Edited and written by David Gordon, senior fellow of the Mises Institute and author of four books and thousands of essays.

Winter 2001; Volume 7, Number 4

A Substitute for Knowing

Invariances: The Structure of the Objective World by Robert Nozick (Harvard University Press, 2001, x + 416 pgs.)

Readers of this journal will probably be most interested in Nozick’s views on ethics, especially as they relate to libertarianism, and it is on these that I propose to concentrate. In doing so, I run the risk of distortion. Invariances is full of new ideas, and no review that stresses a small part of the book can do it justice. 

Nozick’s remarks on libertarianism, though brief, are full of interest. He distinguishes several layers of ethics: "The first layer is the ethics of respect, which corresponds to an (extended) ethics mandating cooperation to mutual benefit. Here there are rules and principles mandating respecting another (adult) person’s life and autonomy, forbidding murder and enslavement, restricting interference with a person’s domain of choice, and issuing in a set of (what have been termed negative) rights" (p. 280, emphasis removed). Other layers, such as the ethics of caring, go beyond the duty of noninterference with others and call for positive aid to them.

Given these various levels, the question at once arises: which of them, if any, may be enforced by coercion? In his response, Nozick weighs in as a libertarian: "The ethics of respect . . . is the part, the one part (I think) that is (that should be) mandatory across all societies. . . . [S]ome particular society may attempt to make one or another of these further levels mandatory within it . . . I also believe . . . that no society should take this further step. All that any society should (coercively) demand is adherence to the ethics of respect" (pp. 281–82).

Can one defend libertarianism adequately on this basis? At first sight, one might think so: has Nozick not stated succinctly and accurately the essence of a free-market order? But his profession of belief raises a problem. What is the status of his contention that coercion should not pass beyond the ethics of respect? Can it itself be coercively enforced, or does it merely reflect a "personal ideal" that Nozick holds? Where does this principle fit within the doctrine of moral levels?

Unless Nozick holds that the principle limiting coercion to the morality of respect itself forms part of the morality of respect, he has failed to reach an adequate libertarian standpoint. To tell us that he himself prefers that society limit enforcement in this way has no more than biographical interest: the question is whether morality demands it.

There is, I think, a more fundamental problem with Nozick’s view of morality. He questions whether ethical truths exist at all. "How can ethical statements be true, if truth consists in correspondence to the facts? Are there special kinds of facts, ethical ones, and if so, by what route do we discover them? . . . The history of philosophy is abundant with unsuccessful attempts to establish a firm basis for ethical truths. Inductively, we infer that the task is unpromising" (p. 236).

But do not our considered moral judgments put us in touch with real values "out there" in the world? Nozick finds no basis in evolutionary theory to account for this claimed grasp of values. He then endeavors, with great ingenuity, to piece together an ersatz objectivity that makes no dubious claims about real values.

But why is Nozick’s project necessary? Suppose he is right that we cannot explain by use of Darwinian evolution how we can grasp ethical truth. Why should we take this as a decisive reason to abandon the claim that we know such truths? Perhaps we have instead grounds to doubt that Darwinian processes account for all our knowledge.

We might press the point further. It is hard to explain through evolution how we know necessary truths. Does this give us reason to abandon necessary truth? If not, why should we toss moral truths overboard on Darwinian grounds?

Nozick of course fully anticipates this response. Indeed, it is virtually impossible to think of a point that this most brilliant and imaginative of contemporary philosophers has not already considered. But his answer I find astonishing. He does propose to abandon necessity, in large part because he cannot account by evolution for how we might attain such knowledge. Why he accords evolutionary considerations such enormous weight escapes me.

But my skepticism is not an argument, and Nozick’s intricately elaborated alternative to ethical truth merits attention. Once again, Darwinian evolution exerts decisive weight. Nozick endeavors to determine the evolutionary function of ethics. Why has natural selection endowed us with the capacity to make moral judgments? He plausibly suggests that cooperative behavior in some circumstances increases that be-all and end-all of those enamored of evolutionary theory, "inclusive fitness."

Suppose Nozick is right. Why does this matter for ethics? As always, our author has considered the objection: "Derek Parfit . . . asks the pertinent question of what difference is made by something’s being the function of ethics. Many things have bad functions (war, slavery, etc.). And even when the function is a good one, as evaluated by the standards instilled to go with cooperation, is normative force added by saying that this good effect of ethical principles (namely, enhancing mutual cooperation) also is the function of ethics?" (p. 390, n. 15).

Nozick’s response brings out a key feature of the book. Ethical rules not only have a function but also exhibit certain properties that enable them to carry out this function effectively. One of these has to our author decisive importance. "Objective ethical truths . . . are held to involve a certain symmetry or invariance. . . . The Golden Rule mandates doing unto others as you would have others do unto you" (p. 289). As Nozick sees matters, invariance under transformation is the mark of truth. Once we combine function with invariance, in a vastly more complicated way than I can here explain, we arrive at objective truth—or at least a close substitute for it.

Surely Nozick is right that cooperative behavior of various sorts might have benefited our ancestors. On evolutionary grounds, though, would not a tightly knit group able to prey on others also have enjoyed a selective advantage? So, at any rate, Sir Arthur Keith long ago maintained in A New Theory of Human Evolution. Why do not rules that mandate aggression against strangers also qualify as part of an objective ethics? Nozick might counter with the claim that such rules do not admit of generalization in the way that he holds is required for objectivity. But this remains to be shown. Generalization need not bring us to "love to all people, perhaps all living creatures," much less to "being a vessel and vehicle of Light," the two highest levels of Nozick’s ethics (p. 280); it can equally well eventuate in a far more Nietzschean outcome. It all depends where one starts.

Faced with Nozick’s convoluted analysis, which he himself worries has too many epicycles, one wants to say: can’t he just see that values are really present in the world? Why need one abandon what is self-evident in favor of a speculative and endlessly imbricated substitute for genuinely objective values?

Here we reach bedrock. Fundamental to Invariances is Nozick’s distrust of claims of direct knowledge of the nonempirical. We do not "just know" that people have rights, anymore than we directly see that both sides of a contradiction cannot at the same time be true. Once again, evolution forbids it. "Such debates [about necessary truth] would be avoided if we possessed a faculty of reason that could directly assess the possibility of general statements and of their denials. . . . However, we do not appear to have such a faculty, and it is implausible that evolutionary processes would instill that within us" (p. 122). 

But does this not create a problem for Nozick’s libertarianism? He famously began Anarchy, State, and Utopia by telling us, "Individuals have rights." Are not such absolute claims ruled by Nozick’s newly installed divinity, Evolution? He can at most say that an evolutionary fable makes somewhat plausible that one can hold, as a personal ideal, that people cannot be coerced beyond what the level of respect mandates. This hardly seems worth writing home about.

Nozick’s rejoinder is obvious. No doubt it would be convenient for libertarians if we could claim our doctrine to be true a priori; but fairness to the facts requires that we abandon this claim. And to support his denial that we directly grasp necessary truth, he deploys an intriguing argument. To claim something is necessarily true is to say that it is true in all possible worlds: it cannot be otherwise. Is this not an extraordinary claim to make? To claim, by contrast, that something is possible is a much more modest assertion. "It is easier to think of possibilities than of necessities, easier to know that something is possible than that it is necessary" (p. 121). Do not exponents of necessary knowledge seek mistakenly to limit the imagination? Who are we to say that something must be so?

Many things, no doubt, are easy to imagine; but our ability to think of something hardly shows that it is really possible. If something is possible, then nothing in any possible world renders it impossible. Is this not as radical a claim as the one Nozick would deny to us? Oddly, Nozick elsewhere makes an analogous claim: "[A] theory can appear consistent and transparent . . . yet still harbor contradictions. . . . Not everything that looks consistent really is possible" (p. 162). But he does not note the bearing of this on his earlier contention. Nozick’s argument leaves claims to necessary truth undamaged, unless he also wishes to throw into question our knowledge of possibility.

Further, why do those who claim direct access to real values have to say that propositions about value are necessary? Why is it not enough to assert that the value propositions are true? Nozick goes to great lengths to imagine "an admittedly extremely gruesome" case in which it is not wrong to torture babies to death for fun (p. 349, n. 35). Even if one seriously entertains his case, does this throw into doubt our knowledge that, in the actual world, such torture is wrong?

Nozick has studied carefully a wide range of difficult subjects, quantum mechanics and string theory not least among them; and I cannot pretend to grasp more than a few regions, on earth or near it, of his vast philosophical cosmos. I shall close with a few points of detail. One of his arguments that the law of noncontradiction may fail to hold depends upon a questionable appeal to a principle of sufficient reason (p. 303, n.1). He seeks to disarm C.I. Lewis’s claim "that each relative statement corresponds to an absolute one, viz., the one that makes the relativity explicit" by adducing Einstein’s theory of relativity.

But the claim that Einstein’s invariant statement is "not simply the explicit statement (à la C.I. Lewis) of this relativity" leaves Lewis’s assertion intact (p. 319, n. 76). He takes "nothing can be red and green all over at the same time" to be about whether these particular two colors can be combined. The fact that we cannot see reddish green he takes to depend on contingent scientific facts; hence the much-debated statement is not necessary. But the proposition is not about mixed colors at all (pp. 136–38). His statement about wave-packet collapse, "that failure of derivability comes precisely at the point where physical systems that are identical with conscious beings interact with physical systems in a superposition" (p. 230), begs the question against dualism about the mind.

Though I find myself in strong disagreement with many of the views in Invariances, I closed the book with admiration. The old master has not lost his power to fascinate. What an extraordinary mind, and what an unusual way of looking at the world!


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