First published in 1999. Routledge is an imprint of Taylor & Francis, an informa company.

Much speculation on the sources of Duhem's historical interests fails to account for the major shifts in these interests: neither his belief in the continuous development of physics nor his Catholicism, when his Church was encouraging the study of generally Aristotelian scholastic thought, led to any interest in mediaeval science before 1904. Equally, his own claim that he was merely testing his views on the nature of physical theory is easily squared only with earlier work with no trace of mediaeval (...) science. Behind this discontinuity lies a major crisis. Though not a positivist, Duhem had based all his work on assumptions acceptable to positivists. One of these, the sterility of the Middle Ages, was refuted by his chance discovery of evidence of genuine mediaeval science in the autumn of 1903, but that left the doctrine of scholastic sterility intact. (shrink)

The aim of the essay is to devise a logic of conditionality which escapes the paradoxes which arise when the general conditional is identified with the universalization of the material conditional. The assumption I adopt is that the logic of one contingent form differs from that of another to the extent that the two forms have different confirmations and disconfirmations. The logic of conditionals is not, But that of their confirmations and disconfirmations is, At bottom truth-Functional; and the logical relations (...) between conditionals, And between conditionals and non-Conditionals, May be traced through the truth-Functional connections between their respective confirmations and disconfirmations. The approach necessitates the re-Definition of the notions of confirmation and entailment. A peculiarity of the system which emerges is that from it can be derived, Without existential assumptions, The twenty-Four valid forms of the syllogism, The relationships of the square of opposition and the other commonly accepted inferences of traditional logic. (shrink)

This paper first appeared in Modern Theology, Vol. 6, No. 3, July 1989. Copyright (c) Basil Blackwell Publisher Ltd., Oxford. Reprinted by permission.