ROBERT NOZICK. By A. R. Lacey. Princeton Univ. Press. 248 pp. $17.95

INVARIANCES: The Structure of the Objective World. By Robert Nozick. Harvard Univ. Press. 416 pp. $35

Robert Nozick, the Harvard University philosopher who died in January at 63, earned his considerable public reputation with his first book, the libertarian manifesto Anarchy, State, and Utopia (1974). He had mixed feelings about this reputation, because he never really considered himself a political philosopher. After ASU, he devoted almost all his attention to the big problems of philosophy: value, knowledge, rationality. Ambitious topics, certainly, yet with Nozick there has always been a sense of ambition not quite fulfilled, of expectations not quite met.

There are two reasons for this. The first is methodological. Especially in his later work, Nozick rejected the notion of "proof" as the aim of philosophy. He sought to say things that were "new and interesting," even if not, strictly speaking, true—concocting inventive explanations for how it could be that there is something rather than nothing, for instance, or for why we might have free will. Second, his writing is not always accessible. ASU is rightly praised for the clarity and liveliness of its prose, but his next book, Philosophical Explanations (1981), is long, dense, and frequently unrewarding. As Nozick himself confessed, in some parts he was merely "thrashing about."

As a result, Nozick has long been in need of a critical expositor, someone to present his philosophy in a straightforward yet rigorous fashion. This is Lacey’s goal, and the results are mixed. The book, clear if rather stiff, covers every major aspect of Nozick’s thought, including his original contributions to epistemology, rationality, and metaphysics. Yet by the end, even the careful and sympathetic reader may be left wondering just what Nozick was about.

Lacey begins each chapter with a short overview of the general nature of the philosophical problem to be considered, followed by a too-brief statement of Nozick’s position and then a look at the objections raised by critics. Lacey presents the critical response in all its breadth instead of focusing on a sustained and consistent line of criticism, so the book often reads like an annotated bibliography. The treatment of ASU is especially disappointing: That book was in many ways a direct response to John Rawls’s A Theory of Justice (1971), but Lacey gives Rawls versus Nozick a mere two pages. In fairness, Nozick made a point of not responding to critics or revising his views in light of objections. He didn’t want to become "defensive" about his work, and he often joked that he didn’t want to spend his life rewriting ASU—a dig, perhaps, at his colleague Rawls, who made a career of revisiting A Theory of Justice.

Regardless, the philosophy that emerges from Lacey’s study has an unfinished feel to it. That feeling persists in Nozick’s last book, Invariances. He again tackles some big questions—necessity, objectivity, consciousness—and the book demands a lot from the reader. Nozick was a stupendously learned man, but that learning was not always lightly worn. In justifying once again his rejection of philosophical proof, he compares his method to that of physicists who use messy mathematics to make quick progress in a new area. He casually invites the reader to "recall the state of the calculus before [Karl] Weierstrass, and the path to renormalization methods in quantum field theory"—and this is only the introduction. Still, there is some great philosophy here. The discussion of evolutionary cosmology and how it might give us objective worlds is state-of-the-art metaphysics, both new and exciting.

Nozick is an important philosopher who led an interesting life. With his passing, what we need, and what he deserves, is an intellectual biography with the scale and scope of Ray Monk’s book on Ludwig Wittgenstein.

—Andrew Potter