Nicholas Rescher

Leibniz said with a mixture of admiration and inspiration that the Duchess Sophie of Hannover always wanted to know the reason why behind the reason why. And that is just how rationality works: it wants to leave no loose ends to understanding, seeking to enable us to understand things through to the bitter end. In the twelve chapters that make up Satisfying Reason, Rescher develops and defends the following perspective: That rationality is a cardinal virtue in cognitive matters. That this is not something simple and cut-and-dried: in the pursuit of truth through the development of knowledge we face obstacles -- sometimes even insuperable ones. All that we can do is the best we can, realizing that even our very best may still be imperfect. Nevertheless, the venture is far from hopeless. While absolutes are unattainable in the cognitive venture, some solutions are situationally optimal, being comparatively the best that can be managed under the circumstances. That reason itself enables us to come to terms with this state of affairs, urging us to accept the best we can do as good enough. Satisfying Reason is an explanation of the presuppositions and methods of rational enquiry, an original exercise in metaknowledge, developing a systematic body of knowledge about the scope and limits of knowledge itself.

The increasingly lively controversy over scientific realism has become one of the principal themes of recent philosophy. 1 In watching this controversy unfold in the rather technical way currently in vogue, it has seemed to me that it would be useful to view these contemporary disputes against the background of such older epistemological issues as fallibilism, scepticism, relativism, and the traditional realism/idealism debate. This, then, is the object of the present book, which will recon sider the newer concerns about scientific realism in the context of these older philosophical themes. Historically, realism concerns itself with the real existence of things that do not "meet the eye" - with suprasensible entities that lie beyond the reach of human perception. In medieval times, discussions about realism focused upon universals. Recognizing that there are physical objects such as cats and triangular objects and red tomatoes, the medievels debated whether such "abstract objects" as cathood and triangularity and redness also exist by way of having a reality indepen dent of the concretely real things that exhibit them. Three fundamen tally different positions were defended: (1) Nominalism. Abstracta have no independent existence as such: they only "exist" in and through the objects that exhibit them. Only particulars (individual substances) exist. Abstract "objects" are existents in name only, mere thought fictions by whose means we address concrete particular things. (2) Realism. Abstracta have an independent existence as such.

Leibniz's optimalistic cosmology is one of the most controversial--and least appreciated--sectors of his philosophical system. How can contingency figure in a context where all truth is seen as analytic? Why should the best of possibilities be realized? And how can omni-necessitation be averted if an omni-benevolent deity must create the best possible world? Moreover, how can this supposedly best of possible worlds contain so much suffering and evil? Then too, how can there be a best, anyway, seeing that anything can be improved upon? And how can an imperfect creature of limited intelligence possibly hope to fathom such cosmic mysteries? All these questions convey objections to Leibnizian ideas that have been made repeatedly over many years. In actual fact, however, Leibniz anticipated them all. The aim of the present book is to lend plausibility to how he set about it.

ConclusionThe principal aim of the present paper has been the presentation of a semantical foundation for an important species of deontic logic (viz., the conditional variety). This semantical approach to the problem is essentially new and has the advantage of providing a complex of conceptual machinery by means of which this branch of applied logic can be placed upon a more rigorous and solid foundation. Above all, it makes available a logically rigorous criterion of acceptability for deontic principles by means of which questions in this sphere can be treated and resolved upon other than intuitive grounds.