I survey the difficulties of several probabilistic views of non-deductive argument and of inductive probability and propose to explicate non-deductive reasoning in terms of rational preference. Following a critical examination of Popper’s allegedly deductive theory of rational preference, I draw upon the work of Popper and Rescher to present my view which includes: (i) the conjecturing of a set of alternative answers to or theories or hypotheses about the questions prompting the inquiry and (ii) the “reduction” of this set via (...) plausibilistic principles of rational preference. (shrink)

I survey the difficulties of several probabilistic views of non-deductive argument and of inductive probability and propose to explicate non-deductive reasoning in terms of rational preference. Following a critical examination of Popper’s allegedly deductive theory of rational preference, I draw upon the work of Popper and Rescher to present my view which includes: (i) the conjecturing of a set of alternative answers to or theories or hypotheses about the questions prompting the inquiry and (ii) the “reduction” of this set via (...) plausibilistic principles of rational preference. (shrink)

This non-technical, easy-to-read introduction to symbolic logic discusses truth-functional and predicate logic in a simple and concise manner. Emphasizes indirect proof of an especially simple form, while avoiding entirely conditional proof. Proof construction is taught by using: finished proofs; partially completed proofs in which the students are to supply missing justifications for lines of proof; and partially completed proofs in which the students are to supply the missing lines of proof, given their justifications. The difficult topic of symbolization of sentences (...) is presented in a quasi-mechanical way which stresses the recognition of standard form expressions. (shrink)

In this paper I take Hempel’s raven paradox as the claim that statements of the form ‘∼Ru v Bu’, ‘u is not a raven or u is black,’ confirm the hypothesis h ‘(x)(Rx → Bx)’, ‘All ravens are black.’ Although Hempel discusses this using a criterion of confirmation expressed wholly in terms of deductive logic (see 1965, pp. 35-9), it has become more common to articulate criteria of confirmation using concepts of probability and, in particular, to employ the positive relevance (...) criterion of confirmation which says that, given background knowledge k, (i) e confirms h if and only if P(h/e.k)>P(h/k); (ii) e disconfirms h if and only if P(h/e.k)shrink)

In this valuable and interesting book, Quine gives us his current views on evidence, reference, meaning, intension, and truth. Viewing the problem of evidential support as that of specifying logical relations between the sentences of a theory and observation sentences, Quine presents a form of confirmational holism. Observation sentences are occasion sentences which are firmly and intersubjectively associated holophrastically with ranges of stimulations. Only testable sentences which directly imply observation sentences may be refuted by observation. All other testable sentences are (...) disconfirmed or retained only as components of larger blocks of sentences. Quine mentions, but does not develop, reasoning in support of hypotheses which uses background beliefs and "the technology of probability and statistics". (shrink)