Robert Nozick’s Final Interview

Julian Sanchez: It seems as though the ethical view you put forward Invariances (2001), with its emphasis on evolution, is quite distinct from what underlies a lot of the discussion in Anarchy, State and Utopia (1974), where there seemed to be something of a Kantian flavor to the argument, or in Philosophical Explanations (1981), where you talk about the value of organic unity. Is this as drastic a change as it seems?

Robert Nozick: Well, it’s hard to make progress on philosophical topics. A lot of them seem to have been intractable. So one faces a choice between adding a wrinkle to a view you yourself (or someone else) have developed, that hasn’t quite gotten all the way, or trying an approach from a new angle that might illuminate something else about some other aspect of ethics, whether or not it gets all the way. I guess my tendency is to think essentially that the new wrinkles won’t do the job if the old major idea didn’t, and so you have to try something different. Then maybe they can all be combined in some coherent piece.

JS: So your hope is that eventually some of these apparently very different perspectives may end up shedding light on some area of overlap?

RN: It would be nice, but I can’t say my prediction is that that’ll happen. We have to see what the relationship is between these different things. Certainly the emphasis I place in this chapter on coordination of behavior and cooperation to mutual benefit is something that ought to be very congenial to people in the libertarian tradition.

JS: You outline a series of different “levels of ethics,” as you call them, the most basic being characterized by, as you said, “voluntary cooperation for mutual benefit,” and the higher levels involving more responsiveness and caring for others and positive aid. Yet you say, and this is what seems particularly libertarian, that no society should go further than enforcing that most basic requirement of peaceful cooperation.

RN: Yes, and libertarianism never really claimed that all of ethics was exhausted by what could be enforced, by what one could legitimately be coerced to do or not do. That’s the political, interpersonal realm that libertarian principles were about, not what might be the highest ethical aspiration.

JS: What is it about that most basic level then that makes it most uniquely appropriate to be enforced?

RN: Well, it’s the most important level, I think, and if you try to enforce more than that, you’re truncating that level. You’re showing lack of respect for the voluntary choices of people, and interfering with them in coercive ways. We all benefit from the existence of that free domain of autonomous action, even when (as Hayek pointed out) we do not choose to (or are unable to) make use of those particular such freedoms ourselves. It’s the level that allows us each to live our own chosen lives. But I notice not everyone agrees with the primary importance of that level, and I try to account for how they don’t.

My little theory there, what I call the “principle of proportional ranking”, is that everybody thinks it’s the most important thing that ought to be enforced, and that there are different views of importance playing a role, between what the libertarian considers most important and what the welfare-​state, non-​classical liberal considers most important.

JS: A lot of people, [liberal philosopher] Thomas Nagel, for one, have been very vocally opposed to attempts to mix morality and biology. They believe that it expresses, in some sense, a failure to take ethics seriously as a separate subject matter. You clearly disagree.

RN: Yes.

JS: What is it, then, that evolution can tell us about ethics? Why should an evolved moral sentiment be any more normatively binding than, say, the urge to reproduce? Does explaining ethics as one more biological response suck out the normative force, the authority of morality?

RN: Well, there are two places where I discuss that in detail. I refer to literature in the Kantian ethical tradition that’s wanting a certain strength of bindingness to ethics -- including writing by my colleague Christine Korsgaard. I doubt that they can get it, and I argue that they’re requiring something stronger of ethics than we have in the case of ordinary factual belief. A comparable question to that of the bindingness of ethics -- “Why should I always do what’s right?” -- is “Why should I believe the truth?” In general it’s a good policy to believe the truth, but in particular cases someone might actually be better off not believing what’s true.

Examples one finds in the philosophical literature are somebody who’s seen the trial of a child of theirs, where they’re being proved guilty of some crime that would drive the parent into a depression, maybe a suicidal depression. They’d be better off not being convinced by this evidence. Or the literature that seems to show that optimistic or even overly optimistic attitudes towards one’s chances at succeeding at something, or recovering from a disease, or something like that, actually increase the chances. Maybe not up to the level of optimism one feels, but there one would be better off not being a perfectly accurate assessor of chances. In fact there’s some psychological literature that seems to indicate that when people are asked by psychologists what other people in their social circle think of them, and then the psychologists check with these other people about what they actually do think, that the people who have more accurate views of what other people think of them are less happy, less successful in life, cope less well with various things, than the people who have rosier views of what people think of them than is actually the case. Now, here’s another case where one may be better off believing what’s not strictly true. Parents raising children might think: “Well, do I want my child to have a disposition to believe exactly what’s true about other people’s opinions of him or her? Or to have, not an out-​of-​touch- with-​reality view, but a more optimistic than is actual view, a rosier view, of what people think of them, so that their life will go smoother, more easily, and so on?”

Now, there’s at least a question there. And in the case of factual truth, there’s not any knockdown argument, in a particular case where one would be better off believing what’s not strictly speaking true, for saying that a person is epistemically required to believe the truth. If we can’t do that in the factual case, why would we expect to do, and think we have to do, the comparable thing in the ethical case? That is: have a notion of bindingness so strong that in every possible situation, it requires one to do what in general is to our benefit and right, and what we’ve been shaped generally to do, including to be reasonably cooperative agents in social cooperation. Through the evolutionary process, those who are able to engage in social cooperation of various sorts do better in survival and reproduction. So I’m questioning the demand for bindingness in ethics. One, because nobody’s delivered on that demand yet, and secondly, even outside of ethics nobody’s delivered on the comparable demand.

JS: Which does seem to take some of the wind out of the objection? and yet we don’t want ethical conclusions to just be these sort of interesting facts.

RN: Correct. I search around for something that is more binding than merely an interesting fact. I do say that self consciousness is something that’s crucial to guiding one’s behavior in an ethical way, at least according to norms and principles, and that self- consciousness is something that people often take as the distinguishing mark of being human. Maybe in that realm, if the distinguishing mark of being human is something we’ve come to have because of its usefulness in having us adhere to norms, that is enough of a punch behind bindingness to leave us in a satisfactory situation.

JS: At the risk of asking something so counterfactual it’s not useful? does the emphasis there on the historical source of consciousness as something selected by evolution for this purpose mean that, say, my Swampman counterpart [i.e. an exact duplicate of me who springs into existence by chance, not through an evolutionary process], who arises as a mere fluke, has no reason to be moral?

RN: Well? there’d be all of the general reasons that we have for being moral in a society where we’re not good at deceiving others and others can detect when we’re being hypocrites. But is there some desert island case where somebody can get away with things and those reasons don’t apply? Yes. The strongest kinds of argument people make when you look in the Kantian literature seem to have something to do with preserving one’s own identity, or something like that. But that’s presupposing a concern with one’s identity. Why should one be so concerned about that? And if one is so concerned about one’s personal identity and integrity and keeping that identity, it’s hard to reconcile that with the strong attack on self-​interested motives that the Kantians mount. To say that self-​interested motives are insufficient to ground the normative force of ethics, but somehow it’s based on a concern with one’s own identity? that’s an uncomfortable position, a position in tension.

JS:Invariances contains quite a bit of science, from quantum mechanics to biology, and it seems that’s something you don’t very often see in a book of philosophy. At one point I think you even refer to superstring theory as an “interesting branch of metaphysics.” This seems to indicate a somewhat unusual view about the relationship between science and philosophy, or at least metaphysics. Is that right?

RN: Well, I think that science, as it probes realms that aren’t just at the level of ordinary macroscopic objects that we look at, uncovers strange phenomena, unusual and surprising phenomena that we didn’t expect that leads the scientist to formulate radically new theories about what’s going on. And those are conceptually very interesting, and philosophers ought to be interested in other conceptual possibilities, especially when there’s some reason to think that they might be actualities and not just possibilities. The scientists often have more unfettered imaginations than current philosophers do. Relativity theory came as a complete surprise to philosophers, and so did quantum mechanics, and so did other things. So I think that scientific theories are of great philosophical interest, and that they stimulate the philosophical imagination and mind. And they tend to undercut some of the traditional categories that we take for granted.

JS: One of the things you observe in the book is that claims of metaphysical necessity have had to make a pretty steady retreat in the face of the discoveries of science. Could it be that one day we would find that the philosophers would be helping the scientists, say by helping to spin out novel hypotheses for testing?

RN: Yes. I think philosophers can do things akin to theoretical scientists, in that, having read about empirical data, they too can think of what hypotheses and theories might account for that data. So there’s a continuity between philosophy and science in that way. In the Harvard department where, as you know, Quine raised famous doubts about the analytic/​synthetic distinction, it’s a commonplace that it’s hard to draw a sharp line between theoretical science and abstract philosophy. Abstract philosophy is impoverished when it tries to be wholly a priori, and theoretical science isn’t driven solely by empirical data. There are places where they can fit together quite nicely.

JS: So your approach to philosophical problems is less focused on pure deduction from first premises?

RN: The methodology of the book does not require proofs all along, but is more interested in speculation, in pursuing interesting ideas without trying to demonstrate that they’re true, as long as they stay philosophically interesting.

JS: This is a continuation of the method you set out in Philosophical Explanations.

RN: That’s right. It is, from another angle, an attack on requiring proof in philosophy. And it’s also the case, I guess, that my temperament is to like interesting, new, bold ideas, and to try and generate them. That’s a significant part of what excites me about philosophy, in contrast to those people whose main motivation seems to be to exclude certain ideas, or even most ideas. They seem to want to be thought police. That’s why, when these interesting conceptual ideas arise in the sciences, I think that they’re continuous with philosophical ideas. They’re interesting in the same way, shattering preconceptions. Surely some part of the appeal to libertarians of libertarian ideas is their boldness and unexpectedness. They’re surprising, and yet, one can grow comfortable with them very quickly. At least, some of us can.

JS: Which of the ideas in Invariances excited you most?

RN: I think the one that gave me the greatest excitement was the explanation I offer on the basis of evolutionary cosmology of why there are objective worlds. I have this chapter on objectivity, where I distinguish objective facts from objective beliefs and judgments. An objective fact is one that’s invariant under specified transformations, and under a wide range of transformations, the model of that being: things that are invariant in special relativity under Lorenz transformations are thought of by physicists as more objective than what’s not invariant under those transformations. (And an objective belief or judgment is one that is formed and maintained by a process in which the factors that tend to lead one away from the truth, biasing factors, do not play a significant role.)

Evolutionary cosmology formulates theories in which a universe is capable of giving rise to and generating future universes out of itself, within black holes or whatever. Would certain kinds of universes tend to generate more offspring and grand-​offspring, so that we would expect that eventually most or almost all existing universes would have a particular character? If so, that might constitute a (statistical) explanation of why our universe has the character it does?

I came to see scientific laws of the universe as something like the genetic constitution of the universe. If these universes were going to evolve and give rise to a large number of things, these features like the scientific laws would have to have a high degree of heritability. Meaning that whatever changes were made as a universe gave birth to an offspring, to use that biological language, the offspring would have to have the same feature as the parent universe, which meant that that feature was invariant under the transformation involved in giving rise to a new universe, whatever that transformation was, and whatever differences it made. So you would expect evolutionary cosmology, as certain types of universes were selected for, to give rise to universes that had scientific laws that were invariant under a wide range of transformations. That is (according to the theory I presented of what objectiveness consists in) it would give rise to objective worlds. This feature, to use biological language, would move to fixation in the population of universes, and you’d expect that universes would be -- the vast majority of them, on this model -- objective worlds, in the sense of having scientific laws that were invariant under a wide range of transformations. That connection between evolutionary cosmology and the theory of objectivity that I was formulating pleased and excited me a lot.

JS: Many libertarians know Karl Popper for his book The Open Society and Its Enemies , and you discuss some of Popper’s ideas about scientific method in Invariances.

RN: The book contains a page on Karl Popper’s philosophy of science, and a new argument against his anti-​inductivism. Popper is famous for saying that induction can’t be justified, that the only inferences that data support are to deductive consequences of the data, and that by deducing some observational consequences of the hypotheses and checking to see if these hold, we test hypotheses, but we never have reasons for thinking that a hypothesis that has passed tests in the past will continue to pass those tests. We have no more reason for thinking it will than that it won’t, or than that some other heretofore untested hypothesis will pass its future tests. Yet Popper does believe in the standard practice of testing hypotheses in a wide variety of circumstances. The degree of corroboration of hypotheses, according to Popper, is a historical statement about how severely that hypothesis has been tested.

There is no justifiable prediction about how the hypothesis will hold up in the future; its degree of corroboration simply is a historical statement describing how severely the hypothesis has been tested in the past. That’s Popper’s view.

What hadn’t been realized in the literature until now is that merely to describe how severely something has been tested in the past itself embodies inductive assumptions, even as a statement about the past. Of course, Popper accepts the usual methodological maxims about testing. Testing a hypothesis in a variety of circumstances or under a variety of conditions constitutes a more severe testing than simply repeating the same type of test under very similar conditions. Suppose I look at a certain type of case: the color of animals of a certain sort in a geographical area. The hypothesis is that all animals of this sort have the same color. You say, “OK, let’s check it again,” and I look in the same place for another animal of the same species. You say, “Let’s check it again,” and I look in the same place. You say, “Let’s check it somewhere else. ” And I say, “Why?” A severe test is checking something in an area or arena where, if the hypothesis is false, it’s most likely to show its falsity, given your background beliefs. The fact that we don’t keep repeating tests in the same arena is not because the probability of the hypothesis showing its falsity in other arenas goes up after it has passed tests in one arena. It’s that the probability of its showing its falsity in that arena goes down after it’s been tested there. If that didn’t happen, then the severest test would continue to be in the same arena.

JS: There would be no reason to do a wider range of tests.

RN: Right. So in describing how severely something has been tested in the past, we’re already assuming, in assessing that degree of severity, that the probability of a hypothesis changes on the basis of its passing tests. The probability of its being falsified in an arena changes, it gets lessened, on the basis of its already having passed some tests in that arena.

JS: So is this a reason to feel more optimistic about our ability to learn facts about the world, or a reason to become doubtful about the existing methodology?

RN: Well, it’s a reason for thinking that Popper’s theory is incoherent. Before, everybody said, “These are crazy consequences, that we have no more reason to think if we jump out the window that we’ll fall down rather than float up,” or something like that. Popper’s anti-​inductive conclusions were always held to be counterintuitive, even ridiculous, but he swallowed them, and so did his followers. Now I’m saying something stronger than has been said thus far, namely, that their view is incoherent. They can’t maintain the combination of views they do: that degree of corroboration is a measure of degree of severity of past tests (that have been passed), that you have to have varied tests, and that there’s no inductive conclusion that one can ever reach.

JS: So having already bitten one bullet, the question is which they’ll choose to chomp on next?

RN: Yes. I don’t know which part of the combination they will choose to give up, but they will have to give up one of them.

JS: Most of Invariancesis asking, in one way or another, “What is truth?” In exploring how we come to know truth, and what sorts of truth we have access to, you seem to make relatively modest claims about the kinds of knowledge, and the kind of certainty, we can hope for.

RN: Evolution plays a large role in my discussion of necessary truths and metaphysical truths, and I ask “why would evolution have endowed us with such powerful cognitive capacities to know about all possibilities?” Maybe evolution just gives us ‘good enough’ theories like Euclidean geometry that are approximately true and able to get us around the world, but when we probe further we discover that they’re not strictly speaking accurate. That question about cognitive capacity connects up with one segment of the libertarian movement: that influenced greatly by Ayn Rand, that has axioms like the law of identity, “A is A” and all that, from which they think conclusions follow that most people, elsewhere in philosophy, don’t think follow from these logical truths. I take evolution very seriously, and think that the capacities we have, including of apprehending a truth, have been strongly shaped, not to mention created, by evolution. So you could ask: “Why, then, do we have such powerful capacities as to give us these necessary truths, rather than truths that hold roughly and approximately at the actual world, and in similar worlds. The followers of Rand, for example, treat “A is A” not just as “everything is identical to itself” but as a kind of statement about essences and the limits of things. “A is A, and it can’t be anything else, and once it’s A today, it can’t change its spots tomorrow.” Now, that doesn’t follow. I mean, from the law of identity, nothing follows about limitations on change. The weather is identical to itself but it’s changing all the time. The use that’s made by people in the Randian tradition of this principle of logic that everything is identical to itself to place limits on what the future behavior of things can be, or on the future nature of current things, is completely unjustified so far as I can see; it’s illegitimate.

JS: So even if they have good politics, you don’t care much for the Objectivist approach?

RN: I’m going to alienate a number of your book orderers, if I didn’t already with what I said about Rand, but there was something startling about the attraction to non-​initiation of force principles that the Randians had, at the same time that they were diligently acting as thought police. Bold entrepreneurs? Yes. But bold exploration of ideas? No.

JS: Why do you think it is that people of generally illiberal temperament would pick up classical liberal ideas? The combination seems mysterious.

RN: It is mysterious. Perhaps it has to do with the two sides of libertarian ideas. There is the boldness and excitement of libertarian ideas, the new possibilities for thinking, and for life in society that they open up, and there also are the sharp, and sharply reasoned, weapons they provide for attacking and even crushing other ideas. So perhaps it is not surprising that libertarianism has attracted two distinct types of temperaments, each one resonating to one of libertarianism’s two different aspects.

JS: Would you say that someone like, say, [philosopher of language] Saul Kripke, and Ayn Rand, are making a similar metaphysical mistake?

RN: Well, neither of them would want to be classed with the other, but they are each attributing to us capacities of intellectual apprehension beyond what we have any good reason to think evolution has given to us.

JS: Although it also seems that the vast majority of our cognitive capacities, even the ones we don’t doubt terribly much, stretch beyond what we might expect would be required merely to survive and reproduce.

RN: Well, it may be that we don’t have such a good understanding of what’s required to survive and reproduce, and of what gives one differential advantages in survival and reproduction. There might be very subtle things that are going on. Various studies in the behavioral ecology of animals are constantly turning up surprising functions for things that people used to think didn’t have functions at all, and surprising ways that behavior is optimal or close to optimal when it really didn’t seem as though it was performing an important function. So there’s a lot left to learn.

JS: I want to touch briefly on your ideas about consciousness. You say that consciousness is, or may be, the process of streams of information merging in the brain.

RN: Yes.

JS: Why does that have to be conscious? Why would there be something it’s like, from the inside, for information to merge that way?

RN: Because that’s the process that’s putting us in closer touch with the way things are in the world so we can more accurately conform our behavior to the contours of things in the world and, also, that’s the process through which we can focus more closely or more distantly on aspects of the world.

JS: You’re referring there to your “Zoom-​Lens” theory of how we bring different parts of the world to “center stage.”

RN: Right.

JS: Some say, though, that in terms of explaining a system’s physical behavior, and even the “fit” of that behavior to the world, you would never need to invoke some subjective character behind the behavior. Is that sort of objection just misguided?

RN: No, I think it’s not a misguided objection, but the question is whether it can be answered. One possibility is that you don’t have to refer to some “subjective character”, but that you have to refer to phenomena and causal processes that are “emergent” in the sense of “not reducible to general laws that apply to non-​conscious processes as well.” So you might say, I don’t have to refer to the conscious aspect of things to explain this behavior. I have a causal law that explains it. But this causal law is one that’s applying to certain sorts of complex systems and is not derivable from the concatenation of causal laws that apply to simpler ones. So we don’t have, in that sense, a unified science, but we have causality everyplace. And in a certain sense, you can say, “If it weren’t conscious, this wouldn’t be happening.” That is, the consciousness is marking off the presence of special causal properties that aren’t reducible to more general ones.

JS: If that’s the case, should we expect physicists, when they get fine-​grained enough CAT-​scan like devices, to be mystified by the behavior of brain states?

RN: That’s a good question. If that’s the case, then yes, if they get fine grained enough.

JS: So this is, in principle at least, a testable theory. We may know at some point whether consciousness has this special character. And even if it turns out that it’s not the case, that’s an equally interesting result.

RN: That’s right

JS: You observe in the very first chapter, where you talk about relativism and absolutism, that people’s belief that truth is either relative or absolute tends to reflect the way they want things to be. You, on the other hand, seemed to conclude that truth is perhaps not quite so absolute as you would have liked it to be. What would you have liked to have shown, and what do you think you did show?

RN: Well, for one, truth is not socially relative among human beings. It doesn’t vary with race or sex or sexual preference, or anything sexy like that. But when I started to think about very different environments in the universe with very different kinds of beings that might live in them, and realized that they might have, to use the locution of the book, different truth properties, different features of belief upon which their success in action depended, that surprised me. Now, I didn’t want the standard argument that said relativism is incoherent to go through. (The argument runs: “But what about the relativist position itself? Is its truth supposed to be absolute or relative? If absolute, what’s so special about it? Why can’t there be other absolute truths? But if its truth is only relative, then why should I believe it?”) I used to use that argument, as a lot of us do in philosophy. But then it struck me that it would be more interesting if relativism were coherent but false. Then non-​relativism would be denying something coherent, and would have Popperian empirical content. So I set about to try to construct a coherent relativism, to show that it was false. Then when I got to these different kinds of being elsewhere in the universe, and seeing whether truth could be relative between us and them, not to mention beings in other possible worlds, it seemed like, yes, maybe it could be. I didn’t have much invested there, in whether it was or not; it was just of some abstract philosophical interest that it could be.

JS: I don’t see many post-​structuralists taking much comfort in the thought that Martians in some other modal context might not have the same truth property that we do.

RN: That’s right. Another form of relativism, one that I do take seriously and find very interesting, is not a social relativism. I put it close to the front of the chapter, even though it contained technical material about quantum mechanics. I think that quantum mechanics and relativity theory might show us a surprising relativism about truth, that it is relative to time and place, and they do this on the basis of empirical results. That is an interesting and surprising possible connection between philosophy and science.

JS: You seemed to be saying in this part of the book that not only is the future not written, the past is a little blurry too.

RN: That’s right.

JS: This reminds me a bit of a line delivered by O’Brien in Nineteen Eighty-​Four, to the effect that the past has no real existence if you don’t have evidence that it happened as it did. Whoever controls the present controls the past.

RN: Well, I’m not putting forward a verificationist view. You don’t actually have to have the evidence. But the past events have to have made some current difference, whether you (are in a position to) know of that difference or not.

JS: Now a lot of people would, I imagine, find that strongly counterintuitive. Even if there were not a trace of an event that happened a million years ago, they’d say there is a fact of the matter whether it happened or not. You say there may not be a fact of the matter.

RN: Yes, there may not be a fact of the matter now. I want to tie something’s being true now to its being determinate now.

JS: Are those two necessarily overlapping?

RN: Not necessarily, but I am arguing that the fruitful and interesting notion is determinateness. Truth that floats free of that is a non-​science fiction.

JS: As you say, though, even if truth is relative in this sense, that isn’t what postmodernists and the like have in mind when they say that “truth is relative.”

RN: There’s a section in the book on why people are interested in relativism, why the relativists want it to be true and others don’t. That’s psychological speculation though, which looks behind the philosophical disagreement to the different kinds of motivation that people have.

JS: That’s the idea that the empirical evidence is so overwhelmingly in favor of capitalism, that relativism is the last gasp of the academic left.

RN: Right, the attraction to [Thomas] Kuhn, who seemed to enable people to say, “you have your paradigm, I have mine.”

JS: Are these sorts of academics fading away? It’s kind of hard to tell; we still have a few tenacious Marxists at NYU.

RN: They’re moving on. Literary studies is full of what’s become of Marxism in various guises. In The Examined Life (1989), I wrote (referring to the academic left in universities), “Marxism repeats itself, the first time as tragedy, the second time as farce.”

JS: Are they less dangerous in the English department than they were in the politics and philosophy departments?

RN: Well, I guess so in that their students don’t go on to as many positions of power and so forth. How do things look at NYU, where you are? How do people respond? Do you speak up? Are people aware of your opinions on things relevant to libertarian issues?

JS: Well, personally, I try not to be that one obnoxious guy in every class who knows very little but loves to hear himself talk. But I find I can’t help but speak up occasionally when there are, especially left leaning professors, who have gotten the idea that they can teach their own very idiosyncratic view and know that they’re not going to find any opposition. Like a Kitty Genovese situation where everyone looks around, and nobody else is doing anything, so it must be OK. Then I feel I at least have to make it obvious that these aren’t views that every reasonable and decent person just agrees with and nods along to. But that’s politics courses, really. The philosophy department here is very good in that respect. I was impressed with how reasonable and straightforward Frances Kamm, for example, was about dealing with objections I raised when I took her bioethics class.

RN: Yes, she’s an excellent philosopher who is very serious about the quality of arguments. It’s the difference between people who want to meet arguments, even when they disagree with their conclusions, and those who want to dismiss arguments by scorn or contempt, so that the class doesn’t think about those arguments, and isn’t tempted to accept them. Those professors probably don’t know how to answer the arguments anyway.

JS: In The Examined Life, you reported that you had come to see the libertarian position that you’d advanced in Anarchy, State and Utopia as “seriously inadequate.” But there are several places in Invariances where you seem to suggest that you consider the view advanced there, broadly speaking, at least, a libertarian one. Would you now, again, self-​apply the L-​word?

RN: Yes. But I never stopped self-​applying. What I was really saying in The Examined Life was that I was no longer as hardcore a libertarian as I had been before. But the rumors of my deviation (or apostasy!) from libertarianism were much exaggerated. I think this book makes clear the extent to which I still am within the general framework of libertarianism, especially the ethics chapter and its section on the “Core Principle of Ethics.” One thing that I think reinforced the view that I had rejected libertarianism was a story about an apartment of [Love Story author] Erich Segal’s that I had been renting. Do you know about that?

JS: I did hear about that. The story that had gone around was that you had taken action against a landlord to secure a certain fixed rent?

RN: That’s right. In the rent he was charging me, Erich Segal was violating a Cambridge rent control statute. I knew at the time that when I let my intense irritation with representatives of Erich Segal lead me to invoke against him rent control laws that I opposed and disapproved of, that I would later come to regret it, but sometimes you have to do what you have to do.

JS: Do the other professors pick on you because you’re the “libertarian kid,” so to speak? Has that been an albatross around your neck?

RN: No, not in the philosophy department certainly. (And I have been treated very well by the university administration.) Behind my back at the university, who knows what goes on, but not to my face. There was a time some years ago in the aftermath of Anarchy, State and Utopia when it was probably the case that my social life was somewhat curtailed. There may have been many parties I wasn’t getting invited to because people despised the views in my book. But if so, I didn’t notice it very much at the time.

JS: The students were not overly hostile either?

RN: Ah, that’s different. The Harvard graduate students of the late 60s and early 70s were the center of SDS activity on campus. I had been here for two years as an assistant professor, and left and went to Rockefeller University for two years, and came back in 1969 when I was 30 years old as a full professor. In the previous semester, students had taken over the university’s main administration building; their occupation was ended by police action. Feelings ran high. I announced a course, and it was printed in the catalog, titled “Capitalism,” in the philosophy department. The course description was “a moral examination of capitalism.”

JS: I see. I imagine the students expected something very different from what they got.

RN: That’s right. Somehow a rumor had spread, or maybe they saw what books were there in the textbook section of the bookstore, where in addition to something by Marx and some socialist book were Hayek and Mises and Friedman. So one graduate student came up to me at the beginning of the term and said, “We don’t know if you’re going to be able to give this course.” This was a graduate student in philosophy. And I said, “What do you mean?” He said: “Well, you’re going to be saying things…” and he mumbled something, “there may be interruptions or demonstrations in class.” And I said -- I was then, you have to remember, 30 years old -- I said, “If you disrupt my course, I’m going to kick the shit out of you.” He said, “You’re taking this very personally!”

[laughter]

I said, “It’s my course. If you want to pass out leaflets outside the classroom door, and tell people that they shouldn’t come in and take the course, that’s fine. I won’t allow you to do things inside the classroom.” He said, “Yes, well, we may pass out leaflets.” Time went by and nothing happened during the first week, the second week. So I saw him in the hallway and asked, “Where are the leaflets?” He said, “Well, you know, we’re very busy, we have a lot of things to do these days.” I said, “I called my mother living in Florida and told her that I was going to be leafleted, now come on!” But nothing ever happened.

JS: Have you thought about turning your attentions again to political philosophy, or have you more or less lost interest in that?

RN: I have thought about it, but it’s not next on my agenda. This coming year, after seven years of work on Invariances, an abstract book, I wanted to think about things that felt more concrete to me. Since I think about topics through teaching courses on them, this fall I’m giving a philosophy of history course. It will be structured by issues about explanation, causality, and so on, in the context of a case study on the Russian Revolution. I’m giving it jointly with a professor of history.

That’ll be interesting; I’ve been reading a lot of material about that. And in the spring, I’m giving a course jointly with a professor in the Slavic Languages department on Dostoyevsky and his philosophical ideas, and the difference that is made when philosophical ideas are presented in works of fiction rather than in discursive prose.

JS: Any chance of that seeing print?

RN: Well, it depends on what ideas I come up with.

JS: How do you feel about this new book? Are you happy with it?

RN: Very. Of my six books, I think that the three that are intellectually most exciting Anarchy, State and Utopia , Philosophical Explanations, and Invariances.

JS: And the one that is the very most exciting?

RN: [laughs] It’s a three-​way tie.