Zev Bechler

Three events, which happened all within the same week some ten years ago, set me on the track which the book describes. The first was a reading of Emile Meyerson works in the course of a prolonged research on Einstein's relativity theory, which sent me back to Meyerson's Ident ity and Reality, where I read and reread the striking chapter on "Ir rationality". In my earlier researches into the origins of French Conven tionalism I came to know similar views, all apparently deriving from Emile Boutroux's doctoral thesis of 1874 De fa contingence des lois de la nature and his notes of the 1892-3 course he taught at the Sorbonne De ['idee de fa loi naturelle dans la science et la philosophie contempo raines. But never before was the full effect of the argument so suddenly clear as when I read Meyerson. On the same week I read, by sheer accident, Ernest Moody's two parts paper in the JHIof 1951, "Galileo and Avempace". Put near Meyerson's thesis, what Moody argued was a striking confirmation: it was the sheer irrationality of the Platonic tradition, leading from A vem pace to Galileo, which was the working conceptual force behind the notion of a non-appearing nature, active all the time but always sub merged, as it is embodied in the concept of void and motion in it.

The ArgumentThe inclusion of an item within a theory may be essential or accidental, and if the former then the explanation of its meaning and of its inclusion in the theory cannot be by accidental events and circumstances. Since all events and circumstances – be they social, political, religious, psychological, etc. – are accidental vis-à-vis the ideas they occasion, they cannot serve as explanation of these ideas. The only way to explain the ideas is by showing their essentiality to the theory rather than their importance to the people. Thus, the place of spirits and souls within seventeenth-century science is explained by Platonic ideology.This demands a concept of nature which is thoroughly efficient causative, and a concept of explanation which is thoroughly informative. This means that theories must explain any given effect by a cause which is separable from it and is conceptually heterogeneous to it. Such a nature and such an explanation are inherently paradoxical and irrational, which explains the preponderance of these traits in seventeenth-century science as created by Kepler, through Galileo and Descartes to Newton.The primary efficient-causal and explanatory agency is force, which is ontically distinct from matter and from the motion it causes in matter. Soul, spirit and active principle are mere variants of force. Thus, their presence in seventeenth-century science is explained only by their being conceptually essential to any Platonic philosophy of nature.

There is no evidence to suggest that even as late as January 1672, when Newton was elected a Fellow of the Royal Society, anyone had any inkling of his new theory of colours. His name exploded on the scientific scene as the inventor and constructor of a new kind of telescope—what later became known as the reflector. Had the erudition of the London virtuosi been a little broader, they would have known that in fact he was not the inventor of the telescope, even though the precise form he gave it was his. Not only was the idea a hundred years old, during which period it was repeatedly suggested by various writers, but also Newton himself took the idea straight from the most recent of these suggestions, namely that included in James Gregory's Optica promota of 1663. The situation becomes even more ironic when we realize that the new instrument was admired for wrong reasons and on merits that were far from Newton's intentions. Nevertheless, admired it was, and there was a good reason for this: Newton's instrument was in fact the first reflector actually to be constructed and, moreover, for a few weeks it performed quite well. Several astonomers became interested because of the high magnifying power relative to its dimensions.