Free Will and Choice – Lesson 15

Table of Contents

• Summary of the course: determinism, libertarianism, and physics
• Neuroscience and the inability to decide
• Philosophy, arguments, and the lack of a conclusion
• Self-diagnostics and thought experiments as a starting point
• A response to skepticism about intuition
• Avshalom Elitzur’s thought experiments: duplication, identity, and soul
• Leibniz’s principle of the identity of indiscernibles and the critique of it
• Continuity of identity, cell replacement, and the Ship of Theseus in halakhic and scientific context
• Critique of popular science, “intelligence” in sperm cells, and the distinction between performance and understanding
• The Turing test, the film “Her,” and the claim that a computer has rights
• Dualism, determinism, and libertarianism: relations of implication

Summary

General Overview

The lecturer sums up a course on neuroscience and free choice and reaches the conclusion that there is no scientific or philosophical way to decide between deterministic materialism and a dualist view that could allow libertarianism. He argues that in a closed physical world there are no “gaps” for free choice, and that chaos, quantum theory, and complexity/emergence do not solve that either. Since brain experiments such as Libet’s experiments, split-brain studies, and brain injuries undermine only naive conceptions of free choice and do not decide between the models, he proposes at the final stage a kind of “self-diagnostics” through thought experiments in order to uncover a person’s own intuition, especially where there is no decisive objective proof.

Summary of the course: determinism, libertarianism, and physics

The lecturer presents two main models, deterministic and libertarian, and emphasizes that free choice is not action “in a vacuum” without influences, but a complex position that recognizes the influence of environment, genetics, and education without thereby determining determinism. He argues that embedding free choice within a physical worldview is impossible because in physics there are no gaps, and once the given state is known, the next stage can be inferred. He states that chaos, quantum theory, and complex/emergent systems do not create a gap in physics and therefore do not solve the problem of choice. He poses a dilemma between a materialist worldview that does not allow free choice and a dualist conception of body and mind/soul that could allow it, and concludes that the physical option probably does not exist.

Neuroscience and the inability to decide

The lecturer says that neuroscience is not capable of deciding experimentally between the two options, not even through Libet’s experiments and possible continuations of them. He explains that split-brain cases and brain injuries attack a naive conception of libertarianism, but do not refute a more complex conception that recognizes many influences on action that are not deterministic influence. He objects to the common claim that today the tools of neuroscience can decide this philosophical question, and concludes that even in the foreseeable future he does not see how scientific tools could decide it. He states that the question returns to being philosophical, as it was about a hundred years ago.

Philosophy, arguments, and the lack of a conclusion

The lecturer notes that on the philosophical level, arguments have been brought in different directions, including Newcomb’s paradox and considerations of logical determinism, but even there there is no unequivocal conclusion. He argues that the deterministic materialist can usually answer the arguments or reject assumptions and remain in his position, and therefore the question remains unresolved. He says that in his view there are some pretty good arguments in favor of libertarianism, and it seems to be in a better position than deterministic materialism, but that still is not a decision.

Self-diagnostics and thought experiments as a starting point

The lecturer suggests that when philosophy and science do not decide the issue, a person can carry out “self-diagnostics” through thought experiments in order to clarify what his intuition is regarding free choice. He distinguishes between a thought experiment in the style of Einstein, which tests consistency between intuitive insights, and thought experiments whose purpose is to expose a person’s hidden beliefs about himself. He gives an example from moral perception and raises the possibility that an atheist committed to morality may be a kind of “hidden believer,” in a way that illustrates how examining the implications of one’s positions can expose assumptions a person is not aware of. He emphasizes that a thought experiment does not reveal “what is true,” but rather “what you believe,” and that where there is no decisive evidence, a person relies on intuition as a starting point, in the sense of “the burden of proof is on the one who wants to overturn the default.”

A response to skepticism about intuition

The lecturer argues that if there is no trust in intuition where there is no other evidence, then there is no trust in anything, and there is no way to answer radical skepticism. He gives the example of a mirage in the desert to show that a person does not stop believing his eyes because of one isolated mistake, but continues with his initial intuitions until undermining evidence appears. He adds that even “objective tools” rely on intuitions, such as trusting a lab technician’s eyesight in observation.

Avshalom Elitzur’s thought experiments: duplication, identity, and soul

The lecturer presents thought experiments from Avshalom Elitzur’s book Time and Consciousness, published by the Open University series, which are meant to support the existence of a spiritual dimension in the human being within the framework of dualism versus materialism. He proposes a scenario in which a person is killed painlessly and an entirely identical creature is built molecule by molecule, with all the same memories and brain structure, and he argues that most people would refuse, which in his view hints that they assume identity is not exhausted by matter. He uses the image of the cursor on a computer screen and the formalism of “creation and annihilation operators” to illustrate the idea of replacement without real “movement,” and asks whether one may relate to a person as though he were a cursor that can be turned off and turned back on. He adds a version involving a million dollars in order to sharpen the distinction between “sleep” and “killing and rebuilding,” and also raises a scenario of dismantling a person and reassembling him from the exact same cells and molecules, and argues that refusal even there points to belief in something beyond matter, namely mind or soul. He refers to the statement about Rava and Rabbi Zeira and distinguishes between bringing back the same soul and creating an identical body without a soul, and argues that refusal in such an experiment serves as a self-test of whether a person is really a materialist.

Leibniz’s principle of the identity of indiscernibles and the critique of it

The lecturer presents Leibniz’s principle of the identity of indiscernibles, according to which two bodies with the same set of properties are the same body, and brings Leibniz’s proof by contradiction by means of the property “is not B.” He argues that there is a mistake in the argument, and that there may be two different objects with the same set of properties, because the object is not just a collection of properties but rather “the bearer of the properties.” He explains that in his opinion, “A is not B” is not a property but points to the otherness of the object itself, and therefore no contradiction arises in the set of properties. He notes that a materialist could argue that refusal of the duplication experiment does not require a soul, but only a metaphysical distinction between the substance and its properties; however, the lecturer says he is not sure about that claim, and in particular finds it hard to accept when the person is dismantled and reassembled from those very same molecules and cells.

Continuity of identity, cell replacement, and the Ship of Theseus in halakhic and scientific context

The lecturer says that human beings replace cells all the time anyway, until no original cells remain, and yet they still relate to themselves as the same person, and he connects this to the Ship of Theseus, in which parts are replaced until no original material remains. He brings a halakhic example from Ritva and Tosafot about a house regarding which people vowed or stipulated that they would not enter it, and afterward it collapsed and was rebuilt, and asks whether that is “the same house.” He describes gerontology projects aimed at extending life and achieving eternal life, including de Grey and experiments on hydras with “pulses” of contraction and regrowth, and notes that prizes were offered for proving the project impossible and that no decisive proof against it was presented. He asks in what sense “the person a thousand years from now” will be the same me, and argues that these questions point to a dimension in the human being beyond biology, including the connection to continuity of identity and concern for the future, such as pension planning, and he mentions an idea of Adi Tzemach that concern for my future self is similar to concern for others.

Critique of popular science, “intelligence” in sperm cells, and the distinction between performance and understanding

The lecturer criticizes articles in the popular press that present philosophical sensations based on scientific findings, and gives the example of an article that claimed sperm cells have “mathematical ability.” He compares this to the fact that water “solves” complex equations such as Navier-Stokes equations and turbulence without thereby being intelligent, and argues that this is a mathematical model used by the describer, not a conscious solving of a system of equations. He defines intelligence as judgment and understanding on the part of “someone” who chooses tools and decides, and not as the performance of an innate or programmed function; therefore, a bird, water, and a computer are not intelligent in the philosophical sense. He notes that in the world of artificial intelligence it is customary to measure intelligence by task performance, but in his view that is a useful research definition, not a philosophical truth about understanding.

The Turing test, the film “Her,” and the claim that a computer has rights

The lecturer presents the Turing test, in which a written conversation that cannot be distinguished from a conversation with a person is supposed to justify treating the computer as though it were a person, and connects this to the possibility of falling in love through correspondence and to the film Her. He notes that there have already been cases in which a computer passed a Turing test against a child of about thirteen, in the sense that a reasonable person could not tell the difference, and argues that the question is whether such success really turns software into a person. He rejects the distinction between organic matter and metal and wires as a criterion for rights, but also rejects Turing’s functional criterion, because in his view a person is not a collection of functions but “the bearer of the functions.” He argues that a computer that behaves as if it were intelligent is like water or a bird in that it has no understanding or awareness, and the intelligence belongs to the programmer or the builder.

Dualism, determinism, and libertarianism: relations of implication

The lecturer concludes by saying that the experiments he described test the question of materialism, not the question of determinism—that is, whether there is something in the human being beyond matter. He argues that one can be a dualist and still be a determinist, because one can assume that the mind, too, operates deterministically. He states that dualism is a condition for libertarianism but not a sufficient one, and formulates the point by saying that in his opinion dualism does not imply libertarianism, but libertarianism does imply dualism, because within physics it is impossible to insert free choice. He promises that next time he will propose a thought experiment that tests free choice directly and not only the existence of mind, and adds, regarding artificial intelligence, that a computer neither understands nor is aware, but merely moves electrons, even if it performs tasks that the programmer himself cannot perform.

Alright, so let’s begin. We’re basically getting to the last stage of our track. My plan is to finish it today, to finish this track today. I may still have one more session or two on choice in general, but this is basically the end of the discussion about neuroscience and free choice. Let me briefly summarize where we stand. We first examined the two models: the deterministic model and the libertarian model, whether there is or isn’t free choice. We set up somewhat more sophisticated and less sophisticated models, and not naive ones that say free choice means some kind of action with no influences at all, out of a vacuum. After I set that up, I tried to see whether free choice can be embedded within a physical picture of the world. And I said that it can’t, because in the world of physics there are no gaps. Therefore, once the given state is fully known, then I also know what the next stage will be. There is no possibility of choosing between two options if we are in a world that is entirely physics. We talked about chaos, we talked about quantum theory, and in the end I also talked about complex systems, or what I called emergence, and all of those things in fact do not reflect a gap in physics and therefore do not solve the problem. So in the end we are left with a dilemma between two possibilities: a materialist worldview, meaning a physical one, which does not allow free choice, versus a dualist worldview, in which there is something beyond physics, body and soul or spirit, which can allow free choice. Therefore, the option of embedding free choice within physics apparently does not exist, at least to the best of my understanding.

Then I moved on to examine this: fine, so how do we decide which of the two options is correct? So I moved to talk about neuroscience. And in neuroscience we saw that there is really no way to decide experimentally, in a scientific way, between these two options. We saw Libet’s experiments and all their possible continuations, some of which haven’t even been done yet, but even if they are done, in the end they still won’t settle the question. And regarding split-brain issues and brain injuries, which were the last sessions, there too I showed that this attacks the naive view of free choice, of libertarianism, but not the more complex view that recognizes the influences of environment, genetics, education, and everything within which we operate, on our actions. The difference is only that this influence is not deterministic. Meaning, it does not determine what I will do; it influences what I will do.

So in the end we are seemingly left high and dry, because we are trying to resolve this question. After all, many people claim that now, with the tools of neuroscience, we have the possibility of settling this philosophical question with scientific tools. So far the conclusion is that this is not possible. Certainly it hasn’t been done. But on the face of it, in the foreseeable future, or in ways I’m able to think of, I also don’t see how this could be settled scientifically. And so we basically go back to the situation we were in, I don’t know, a hundred years ago. A hundred years ago, no one even imagined settling scientifically the question of determinism versus libertarianism; it goes back to being a philosophical question.

Now what happens on the philosophical plane? So on the philosophical plane too—and this was also one of the chapters in the past—I brought arguments in every direction. I talked about Newcomb’s paradox, I talked about considerations of logical determinism, and we tried to show how, from philosophical arguments, one can try to decide whether there is or isn’t free choice. But there too the conclusion was not unequivocal. The conclusion was not unequivocal, and the deterministic materialist can always somehow explain away the argument, or answer it, or reject one of its premises and remain with his own position. In short, the question is unresolved. It cannot be settled on the philosophical plane, nor on the scientific plane, and if so, what do we do?

And that brings me to the final stage. After we failed to settle it, I think that on the philosophical plane there are definitely some pretty good arguments in favor of libertarianism, and it seems to me to be in a much better position than deterministic materialism. And still, that’s not a decision. And on the scientific plane, as I said, it can’t be decided at all; at present it doesn’t even seem relevant to the question. So what do we do?

Here I suggest that in the last and third stage, when a person wants to formulate a position for himself, if philosophy doesn’t work and science also doesn’t help him, then what you can do is what I call self-diagnostics. That is, I’m basically suggesting that a person carry out thought experiments that will check where he stands with respect to this question. What does that mean, thought experiments? A few words about this in order to understand the point.

Look, in the history of science there have been a few very famous thought experiments, like Einstein’s experiment in which he showed that you must arrive at special relativity if you assume that the speed of light is constant. So he did some thought experiment with mirrors, never mind, and tried to show that when one sees light—actually not only light but reality in general—from a moving system, then time flows at a different rate than when the system I’m in is at rest, and space does too. He showed that through a thought experiment. The thought experiment Einstein did was not a laboratory experiment. He simply built some theoretical structure: a mirror here, a mirror there, I send the light like this, then I ride in a little cart and check how long it takes the light to get from here to there—but all that he did in his head, meaning on paper. He didn’t actually do the experiment.

What does such an experiment give you? What such an experiment gives you is basically this: given a set of data, I’ll tell you what the expected result is, and that expected result can sometimes surprise you, and then it means that apparently you need to give up something among your assumptions. Or in other words, a thought experiment of Einstein’s sort checks consistency between intuitive insights I have. Meaning, it shows me that if I have several certain intuitive insights, and another intuitive insight, they don’t fit together. Because I’ll do an experiment in which I apply the intuitive insights I have, and I’ll show you that that other insight does not hold, and therefore you need to straighten out your system. There is some internal contradiction there; you need to change or give up one of the intuitive principles you hold.

I’m talking about something else. I’m talking about self-diagnostics. What do I mean? A person wants to clarify where he himself stands with respect to some question, and it’s not always easy for us to answer that. Meaning, a person asks himself: do I have free choice or not? Okay? There are many people I can imagine who are very torn about this; they don’t know how to say what their view is. Not what is correct—we discussed what is correct: science, philosophy, I don’t know, it’s not settled. I’m asking what their own view is, what my intuition says, what my starting point is.

Now, thought experiments can help you expose the intuition hidden within you. You can discover what you believe, not what is correct. A thought experiment does not reveal what is true; it reveals what you think, through all kinds of trials that you put yourself through, or I help you go through, and by means of that you discover what you think. This is a point many people are not aware of: very often a person expresses some position on a certain issue, and if you dig inside, you’ll see that it’s not really his position. He himself does not fully understand what he thinks.

Just one example. One of the kinds of proofs for the existence of God—in my book The First Being I dealt with this in the fourth discussion—one type of proof is the proof from morality. Whoever has binding morality in his world, in my opinion such a thing cannot exist without God. Meaning, binding morality, valid morality, cannot exist without some kind of belief in a transcendent factor in the background. I’m not talking specifically about the God of Sinai, or the giving of the Torah, or Judaism or Christianity. I’m talking about something—a transcendent factor that gives validity to the rules of morality.

Now the fact is that there are many atheists who are very committed to morality, behave morally, care about morality, struggle for moral implementation, and so on. How do I reconcile that? How can an atheist nevertheless behave in a way that, in my opinion, can characterize only a believer? So one way to reconcile this is to say that he is really a hidden believer. Meaning, if you ask him, he’ll tell you he’s an atheist—and not because he’s lying; he really thinks he’s an atheist—but through his moral behavior I can try to show him that he is not correctly decoding himself. In fact, he believes. He’s just not aware of it, or not admitting it, even to himself. But his commitment, his devotion to morality, shows that he really does believe in God in some sense.

And many times you can expose certain assumptions in a person that he himself is unaware of, through their implications, by trying to show him: look, in such-and-such a situation, what would you do? Or what do you say about such-and-such a situation? Notice: if you say that, let’s go back to the question of God—you’ll see that it can’t be that you don’t believe. If you didn’t believe, you wouldn’t say what you say about the situation I presented to you. Okay? Again, I don’t want to get into the argument itself because you can debate it endlessly. What I want to show is the logic. Thought experiments are a very important thing. They never teach you something new. Maybe experiments of Einstein’s kind do, but experiments of the kind I’m talking about don’t teach you something new. They teach you something that is already inside you, something you already believe, but you’re not always aware of it. And the role of the thought experiment is to bring that into your awareness, so that you know where you stand.

Now, what I want to argue is that many people who are torn over the question whether we do or do not have free choice—if I put them through a few thought experiments, I can reveal to them that they themselves think they have free choice. Even though in answer to the first question they might have said, “I don’t know,” or “I think I don’t,” or “I’m conflicted,” or whatever. But after I put them through a few thought experiments, they may discover that deep down they do believe in free choice.

Now what does that mean? It may be that they believe in free choice—so what? People can believe all kinds of things. Does that say anything about the world, that we really do have free choice? No. It says only what I myself believe. But why is that important? Because in a place where there is no objective philosophical or scientific or other decision that can show me what is correct, then how do I formulate a position about something? I simply go with my intuition. If it seems to me that I have free choice—if it seems to me that there is free choice, if I discovered that it seems to me there is free choice—then now someone who claims I don’t have free choice will have to prove it. Meaning, as long as he hasn’t proved it, I remain with my own perceptions.

In that sense, this self-diagnostics, these thought experiments that help me discover what I myself think, are very important precisely in a place where I have no other tools to settle the question. If I don’t have—like, “the burden of proof is on the one who seeks to take from another.” Why is it important to check who currently has the money? What matters is to check who is right—was there a loan or wasn’t there a loan? Why does it matter who has the money right now? It matters a lot. Why? Because if you remain in doubt and have no decision whether there was or wasn’t a loan, where do you leave the money? With the person who already has it. The burden of proof is on the one who seeks to take. Right?

So it is very important to discover what the starting point is. What do I think? What would I have done if there were no proofs? Then I know that given a situation in which there is no objective proof and no way to settle it at all, I remain with my intuitive perceptions, and therefore it is very important for me to discover what they are, what my intuitive perceptions are. I don’t always know that. And now I’m going to propose various experiments that will try to reveal that. Each person is supposed to do this for himself. I don’t know how to prove something to you. Rather, I’m giving you a certain toolbox that you should use, each of you, standing in front of the mirror. And each person is supposed to discover for himself whether he believes in free choice or doesn’t believe in free choice.

And my claim is that once, after the whole course we went through, we reached the conclusion that there is no way to settle this question, reason says that a person should lean on what his initial intuition says. So if you discover that your initial intuition is that you do have free choice, then you remain with that position, and there is no reason to change it despite all the important professors in neuroscience who say you don’t. Because that is your intuition, and nobody has brought you evidence that you should change your position. And vice versa. Someone who thinks the world is deterministic and that we don’t have free choice will remain in his deterministic position, because there is no evidence that can force him to give that up.

Therefore this is extremely important, and in fact it is the last tool left for formulating a position: simply to discover what I myself think, where I myself really stand on this question.

Okay. Rabbi, I usually get my intuition wrong. Okay, so there you go, you have a wonderful intuition. Every time you think something, infer the opposite conclusion. Fine, that too is a good intuition—one that itself is not mistaken either. Well, that needs checking.

Alright, I’m asking: what does it help? What does it help that I know what my intuition is? If you have no trust in your intuition, then you shouldn’t have trust in anything. I don’t know what to answer you. So there, for free—you also won’t believe whatever I answer you. Because what can I do for you? I’ll show you that your intuition is good, but that itself is also intuition. You won’t believe it. There is no way to answer skepticism. Meaning, if you are a skeptic, then you are a skeptic. There’s nothing to do about it.

No, no—what I’m asking is, you know what, I’ll put it differently. Sometimes my intuition is right, sometimes it isn’t. Okay, but in a place where you have no other evidence at all, what do you assume about your intuition? Nothing. I don’t know whether it’s right or not. I assume that this is my intuition. I think you don’t—there, this is a wonderful example of a person who does not decode himself correctly. Because you yourself—I’m sure that you trust your intuition when you have no other evidence. Only if there is evidence that undermines the intuition do you say, okay, here it misled me.

For example, let’s take a mirage, okay? A person walks in the desert and suddenly sees an oasis there. He approaches and sees that it’s all dust and vanishes like a dream. It was a mirage. He goes back to where he was, and does he stop believing his eyes? Of course not. As long as I have no clear evidence, I continue going with my basic intuitions. Otherwise I have nothing—I simply can’t do anything, there is no point talking. What do you want me to tell you? Everything I tell you—after I convince you, you’ll say, “Yes, this convinced me, but who says it’s true? Maybe I was mistaken.” So what am I supposed to answer such a thing?

No, what I’m saying is: it’s not a way of clarifying, because I know that not all truth is with me. I didn’t say all truth. I said this is the starting point. Unless proven otherwise, this is my position. I didn’t say I am certainly right, and I didn’t say this is necessarily the truth. What I said is that if I have no objective tools, then intuition is the tool I use. The objective tools too, by the way, are an illusion. The objective tools themselves rely on all kinds of intuitions. Someone will bring you scientific proof. Who says that what the lab technician saw with his own eyes there in the experiment really happened? That too is intuition: to believe my eyes really reflect reality correctly. Who says that’s true? There is an intuition that it’s true. But maybe not? You can’t so much as move your lips if you start from such a skeptical point of departure. Again, this is not an answer. If you are a real skeptic, then you are a real skeptic—there’s nothing to do—but then I can’t help you. I’m speaking to people who are not troubled by this, people who are not skeptics. To skepticism I have nothing to answer. But of course then you’re not supposed to accept anything, not only in the area of free choice but in any area. You are simply supposed to remain skeptical about everything, except of course skepticism itself.

Okay, in any event, to our subject. The first thought experiment—actually the first experiments—I’m taking from a book by a friend of mine named Avshalom Elitzur. He wrote a book called Time and Consciousness, published by the Broadcast University series. Once we had a joint television panel on these issues of free choice. In any event, there in the book he tries to show the existence of a spiritual dimension in man. Again, he is not talking about libertarianism versus determinism, but about dualism versus materialism. Meaning, the question is whether there is something in us besides matter.

The experiment he proposes is the following. I’m talking now with a person and I say to him: “Listen, I have a proposal for you. I am now going to kill you in a way that of course won’t cause you any pain or suffering—a sleeping pill that will kill you after you fall asleep, and everything is fine. And I will build a creature that is completely identical to you, molecule by molecule, cell by cell. Absolutely identical, with all your memories, all your neurons in exactly the same state, your entire brain structure exactly identical, everything the same. Every fat molecule is located in the same place it was in your body. Everything is absolutely identical.” Of course this is a thought experiment; there isn’t much way to do it. But in principle, do you agree?

Now he assumes—and again, each person should check himself—that most people would not agree. Right? I assume most of us would agree with that assumption. But again, if someone comes and says, “Yes, I have no problem, I agree,” then fine, there’s nothing to say to him. That’s exactly the point of a thought experiment. A thought experiment doesn’t prove anything to you; it helps you discover what you yourself think.

Now I ask each of you to ask yourselves how you would answer such a proposal. If you would answer in the negative, then I ask: why not? Why do you refuse? What’s the problem? After all, I’m bringing back you yourself exactly as you were. Why do you care that there were a few minutes in which you were not alive? After a few minutes you return, everything is fine. What’s the problem? That you slept for a few minutes?

So what is he really trying to say? He is really trying to say that someone who answers this question in the negative is apparently assuming that the new person we create, who is completely materially identical, completely identical to the original person—that is not the same person. And therefore I don’t want them to kill me and create another person. How does that help me? Okay?

You know, what always comes to mind for me in this context is the example of a cursor on a computer. Yes, when you run a cursor on a computer—this is for DOS graduates, not Windows. Meaning, yes: when you run a cursor on a computer, it moves, say, from left to right. Okay? What does it mean that it moves? After all, it doesn’t move anywhere. I turn it off here and turn it on in the next spot, turn it off in the next spot and turn it on here, turn it off here and turn it on there, okay? And to the eye it looks as though it’s moving from left to right. But really nothing here is moving. I turned it off here and turned it on there, turned it off here and turned it on there. Nothing is moving along that axis. Things are switched off and on, off and on. That’s all. There is no actual movement along the axis. It seems to us that it moves.

Actually, the claim is that in our eyes the cursor seems to move from left to right because we think that the cursor when it is here is the same cursor that was there. It just moved from there to here. But it isn’t—it’s another one. That one we turned off, and this one we turned on—just the same thing, right? So since it is the same thing, as far as we are concerned the cursor moves. The cursor didn’t move anywhere. We turned that off and turned this on.

In physics too, in quantum theory, there is a formalism called second quantization. In field theory they use it. It describes motion through an operator—motion or change of properties, never mind—through what are called creation and annihilation operators. A given body suddenly receives additional momentum, say a higher velocity. I basically say: I destroy the previous body and build it with new momentum. Fine? Which from my point of view is as though the body accelerated. This is what it means to say the body accelerates, gets a higher velocity. Okay? This is basically that phenomenon. From a physical standpoint it is the same thing. Because in the particle I create exactly the same particle with a higher velocity. So what is the difference between that and saying the previous particle got a higher velocity?

Now I ask what your relation is to the same thing when it is directed at a person. Or a particle. Can I relate to a person as to a cursor? I say: I’ll kill you here, I’ll build you there—that just means you moved from the chair to the bed. That’s all. So those who would not agree to this experiment are apparently assuming that the person who will shortly be lying in the bed is not the person who is now sitting in the chair. It is another person.

Now I ask: in what way is he different? After all, all his cells, all his molecules, every little thing in that person is completely identical to the original person. So in what sense is it another person? Why is it another person? What’s the problem? Why do you have a problem with such an experiment? Why is it not okay? Apparently because you assume it is not the same person.

Now I ask: not the same person in what sense? What is there in that person that is not in this one, and vice versa? After all, the whole periphery—all the material dimension of these two people—is completely identical. That means there is apparently something more here besides all the atoms and molecules and cells. There is apparently something else missing, something found in me and not found in him, or vice versa. That is what we usually call soul or spirit. And if you do not think such a thing exists, if you think a human being is only a body, then in principle you should not refuse such an experiment.

More than that—you know what, let’s improve the experiment. I propose that I kill you in a very gentle and painless way, and rebuild you completely identically—and I’ll also put a million dollars in your bank account. Fine? Now there already is a difference between the old person and the new one: the new one has another million dollars in the bank. That’s it. Aside from that, it’s basically the same person—and the neuron that knows what the state of his bank account is, that too is different, because the previous one thought he had a million dollars in the bank, and the second one knows he has two million dollars. Okay? So there is something in his memory that is slightly different. But that’s all. Aside from that it’s the same person, just with another million dollars.

Do you object to my offering you to sleep for half a minute and wake up with another million dollars? I assume most people would agree to an experiment of that kind, right? I offer you to sleep—not to die—sleep for half a minute and afterward I’ll give you a million dollars for having slept half a minute. To that people would agree. Now what is different between this experiment and the previous one? The previous experiment doesn’t say sleep half a minute—I rebuild you, meaning you wake up, and you wake up with another million dollars. What’s bad about that? Why do you refuse it?

You know, I’ll tell you something even more extreme. You’re worried that maybe, maybe molecules—maybe if I build you… What? Question. There is the famous Talmudic passage about Rava and Rav Zeira, where he killed him and slaughtered him on Purim. Yes. At the Purim meal? Yes. I assume that when he brought him back it was the same person, it wasn’t… another person or something after that resurrection. Because there, again, I assume it never literally happened—it’s aggadah. But even if we take that aggadah as a factual description, what happened there, I assume in the sense I’m talking about, is that he took his soul and returned his own soul into him; the body remained exactly the same body. So that really is the same person.

But in the experiment I’m proposing there is no soul. There is a body, and I build the same body out of other materials. That’s all. If I were returning the same soul to him, then it’s obvious that it is the same person. That is indeed true. But that is exactly what Avshalom Elitzur claims: that people who answer this question in the negative assume that in a person there is something more besides a body—the soul. If you return that too, then I really am the same person. But if you only duplicate my material dimension, you have not created me; you have created someone else who is identical to me.

Now another proposal, the next experiment. What happens if now I don’t manufacture you, synthesize you in a lab—I dismantle and reassemble you yourself, out of your own cells? Meaning, I take you, completely dismantle the cells—if you want, the molecules—put them in jars around me, and now I build you back, synthesize you again in exactly the same order, each cell and each molecule in the exact place it was in the original body. This is no longer other materials; I’m not using other materials. I’m taking the original materials of your body. I dismantled you and assembled you back. Would you agree to that? And in addition, a million dollars.

Would you agree to that? I assume most people would not agree to that either. And again, not because they are worried I won’t succeed. I’m not talking about that. Assuming the technology exists, I will succeed. Fine? That isn’t the problem. Again, I assume—each person should ask himself—sure, somebody could tell me, right, I’d agree to it. Fine. But if a person doesn’t agree to it, then again I ask: why not? Why do you care? You’ll earn a million dollars. Why do you care that you slept a few minutes? And again the answer is apparently that the person thinks that even if you return all his molecules and cells, his own, in exactly the same way, still you have not brought him himself back to life; it will be someone else.

What does that mean? It basically means that there is probably in these bodies something more that determines that they are two different bodies beyond the whole material dimension, which is exactly the same. Meaning that in this thought experiment you have basically discovered that you believe in the existence of a soul. Because if you didn’t believe in that, you would presumably agree to the experiment.

And again I say: a thought experiment never proves anything to you. If a person comes and I offer him the proposal and he says, you know what, I agree, then really I can’t say anything to him. He agrees, and everything is fine. He is a true materialist. But if there is a person who declares himself a materialist, and now when I ask him this question—or when he asks himself this question; when I ask him it’s always an argument and he’ll try to win—I’m talking now about each person asking himself: what do you answer yourself? Leave me out of it, what do I have to do with it? Ask yourself and answer yourself, and by doing that check whether you really are a materialist or not.

And many people will thus discover that they are not really materialists, although they thought they were. This is a thought experiment that can help you discover that sometimes you do not really believe the things you think you believe. Sometimes through such a thought experiment you can discover what you really think. I think that’s not a bad example of such a thought experiment.

Now, just today cloning is not only imagination. Yes, true. With Dolly or something—with animals they’ve already done it. Cloning can be done. Right, except that in cloning it is something else, because there it really is producing a similar creature out of other materials. The genetics you take from the original creature, but the phenotype, the creature itself, of course comes from other materials. And beyond that, even in cloning there is no absolute identity. The genetics are identical. That doesn’t even mean the brain will be the same, because we have things besides genetics. Okay? I’m talking about duplicating you completely. Environment and genetics and everything the same, implanting in the brain the same memories, everything the same.

You understand—in Dolly the cloned sheep, she doesn’t have the same memories as the original sheep. We’re not duplicating the brain; at most we duplicate the structure of the brain, which comes from genetics, but the information stored in the brain, that we do not duplicate by genetic cloning. I’m talking about duplicating you completely. And again I say: for the moment this is a thought experiment, but in principle I see no reason why there couldn’t be a stage at which this could be done. In principle I think yes, this could at least be possible. There is sense in asking this question because it is not all that hypothetical. Today we don’t know how to do it, but there is no reason that at some stage they won’t know how to do it. In any case, this hypothetical question can reveal to us where we stand.

Here there is another important point. A person can come and say: I’m not convinced. I really don’t agree to this proposal, but I’m not convinced. Why? Because he basically says—and I’ll bring it by way of an interesting philosophical question—there is a principle laid down by Leibniz, the philosopher Gottfried Wilhelm Leibniz, which he calls the identity of indiscernibles. And his claim is the following: if there are two bodies that have exactly the same set of properties, then it is the same body itself; then they are not two, they are one. That’s what he claims.

Meaning, if you take two drops of water, fine, that have exactly the same shape, exactly the same properties, everything the same, then they are not two drops of water—they are one. It is the same drop. Think of the drops as also being in the same place, okay? Everything the same. Or if two identical drops are in different places, that’s two. Let’s say they are both also in the same place. In principle, the impossibility of being in the same place is a physical problem, not a logical one. So let us assume there is no such physical problem in some hypothetical world, and these two drops of water are also in the same place. Then he claims that this is the same object.

Now he brings a proof for this. He has a logical proof for the matter. The argument is this: let us assume not. Let us assume the contrary and see that it leads us to a contradiction. It is a proof by contradiction. How? Let us decide that we have two drops, two objects, that have exactly the same set of properties, but they are two. Meaning they are not the same object itself. Fine? They are two objects, each of which has exactly the same properties.

Now object A has the property that it is not object B. Because if they really are two and not one, then object A has the property that it is not B. And object B does not have that property, because it is B. So that means their set of properties is not identical, contrary to our assumption that they have an identical set of properties. Therefore it is obviously the same object itself—QED.

Now this sounds like some sort of philosophical hair-splitting, but if you try to think about it, it isn’t easy to put your finger on where the bug is here, where the mistake is. Now there is a mistake. Clearly he is not right, neither in the argument nor in the conclusion. I’m sure he is not right, and in my opinion two different objects can definitely exist—you see how this connects to our topic—two different objects can definitely exist with exactly the same set of properties.

Why? To understand where Leibniz’s argument falls, this is the antithesis. Against it he raises his own argument, okay? So first of all we understand what the two positions are here. Now my position, which says that two different objects can be identical in their properties or indiscernible in their properties—what does it actually assume? It assumes that the object is not only a collection of properties. Right? After all, what does Leibniz assume? Leibniz assumes there is nothing in an object besides its properties, right? And if it’s the same set of properties, then apparently it’s the same object.

I, by contrast, assume that there is something more in the object besides its properties. And I would say even more than that: the object is not the properties at all. The properties are its properties. There is someone who has the properties. The bearer of the properties—that is the object. When I ask, I don’t know, who is this person? Is this person his kindness and his intelligence and his tendencies and his talents and his height and his weight and all that—is that the person? No. Those are properties of the person. So now I ask: who is the person? Who is the bearer of the properties? Whose properties are these properties? And here I say: obviously there exists some abstract object of some kind, and these properties are its properties.

Therefore I say that if there are two such abstract objects, and they are two, other—not different. They are not different in properties, they are identical. But they are other; they are not one, they are two. Okay? So there is no obstacle to their having exactly the same set of properties, these two objects. That is the dispute.

Now if you go over Leibniz’s argument and see why it fails, after we have properly presented the opposing position against which he is arguing, you’ll see why his argument fails. What did he assume? He assumed that object A has the property that it is not object B. Who said that not being object B is a property? Leibniz assumes that all there is in an object is properties; there is nothing besides properties. So therefore, from Leibniz’s point of view, even the fact that it is not B is a property. But I think that the object as such is not the properties; the object is the bearer of the properties. The properties characterize the object. Therefore now I say that when I say A is not B, I have not pointed to one of its properties. On the contrary, I have pointed to the object itself and said: it is other. So that does not mean it has some other property. Their set of properties is identical, and otherness is not a property. Otherness concerns the object and not its properties, the object as such and not its properties. Okay? And therefore Leibniz’s argument fails.

For our purposes, what this basically means is that the materialist can come and tell me: look, I refuse the experiment. Why? Because it may be that you restore all my properties to me, but that still won’t be me. I am the bearer of the properties; I am not the collection of properties itself. And that doesn’t mean there is a soul or spirit. It only means that even in the material whole, even in material objects, the bearer of the properties is something else; it is not merely the collection of properties. How will you reconstruct the object and not its properties? After all, you build for me another object with the same properties, but it is another object; it is not me. Okay? That is the claim.

Here there is room for hesitation. I’m not entirely sure whether this claim really holds water or not. I’ll tell you why I’m a little suspicious of it. This claim can hold water regarding the first experiment, where I proposed building you out of other materials. But if I dismantle and rebuild you yourself from the same molecules and cells that I took from you—I dismantle and reassemble them, fine?—in exactly the same form as before, to say that here another object was created with the same properties—in what sense is it another? What is there in it that was not in the previous one, or vice versa? I don’t see the philosophical logic in that statement unless you assume that there is something called a soul besides the body. Otherwise I don’t understand it. After all, it is exactly the same thing. It isn’t just the properties; I also built the same molecules, the same cells. The properties are a derivative, so it also has the same properties. But first of all it is the same body, the same thing itself. So in what sense is it not you? I think that’s still true only if you really believe in the existence of spirit or soul or something of that kind.

Think of a glass of water. Fine? I take molecule by molecule of water out of the glass, put each one in a different place, then return all the molecules back into the glass. Okay? Is that the same water that was here? Of course it is. Even though water is a collective entity, a collection of molecules, not each molecule separately. Right? Fine, but a collection of the same molecules will also yield the same collective entity. I’m choosing this example deliberately—what about the continuity of the object? Meaning, that there is some break in the continuity of the object in that same experiment. So maybe there is something in continuity that makes it the same thing, something along the axis of time. No, but then you… I’ll get to a question in a moment that I think is this question, okay? If not, stop me, but I think it’s this one.

Fine. Let me now propose a third experiment. The third experiment basically says: after all, in us ourselves as human beings, our cells are constantly being replaced. I don’t remember the figure right now, but after not so many years, not a single cell remains in us that was in the original body. We have been completely replaced. So in fact these experiments I described earlier happen—they actually happen all the time. And still I relate to this body as though it is the same person as before, even though nothing in it already belongs to what was there before.

This recalls the example in Greek philosophy called the Ship of Theseus. Yes, Theseus king of Thebes took his ship, it was damaged in a storm. He took it to the dock at the harbor in order to repair it, and they replaced the wood and so on, he sailed again, then again there was a storm. He returned to the dock, they removed the damaged wood, put in new wood. At some stage there is no longer any wood left from the original ship. Is this the same ship? Is this still the ship of Theseus? The ship of Theseus in the original sense. It belongs to Theseus in terms of ownership, yes, but is it the same ship?

By the way, this is a halakhic question. A halakhic question—Ritva and Tosafot discuss what happens if someone vows never to enter his father’s house, or gives his wife a bill of divorce on condition that you never go to your father’s house, and the house fell and the father rebuilt the house. Is she allowed to enter that house? In other words, the question is whether it is the same house as before or not. This is a dispute between Tosafot and Ritva and others; we won’t go into it here. So these are existential questions, and in principle one can ask them. With us, this actually happens.

There have been, for example, all kinds of gerontological projects, yes, to create—to extend life and create eternal life. Well, it is obvious that creating eternal life means taking care of the body so that it will manage to replace all its cells and still remain functioning, and then replace them again and still remain functioning. There is some gerontologist named de Grey—there’s a whole controversy around him, never mind—he does all kinds of experiments on hydra, those creatures that have some property, they live half a year I think, they’re some kind of jellyfish-like creatures that live half a year, and he managed to get such creatures to live ten years already. How does he do it? They have some mechanism that reverses the time axis. Meaning, they grow and grow for half a year; after half a year there’s some hunger cycle, so he shrinks them back to being, I don’t know what, the original creature, the original larval form, I don’t remember what it’s called, and grows them again, so he gave them another half-year. Again they shrink, and again grow for half a year. Of course all the cells are replaced. He is basically creating pulses of regrowth of the person. He basically returns me to childhood and grows me again—there, he gave me another eighty years. And so on. He’ll keep returning me back and forth like that, and that’s how he extends life. In principle, eternal life.

These are very nice debates in scientific journals, and no one has really managed to show the infeasibility of his project, even though they were furious at him and said it’s also immoral, never mind. There is a project here to do this for human beings. But the journals issued warnings, and whoever succeeded in showing what is problematic about this project and what is impossible about it—no one succeeded. And in the end no one got the prize, because they had offered a prize to whoever would show it.

So the point is that such a project might exist. Now the interesting question is: in what sense will the person of another thousand years be myself? Why should we try to extend our lifespan? After all, we’re working for someone else. That someone else who will live here in another five hundred years—all his cells are different, he will also lose the memories; after five hundred years I assume we won’t remember much, because otherwise our brain would totally clog up, so it loses memories. So in the end, what will remain? So in what sense is life extension an aspiration for human beings? Extending life is just replacing yourself with another person and another one every eighty years. That is what happens to us now. Even now, after eighty years—or ninety or a hundred, may all of us live long—the person dies and a new person is created. What would gerontology do that does not already exist today?

You understand that all these things point to there being in us, in the human being, some dimension beyond the matter in us. Otherwise it is hard to explain why we relate to—here I return to what Daniel asked earlier about continuity of identity, okay, the persistence of existence. And that is exactly the point. In what way, as we continue, continue all the time in time…

Adi Tsemach once wrote an article in which he tries to explain our moral commitment to others by asking: why care about myself? When I care about myself, I’m actually caring about myself, say, for retirement. When I retire, I’m caring about myself, I’m saving a pension so I’ll be able to live reasonably. He asks: what do you mean? When you’re retired that will be someone else. Why should you care about that other person? Oh, you care about another person, so care about other people too. Meaning, you should really be morally committed to every person, because there is no difference between you in another ten years and your neighbor today. One is along the axis of time and one is along the axis of space.

Now of course I’m not speaking on that plane. I’m speaking now about the fact that even if cells are replaced or all kinds of things like that happen, the identity continues. Is that really still me myself? So it’s obvious to us that yes. In what sense? Because there is probably in us something more besides biology. And the new person, I can in principle put into his brain all the memories I had. That isn’t the problem of differences in memories and skills. I’ll teach him the skills, I’ll implant the memories, and everything will be fine.

Maybe one more thing in this context, and then I’ll finish with another interesting thought experiment. Another interesting point is that from time to time some article appears in the press, mainly the popular press, though it starts from scientific journals. I brought in the book some example from a sensationalist article in Haaretz showing that sperm cells have mathematical ability. Because sperm cells compute some trajectory by means of calculating complicated derivatives and things like that, and he says they do it in tenths of a second. The most intelligent human beings in the world can’t do such a calculation except maybe in hours or more. Meaning that sperm cells are smarter than the greatest mathematicians or physicists or whoever you want.

Now I didn’t know whether to laugh or cry when I read this. It’s just such nonsense. Usually in popular science literature there is truly wild nonsense. I mean, I want to hope it’s only the popular journalist and not the scientists who wrote the original article, because I didn’t read it. But it’s always awful. Reading popular science columns is awful. It’s simply because it’s always sensational, and the sensational part is always the false part. The non-sensational dimension is the scientific result, and in order to get it into the popular press they make some sensation out of it, and the sensation is always false. Anyone who knows the field knows that in the academic world, your greatest achievement is that an article about you gets published in Maariv or Yediot. Much more than in the most prestigious scientific journals. Because then it means you have some meaningful achievement worth mentioning to the general public. And honestly, it’s really like that.

When I was at Bar-Ilan, for example, in physics, on the bulletin board they were always posting newspaper clippings there—popular newspapers, Maariv, Yediot, Haaretz, whatever—popular press reports on things members of the department had done. They didn’t post articles from Nature, or articles from scientific journals like PRL, Physical Review Letters, which is now the most important journal in physics. They posted things from Yediot and Maariv and Haaretz, because in a certain sense that really is an indication—it means it’s a significant enough achievement to be put also in the popular press. But in order to reach that achievement, scientists go to journalists and convince them that there is some philosophical sensation here, not just an interesting scientific result, and it’s always nonsense. Almost always. It’s simply nonsense. They sell him something banal and show him that it supposedly has very dramatic meaning, and that’s how he’s convinced to publish it in Haaretz or Yediot or whatever.

Alright, for our purposes: what’s the problem here? The problem is that if you relate to it this way, then water has the intellectual ability of the greatest physicists. And it solves the Navier–Stokes equations. I already mentioned this example—very complicated equations that people don’t know how to solve. You said that’s your project, right? So very intelligent people don’t really know how to solve these equations except in simple cases. Very simple ones, even. Turbulence—no one knows exactly what it is. What is turbulence? Yes, right. So that isn’t exactly known, and water knows. Yes, exactly. Meaning this is an example of a hydrodynamic phenomenon that water solves easily. It knows how to flow, it solves the equation, and we, all the greatest physicists and greatest mathematicians, don’t know how to solve it except in the simplest cases in the world. So what does that mean? That water is more intelligent than mathematicians and physicists? That’s nonsense.

What is there in sperm cells that water doesn’t have? Nothing. The model we make in order to describe the action of water or sperm cells is a mathematical model. They do not solve mathematical equations. In order to be intelligent, you need to be someone who makes judgments and calculations and things like that, not someone who carries them out in practice. When a bird navigates, that is not intelligence. When a bird navigates, it is inborn in it, and it does what is inborn in it. Intelligence is a person who builds a device that knows how to navigate on the basis of theoretical principles. Because then he has revealed intelligence here.

By the way, in the world of artificial intelligence they do not recognize this distinction. That’s where this comes from. In the world of artificial intelligence, they measure the intelligence of a computer, of a bird, of water, and of sperm cells. So from their point of view, if you know how to carry out complicated tasks, you are intelligent, and the more complicated the task, the higher your intelligence. And I think, fine, at the scientific level you can define it that way too. It doesn’t bother me if that’s convenient for scientific research. But at the philosophical level that is complete nonsense. No computer has intelligence and no bird has intelligence. It simply isn’t relevant. After all, intelligence belongs only to the human beings who built the computer, or who make a simulation of the bird or of sperm cells or whatever, because they are genuinely exercising talent. Someone who has no talent doesn’t know how to do that. But the bird doesn’t need talent to do it; it’s simply inborn in it. Just as the computer doesn’t need talent to do its calculations; the programmer simply put it into it, or its builder—software and hardware together.

Therefore I say again, even statements of this kind—when you suddenly understand why this is problematic, like the Turing test, another thought experiment here in our series. The Turing test basically says—the test Turing proposed, you know what, maybe I’ll end just with this and do something else next time, because this is indeed another thought experiment I didn’t have time for.

The Turing test—Turing proposed a test, the Turing test. Turing proposed a test to know when a computer, when one can relate to a machine as a person, to artificial intelligence as though it were a person. So he proposed the following test. Say you are conducting a conversation with a creature located in a room. You do not see it. What you receive from it are written messages. Fine? Messages come out on your printer, and you send it messages by email, and it answers you back by email, and so on. You conduct a dialogue with it, ask it a question, it gives you an answer, and so on. Okay?

How can you know when it is a person? When you see that it answers appropriately, meaning that you ask a question and it gives a relevant answer. It may agree, it may disagree, but you understand that this is an intelligent answer. Then you understand that behind that wall there is a person.

Now let us assume they put a computer with artificial intelligence in one room and a person in another room. And you send both of them questions and they send back answers, and you conduct a conversation with them. Now I ask you: in which room is the person sitting, and in which room is the computer sitting? On the day a computer is created such that we cannot distinguish who is the person and who is the computer, then one should relate to that computer as though it were a person. That is what Turing argued.

So this is the test Turing proposes, a phenomenological test. The test Turing proposes for the point at which this intelligence of the computer can already be treated as though it were a person. Yes, whoever saw the movie Her, about someone who fell in love with his computer, with the software of his computer—that basically expresses this idea. He carried on an intelligent conversation with his computer and simply fell in love with the creature the way one falls in love. By the way, this is not at all far-fetched. When you fall in love with someone over the internet, you have never seen them, only corresponded with them, and you talk meaningfully, and suddenly you fall in love with the person, with his personality, his answers, his way of thinking. You may not meet him at all. There are couples today who are formed without seeing each other. Today on the internet you can also send pictures, but I’m saying in principle you don’t need that. There can be falling in love with a being through my correspondence with him.

Therefore this thing, that the person falls in love with his computer, is not far-fetched at all, in that movie. Because his computer spoke to him intelligently, showed him a fascinating personality, gave him answers that spoke to him, and he saw that it had a personality suited to him in some sense. He fell in love with that personality. Okay? And the claim is that this passes the Turing test, and therefore this computer has the rights of a person; one should relate to it morally; it has in fact become a person, this computer. That was Turing’s claim.

Now today we are already getting close to that. There are computers that took the Turing test against a child of, I think, thirteen, something like that, and it passed the test. Meaning, with a computer versus a thirteen-year-old child, an ordinary person no longer managed to distinguish which was the computer and which was the child. This means we are already approaching a state in which artificial intelligence will manage to convince us that it is a person, will pass the Turing test.

And the question is: is Turing really right? If, say, there is software that passes the Turing test, is it really a person? Should we really relate to it in the same way we relate to a person? Now people will tell you: look, but it is made of metal and wires and things like that. So what? Does a person deserve rights because he is made of organic material? An elephant is also made of organic material. Should one relate to an elephant in the same way as to a person? One should relate to it properly, but should one relate to it like a person? I assume most of us would agree not. The fact that you are made of organic material is uninteresting. So what does matter? What is missing?

Again, this is the same thought experiment I spoke about earlier. My thought experiment is whether you accept the Turing test. And I think that most human beings in the world, even though in artificial intelligence this is very accepted among many people in that field, most human beings will not accept that test as a test for the software being a person. And that itself is another thought experiment in the series I’m proposing. If you do not accept it, that means that for you a person is not computational abilities, or not even interesting interactions or things of that sort. There is something in the one who is interacting with you—in the personality, in the human being, in the entity itself—without which it is not a person. Without that, it is a computer behaving as though it were intelligent. It is not intelligent; intelligent like water and like a bird, but it behaves as though it were intelligent. Fine? Because its programmer was intelligent.

This means that I do not accept the Turing test at all. The Turing test is the same failure as this whole series of thought experiments I described here. Because it too basically describes the person as a collection of his functions. But that is not true. A person is not a collection of functions; the person is the bearer of the functions. And if I produce all those functions in another creature that is not a person, that will not turn it into a person—exactly as when I duplicate the… here it is a person, but not the same person, rather another person. Okay? All these experiments lead to the same place.

And this is supposed to convince us—whoever answers no to all these experiments—it is supposed to convince him that he thinks there is in us something beyond matter. We have a soul, spirit, or something like that, and this is in fact the essential component in the definition of a human being. Whoever answers yes to all these things—fine, he is a materialist, and fair enough.

And notice—I’ll just finish by saying that all the experiments I described here are meant to examine the question of materialism, not the question of determinism. Because for the moment I’m only checking what the person thinks—or giving you tools for each of you to check yourselves—what you think about the question of materialism: is the human being only his matter, or is there something more in a person? And as I’ve already said more than once, you can be a dualist, believe that there is matter and soul or spirit, believe that there is body and soul, and still be a determinist. You can assume that the soul too operates deterministically. Dualism is a condition for a libertarian worldview, a worldview that believes in free will, but it is not sufficient. Meaning, you can be a dualist without being a libertarian. You can be a deterministic dualist. But you cannot be a libertarian—I think you cannot be a libertarian without being a dualist. Because within physics you cannot fit in free choice, as I said earlier. So in order to say that there is free choice, there has to be something more besides physics. Therefore dualism does not entail libertarianism; libertarianism entails dualism. Okay? That is my claim.

So all the experiments I have described up to now are experiments that are meant to help us check our position regarding materialism, not regarding determinism. Is there in a human being something more besides matter? Next time I want to do one more thought experiment that examines the question whether we have choice—not only whether we have a soul. Free choice, the question of determinism. Okay?

Alright, and next time I really will finish this scientific series, let’s call it, this scientific-philosophical series. Alright, that’s it so far. Rabbi? Yes. Artificial intelligence—is the claim basically that there is no such thing as intelligence, that the computer cannot understand? Artificial intelligence is semantics; I wouldn’t call it intelligence. Intelligence is a property of a being that has judgment, that can decide which tools to use and what to do. A computer has no judgment, including the most sophisticated computer that exists. So the claim is basically that there is no such thing as artificial intelligence. Correct. There is statistics, there is skill in problem-solving, programmed skill, but the intelligence behind it is the programmer’s intelligence, not the computer’s.

Again, sometimes the computer can do things that its programmer himself does not know how to do. That doesn’t mean anything. Its programmer built a machine that can manage to do things for him that he himself can’t manage. It is still the intelligence of the programmer. Just as a person builds a car and thus reaches a speed of a hundred kilometers per hour. So what does that mean? That the person has the ability to reach a hundred kilometers an hour? On his own he couldn’t do that without the car, but he has the wisdom to build a car that will take him at a hundred kilometers an hour. Same thing with artificial intelligence.

Yes, I’m saying intelligence means understanding one thing from another, and that is something a computer cannot do. Understanding—not necessarily one thing from another, but understanding. A computer understands nothing. A computer has no consciousness. It understands nothing. A computer does things, moves electrons from place to place, that’s all. Maybe I’ll sharpen that a bit next time as well, because it really is a point that needs a little sharpening. There is a reverse Turing test—artificial intelligence that identifies who the reasonable human being is. Okay, but that intelligence still is not a human being. Yes. You know, it’s like the reverse responsa project. My son once wanted to build a reverse responsa project. The regular responsa project says: what is the view of Rashba on, I don’t know, heating water in a secondary vessel? Fine? And he wanted to build the reverse responsa project: who is the halakhic decisor who permits heating water in a secondary vessel? And the responsa project will output Rashba, Maimonides, Ran, or whoever, Mishnah Berurah, whoever it may be, because you are basically searching for who will permit it for you. You’re not searching for what Rashba’s opinion is. The reverse responsa project basically does that operation.

Alright then, Sabbath peace to all of us, goodbye. More power to you, Sabbath peace, thank you very much.