Paolo Crivelli

Some philosophers argue that false speech and false belief are impossible. In the Sophist, Plato addresses this 'falsehood paradox', which purports to prove that one can neither say nor believe falsehoods. In this book Paolo Crivelli closely examines the whole dialogue and shows how Plato's brilliant solution to the paradox is radically different from those put forward by modern philosophers. He surveys and critically discusses the vast range of literature which has developed around the Sophist over the past fifty years, and provides original solutions to several problems that are so far unsolved. His book will be important for all who are interested in the Sophist and in ancient ontology and philosophy of language more generally.

Aristotle created logic and developed it to a level of great sophistication. There was nothing there before; and it took more than two millennia for something better to come around. The astonishment experienced by readers of the Prior Analytics, the most important of Aristotle's works that present the discipline, is comparable to that of an explorer discovering a cathedral in a desert. This article explains and evaluates some of Aristotle's views about propositions and syllogisms. The most important omission is the difficult subject of syllogisms involving modalities. Aristotle distinguishes two relations of opposition that can obtain between propositions with the same subject- and predicate-expressions: contrariety and contradiction. In every canonical syllogism, one term is common to the two premises: it is called “middle term,” or simply “middle.” The remaining two terms of the premises are the only ones occurring in the conclusion: they are called “extreme terms,” or simply “extremes.”

Definitions were very important for the Stoics, even though they hesitated as to where the theory of definition should be located within their system of philosophical disciplines: some (probably Chrysippus) placed it in the methodological subsection of the logical part, others in ethics, yet others in the subsection of dialectic relating to voice. The first of these locations focuses on the epistemological side of the theory of definitions. In particular, it is connected with two roles played by definitions: sharpening our conceptions in such a way that they are more successfully applied to or withheld from entities, and endowing our conceptions with a systematic structure that makes them suitable for instruction. The Stoics do not think that definitions reveal the essence of what is defined. As for the link with the Stoic theory of language and meaning, definitions are not linguistic expressions, but sayables of a special kind (distinct from statables).