The relationship between formal logic and general philosophy is discussed under headings such as A Re-examination of Our Tense-Logical Postulates, Modal Logic in the Style of Frege, and Intentional Logic and Indeterminism.

A Brief History of Time: From the Big Bang to Black Holes is a popular-science book on cosmology (the study of the origin and evolution of the universe) by British physicist Stephen Hawking. It was first published in 1988. Hawking wrote the book for readers who have no prior knowledge of the universe and people who are interested in learning.

This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

Two purported proofs of the incoherence of vague identity are considered. First gareth evans's attempt is criticized and reformulated to overcome certain formal difficulties. Despite the reformulation, However, Evans's proof is demonstrated invalid in accord with a supervaluational approach. Next nathan salmon's attempt is evaluated. Here the problem is salmon's implicit assumption of a version of leibniz's law which is stronger than that strictly guaranteed by the law as it is given in classical logic. The question is raised on what (...) grounds this stronger version is to be considered a logical law: without it the proof fails. (shrink)

The term fuzzy logic is used in this paper to describe an imprecise logical system, FL, in which the truth-values are fuzzy subsets of the unit interval with linguistic labels such as true, false, not true, very true, quite true, not very true and not very false, etc. The truth-value set, , of FL is assumed to be generated by a context-free grammar, with a semantic rule providing a means of computing the meaning of each linguistic truth-value in as a (...) fuzzy subset of [0, 1].Since is not closed under the operations of negation, conjunction, disjunction and implication, the result of an operation on truth-values in requires, in general, a linguistic approximation by a truth-value in . As a consequence, the truth tables and the rules of inference in fuzzy logic are (i) inexact and (ii) dependent on the meaning associated with the primary truth-value true as well as the modifiers very, quite, more or less, etc. (shrink)

The paper defends Gareth Evans's argument against vague identity. It appeals to a principle I name the principle of the diversity of the definitely dissimilar to defend the thesis that vague identity statements owe their indeterminacy to vagueness in language.