third essay, to the accuracy of the “computer” model for the human mind. The fourth essay advances an argument about intentionality, the structure of human action in the world, which seeks to clarify and resolve some of the difficulties already presented. Having given these arguments, Searle uses the last two essays to consider consequences in particular areas of concern: the status of the social sciences in the hierarchy of scientific endeavor (in the fifth essay) and the freedom of human will (in the sixth). Closing with a brief reading list for further study and a name-subject index, the volume thus surveys some of the most provocative and contentious areas in the realm of epistemology, ethics, and philosophy of mind.

Searle’s method in dealing with these various problems is grounded in his philosophy, the study of the formal relationships between the ultimate structures of language and reality. In general, he approaches the claims made for each position as definitions reducible by strictly logical, syntactic analysis to lucid statements of relationship between ultimately existent things; definitions which fail this test of lucidity and relationship must therefore be regarded as errors distorting accurate knowledge of reality. Unlike Russell, the originator of the analytical school, Searle does not finally identify an irreducible pluralism—as between mind and matter, for example—in the constitution of the universe; indeed, the earlier chapters of this book support a fundamentally materialist, monistic constitution of reality, whereby appearances of pluralism are explained by the differences in the manifestations of physical reality at the subatomic (Searle’s “micro”) and sensible (“macro”) levels.

An outline of the austere analytical method, however, does not do justice to its manifestation in this book, which, although occasionally difficult, is neither arcane nor academically pretentious. In part because Searle sometimes bases his arguments upon “commonsense” propositions (that is, upon the use of language by naïve speakers who accept without question the conventions of their language system), his development of analytical constructs generally proceeds by analogy from the immediate and familiar to the abstract and difficult. Furthermore, the analogies themselves provide Searle with the opportunity to display both the acuity and the whimsy that are characteristic signs of his wit. Overall, then, despite the rigorous approach and the intellectual difficulties, the text itself is highly readable and comprehensible if one is willing to accept the conditions of the various arguments’ development.

The first essay, “The Mind-Body Problem,” addresses the central topic from which the topics of the later essays may be drawn as corollaries. Searle attempts to answer the long-canvassed problem of mental-physical dualism by pointing out that the mind and the body interact, but not as separate or discrete entities, since the mind is a “macro” manifestation of physical characteristics of the brain. This position allows him to address several related problems—the possibility of consciousness and of intentionality, the accommodation of mental subjectivity in objective physical reality, and the mental causation of physical events—by asserting that, since mental experiences have their basis in physical reality (that is, in the microstructure of the brain), there is no inconsistency in holding both the physicalist and the mentalist views simultaneously: “As far as we know anything about how the world works, they are not only consistent, they are both true.”

As its title suggests, the second essay, “Can Computers Think?” considers the matter of artificial intelligence and the claims of computer technology to have created “thinking machines,” claims that would necessarily deny the biological nature of human thought. Through a series of “thought experiments,” Searle argues that, since computers are machines, physical systems that perform certain kinds of binary manipulations with data, they may be said to possess a syntax (that is, the rules for manipulating the data) but not a semantics (that is, the system by which meaning may be derived from the data). Thus, computers may be able to simulate certain processes without being able to duplicate their meaning. In other words, computers are defined by their formal structure, whereas minds are defined by their mental contents (or semantic systems). As a result, Searle argues, a computer program may provide the syntax (or formal structure) that mimics a mind, but no program could provide the semantic powers necessary to create a mind—a position that reinforces the first essay’s claim of the biological nature of mental states.

In the third essay, “Cognitive Science,” Searle investigates the validity of attempts to place theories about human behavior on a scientific footing of the same kind as used in physics or the other hard sciences. In attacking cognitivism, Searle admits its attraction: Our present explanatory models for human behavior (often derived from computer technology) incline us mistakenly to assume an identity between the “rules” that machines follow and the “rules” that humans follow, especially when no other explanation of the relationship between mind and brain is available. Using material developed in the previous lectures, Searle argues that cognitivism mistakes the character of the rules that humans follow, since those rules do not strictly depend upon the formal structure of behavior but rather upon the meaning that shapes that formal structure. From the outside, Searle argues, machines and humans appear to follow the same kinds of rules; the differences—overlooked by cognitivism—lie in the mental content with which humans invest such rules and which machines can simulate but not duplicate. In conclusion, Searle argues that there is no need to posit an area of inquiry such as that claimed by cognitivism, since there is no intermediate level of phenomena between the mental states and the physical structures that produced them.

As a group, the first three essays lead directly to the inquiry set out in the fourth essay, “The Structure of Action,” which addresses the place of intentionality in human behavior, a topic that Searle examines in much greater detail in Intentionality: An Essay in the Philosophy of Mind (1983). Searle identifies three characteristics of human behavior: first, that intentional states have both a form and a content of a certain type; second, that these states include notions of the conditions of their satisfaction; and third, that these states sometimes cause things to happen. In less abstract terms, human intention includes both a mental and a physical component (as, for example, the intention to walk home), the conditions necessary to realize the intention (walking toward, then arriving at home), and sometimes the beginning of that realization (by engaging in the appropriate physical actions of directed walking, and so on). Second, since human beings in intentional states can identify both the intention and the physical action that they think will realize the intention, any explanation of behavior must have the same content as the intention that causes that behavior. Finally (and most significantly in terms of Searle’s other work), intentions are shaped by their relationship to a “network” of other intentions that qualify and characterize the conditions of satisfaction represented in the intention itself, and the whole network of satisfactions is itself shaped by human characteristics and qualities that are not themselves mental phenomena.

The fifth essay, “Prospects for the Social Sciences,” takes up some of the material already canvassed in the third essay in order to examine the claims of the social sciences to be scientific in the strictest sense. Searle points out that the social and natural sciences are radically unlike in character and quality. This unlikeness is not merely the consequence of the difference between social and (nonhuman) physical phenomena nor that of the unsystematic form that social phenomena present. According to Searle, the fundamental difference between the natural and social sciences, and the reason that the social sciences will never be able to attain to the same level of systematic application, lies in the different sources of action that apply to the different areas of inquiry: The physical sciences address actions that spring from wholly physical sources, whereas the social sciences address actions springing from the mind. Thus, as Searle argues in the earlier essays, since the kinds of actions addressed are constitutively different, the criteria of judgment must also be different, so that the social sciences err insofar as they attempt to pursue the goals appropriate to the natural sciences.

Searle undertakes an examination of perhaps the most basic of the questions that he addresses in the last essay, “The Freedom of the Will.” He begins with a review of the three positions that are most commonly offered to the problem of human will: determinism, the idea that all events and actions are determined by physical constraint; free will, that all mental events and intentions are open to the free choice of the human being; and compatibilism, the position that accepts a human free will limited but not constrained by physical necessity—“it is that corner of determined human behaviour where certain kinds of force and compulsion are absent.” After reviewing the positions and the various arguments and evidence in support of each, Searle considers whether any of the three is consistent with the view of human mental and physical reality as outlined in the earlier essays, concluding that the model of the mind-brain relationship that he provided in the first essay (and supported by scientific inquiry since the beginning of the modern period) offers no place for truly free will. Rather, Searle argues, human beings live their lives upon the founding assumption that their actions are free and that they remain free in intention despite physical constraints that prohibit the satisfaction of some of those intentions.

As a whole, Minds, Brains and Science, although witty and refreshing to read, presents a bleak picture of the human relationship to the physical universe. On the one hand, the early parts of the book appear to reclaim some particularly human characteristics of thought and intention from the grasp of those who champion artificial intelligence; on the other, Searle’s basic model of the mind-brain relationship and its implication in the structure of a universe determined at the microlevel make those human characteristics perhaps less valuable. His general argument, that there is no fundamental inconsistency between the commonsense notion of mental life and the nature of the physical universe as described by the sciences, may resolve a long-standing philosophical question, but it does so by abandoning humankind’s claims to any conspicuous singularity.