The following review was written before news of Robert Nozick’s death in January. He was Arthur Kingsley Porter Professor of Philosophy at Harvard, and was named a University Professor there in 1998, Harvard’s most distinguished professorial position. Anarchy, State, and Utopia, published in 1974, when Nozick was only thirty-five, was his most publicly visible book, but he wrote several others—most notably, I think, Philosophical Explanations (1981). A recent collection, Robert Nozick, edited by David Schmidtz (Cambridge University Press, 2002), contains essays by ten distinguished philosophers on aspects of Nozick’s philosophy. I never met him, but always admired his prodigious energy and undeniable brilliance. My review is, I hope, written in a spirit of open and honest criticism of which I think he would have approved. I had fully expected a strong reply from him in the correspondence columns of this journal, but that is not to be.
Robert Nozick’s intellectual energy is a thing of wonder. In Invariances he ranges copiously over relativity theory and quantum theory, cosmology, modal logic, topology, evolutionary biology, neuroscience, cognitive psychology, decision theory, economics, and even Soviet history—not to mention his strictly philosophical forays into the nature of truth, objectivity, necessity, consciousness, and ethics. There are one hundred pages of tightly packed footnotes to three hundred pages of text. The effect (or the method) is to overwhelm the reader with a heavy arsenal of erudition. Duly intimidated, thoroughly outclassed, reduced to silence, the reader may find himself brooding on his shortcomings.
Nozick’s avowed aim in this book is to bring science to bear on philosophy. He writes:
In investigating the functions of truth (true belief), objectivity, ethics, and consciousness, we will have occasion to keep our eyes peeled for relevant scientific theories and scientific data. Philosophy is not (wholly) an a priori discipline, so it must mesh with current knowledge and also pursue promising and puzzling leads stemming from that knowledge. We shall also seek to identify and separate the empirical substrate or aspect of philosophical questions and, to the extent that this is possible, to transform philosophical questions into factual, empirical ones.
In keeping with this policy, Nozick recommends an exploratory style of philosophical research:
My own philosophical bent is to open possibilities for consideration. Not to close them. This book suggests new philosophical views and theses, and the reasons it produces to support these are meant to launch them for exploration, not to demonstrate conclusively that they are correct.
Not surprisingly, Nozick is an ardent fallibilist. There is, in his view, virtually nothing that we could not be wrong about—even logic and the existence of our own minds:
Everything is open to transformation. Nothing stays fixed. Even something as fundamental as the principle of noncontradiction can be open to questioning and to revision.
Cartesian certainty is not to be had. We have had our common-sense views shattered by science in the past, and there is no limit to how much further the shattering …