Moses Maimonides, scholar, physician, and philosopher, was the most influential Jewish thinker of the Middle Ages. In this magisterial new biography, the work of many years, Herbert Davidson provides an exhaustive guide to Maimonides' life and works. After considering Maimonides' upbringing and education, Davidson expounds all of his voluminous writings in exhaustive detail, with separate chapters on rabbinic, philosophical, and medical texts. This long-awaited volume is destined to become the standard work on this towering figure of Western intellectual history.

Cognitive science is, of course, not really a new discipline, but a recognition of a fundamental set of common concerns shared by the disciplines of psychology, computer science, linguistics, economics, epistemology, and the social sciences generally. All of these disciplines are concerned with information processing systems, and all of them are concerned with systems that are adaptive—that are what they are from being ground between the nether millstone of their physiology or hardware, as the case may be, and the upper (...) millstone of a complex environment in which they exist. Systems that are adaptive may equally well be described as “artificial,” for as environments change, they can be expected to change too, as though they were deliberately designed to fit those environments (as indeed they sometimes are).The task of empirical science is to discover and verify invariants in the phenomena under study. The artificiality of information processing systems creates a subtle problem in defining empirical invariants in such systems. For observed regularities are very likely invariant only within a limited range of variation in their environments, and any accurate statement of the laws of such systems must contain reference to their relativity to environmental features. It is a common experience in experimental psychology, for example, to discover that we are studying sociology—the effects of the past histories of our subjects—when we think we are studying physiology—the effects of properties of the human nervous system. Similarly, business cycle economists are only now becoming aware of the extent to which the parameters of the system they are studying are dependent on the experiences of a population with economic events over the previous generation.In artificial sciences, the descriptive and the normative are never far apart. Thus, in economics, the “principle of rationality” is sometimes asserted as a descriptive invariant, sometimes as advice to decision makers. Similarly, in psychology, the processes of adaptation (learning) have always been a central topic, at one time a topic that dominated the whole field of research. Linguistics, too, has suffered its confusions between descriptive and normative attitudes towards its subject. But we must avoid the error, in studying information processing systems, of thinking that the adaptive processes themselves must be invariant; and we must be prepared to face the complexities of regression in the possibility that they themselves may be subject to improvement and adaptation.It might have been necessary a decade ago to argue for the commonality of the information processes that are employed by such disparate systems as computers and human nervous systems. The evidence for that commonality is now overwhelming, and the remaining questions about the boundaries of cognitive science have more to do with whether there also exist nontrivial commonalities with information processing in genetic systems than with whether men and machines both think. (shrink)

It is shown how a causal ordering can be defined in a complete structure, and how it is equivalent to identifying the mechanisms of a system. Several techniques are shown that may be useful in actually accomplishing such identification. Finally, it is shown how this explication of causal ordering can be used to analyse causal counterfactual conditionals. First the counterfactual proposition at issue is articulated through the device of a belief-contravening supposition. Then the causal ordering is used to provide modal (...) categories for the factual propositions, and the logical contradiction in the system is resolved by ordering the factual propositions according to these causal categories. (shrink)

What can reason do for us and what can't it do? This is the question examined by Herbert A. Simon, who received the 1978 Nobel Prize in Economic Sciences "for his pioneering work on decision-making processes in economic organizations." The ability to apply reason to the choice of actions is supposed to be one of the defining characteristics of our species. In the first two chapters, the author explores the nature and limits of human reason, comparing and evaluating the (...) major theoretical frameworks that have been erected to explain reasoning processes. He also discusses the interaction of thinking and emotion in the choice of our actions. In the third and final chapter, the author applies the theory of bounded rationality to social institutions and human behavior, and points out the problems created by limited attention span human inability to deal with more than one difficult problem at a time. He concludes that we must recognize the limitations on our capabilities for rational choice and pursue goals that, in their tentativeness and flexibility, are compatible with those limits. (shrink)

The central concept of Carnap's probabilistic theory of induction is a triadic relation, c, the probability or degree of confirmation of the hypothesis, h, on evidence, e. The relation is a purely logical one. The value of c can be computed from a knowledge of h, of e, of the structure of the language, and of the inductive rule to be employed.

This paper uses a proof of Gödels theorem, implemented on a computer, to explore how a person or a computer can examine such a proof, understand it, and evaluate its validity. It is argued that, in order to recognize it (1) as Gödel's theorem, and (2) as a proof that there is an undecidable statement in the language of PM, a person must possess a suitable semantics. As our analysis reveals no differences between the processes required by people and machines (...) to understand Gödel's theorem and manipulate it symbolically, an effective way to characterize this semantics is to model the human cognitive system as a Turing Machine with sensory inputs. La logistique n'est plus stérile: elle engendre la contradicion! – Henri Poincaré ‘Les mathematiques et la logique’. (shrink)

Professor Aubert's ?three?stage rocket? (Inquiry, Vol. 26 [1983], No. 1) has reached periodic orbit. His comments on my earlier reply to his critique of my election predictions paper simply repeat arguments I have already refuted. In this note, I limit myself largely to pointing out Professor Aubert's misconceptions of what my position actually is. I find no reasons for revising the views stated in my original election predictions paper, nor any reasons for thinking that paper violated norms of scientific method (...) that prevail in the natural sciences. (shrink)