First I will kill you, then I will make a copy of you, not only one, dear Hylas, but infinitely many, to be sure. Because when you have died (and you have only five minutes left to live) and I make numerous copies of your person, then you will exist as a multitude of Hylasses, as an incalculable multitude, since I promise you that I will not stop until I populated all planets, suns, stars, moons, spheres, and celestial bodies with Hylasses, and that's because of the love that I feel for you. What do you think about that? Could you become omnipresent in the universe this way, you alone?
HYLAS    That would be very strange. Is there a logical contradiction in it?
PHILONOUS    I didn't say that, you have to find out for yourself. Thousands of Hylasses will live their life, applying themselves to various occupations and pleasures. But how is it, will your one self be divided and existing in all of them at the same time, including them all? Or will all copies be linked into a single entity by the mysterious ties of a single personality?
HYLAS    That's impossible. Every such individual must have his private, own, subjective self, it's just similar to mine.
PHILONOUS    Each one - that's what you are saying - has a self similar to yours? And not the same?
HYLAS    Not the same, because then they were a single human, which is a contradiction.
PHILONOUS    Excellent. Each one then has a similar self as you have, Hylas. And which one of them has the same as you and represents your continuation? Why are you silent? What does logic say now?
HYLAS    Logic says, no-one. But wait! I think something has dawned on me. But yes! Of course! Dear friend, the matter is as follows. Identity is determined not by total material correspondence, but correspondence of the structure, as we agreed, didn't we?
PHILONOUS    That's true.
HYLAS    Concerning the structure, however, one can say that it is "the same", not just "similar". Well, I am drawing an equilateral triangle. If I draw a second one, I can say that both have "the same" structural property of being equilateral. I can draw many such triangles, but from a structural point of view they are actually just one single triangle, repeated many times. In the same way I can say that all Hylasses which have been created by the machine are actually "the same" human, being simply repeated x times. What do you think about that?
PHILONOUS    You gave a very clear presentation of the matter. Do you permit me to create a copy right now already, while you are still alive?
HYLAS    Why that?
PHILONOUS    Well, since the copy is no different person, but simply "the same", and since, as you said yourself, from a subjective point of view (and this is the one that it's all about) it is "the same" human being as yourself, it follows that you - when the tyrant has killed you, but the copy stays alive - will be alive, since a person will continue to exist which is "the same" Hylas as you. Or do you take a different view?
HYLAS    So I was wrong? But why? If one takes only inanimate objects into account, will there arise a similar dilemma ...?
PHILONOUS    Yes, a dilemma will arise, but we are instantly eliminating it by arbitrarily fixing our views. Whether or not we are accepting the copy as a continuation of the original, depends entirely on our agreement. If we deal with human beings, however, things look different, since here the phenomenon of consciousness is thwarting our plans. Because we might take one earthenware mug for another, similar looking one, or maybe one twin for the other, since we are observing them from outside, taking them for objects. But one twin will never take himself for the other one. Just as you cannot "accidentally" take yourself for your copy which exists parallel to you and was created by the machine. So what shall we do? The tyrant will arrive any minute now. Do you know, by the way, what kind of death he destined for you?
HYLAS    You said that I would be poisoned, but later you talked about strangling.
PHILONOUS    Just as an example, just to illustrate my argumentation, not exactly corresponding to what he wants to do. You shall suffer a different death. The tyrant will have your body frozen, until all motions and subtlest oscillations of the atoms have ceased, until the tissue solidifies, the living processes stop, the structures have died. Will this mean death to you, Hylas, when you - included in an ice floe - will be sent to the bottom of an arctic ocean?
HYLAS    Beyond any doubt.
PHILONOUS    And if I, your friend, get the ice floe back from the depths, thaw it and your frozen body carefully and administer the appropriate medicine such that all molecules start moving again and you come back to life, what will then happen? Will it not be you - the way you are standing here, seeing me in front of these autumn trees - who will be coming back to life, from your icy prison, from the darkness of non-existence brought to the bright light of day?
HYLAS    Yes, that will be me.
PHILONOUS     You do not entertain the slightest doubt?
HYLAS    Not the slightest one.
PHILONOUS    And if you are sprayed to atoms and I rebuild you from these very atoms, will this not be you any more? And if not, why not? Will your personal self escape your body, like a bird escaping a cage whose bars are broken?
HYLAS    Also in this case, I think, I will come back to life again.
PHILONOUS    You yourself, Hylas, and not just a person who is infinitely similar to you?
HYLAS    Myself.
PHILONOUS    Well. And if two copies are made of you, one from the very same atoms of which your body is composed now, the other one only from similar atoms, will the first copy be your continuation, your true self, with the other one merely being your double?
HYLAS    Maybe.
PHILONOUS    But these atoms cannot be distinguished in any possible way. Neither do the copies differ in any way; so why should one be your continuation, the other, however, a completely separate person?
HYLAS    I do not know. Indeed, the same or just similar atoms - it seems that it doesn't actually matter. All atoms are identical, and cannot possibly be distinguished from each other.
PHILONOUS    So both copies would be your continuation? Or none of them? Why don't you answer? The seventh hour is drawing closer, and we have to expect the tyrant who is approaching with his thugs, but you, Hylas, are constantly announcing different and diametrically opposed opinions, although I offered you all possibilities of resurrection that a real materialist can only dream of. Now you are claiming that the problem of your continued existence depends on an agreement, then again you admit a multitude of continuations which is totally absurd, now you say that your resurrection from atoms depends on the rate with which your body decays, and in this way you go round in circles all the time. So please tell me your ultimate opinion, dear friend. The tyrant is already coming closer, I can see, in the distance, at the end of the avenue, his robe, stained with the blood of your predecessors. Quick, tell me how I should use the machine in order to bring you back to life, and tell me if you are convinced that you will open your eyes again, thanks to the re-creation from atoms. Will you open your eyes again, dear Hylas? Tell me, will you ever open your eyes again?
HYLAS    Indeed, I do not know anything any more, dear friend Philonous. I am afraid you did something terrible, trying to prove per reductionem ad absurdum that apart from atoms and their structures there is something more, and that exactly that mysterious "something" renders the "re-creation" of a human, his resurrection after death, impossible; since one can only call  a similar, but not the same individual back to life. Should this be the proof of the existence of the immortal soul, and should it be you who is the originator of that proof?
PHILONOUS    Not at all, dear friend. Per reductionem ad absurdum I have only demonstrated that the hypothesis which you tacitly assumed to be an obviously correct one is untenable, namely that consciousness could be reduced to atoms or their structures. Consciousness, however, is neither one, nor the other - quod erat demonstrandum. This does not imply that is is no material phenomenon. The subject is generally a very complicated one and deserves an investigation using other, newer methods. Maybe we will be able to proceed from mere criticism to positive results by applying the joint knowledge of such seemingly separate sciences like psychology and the theory of electrical circuits or thermodynamics and logic. Only such considerations which include the latest discoveries of science will permit us to shift the bounds of knowledge - if only by an inch.