ABSTRACT
TH E disagreement or even distaste and scorn which many modem philosophers evince towards theories such as I am putting forward here probably have their origin in rather deep-lying disagreements about what constitutes a convincing argument. Philosophical thinkers have, in the last few decades, been profoundly influenced by many advances in modem science. The advances which have made most impression on them have been those in the physical sciences. Open any book of the present day dealing with epistemology or the general problems of philosophy, and you will find a discussion of pointer readings, the theory of relativity, the quantum theory, the indeterminacy principle, and so on. These are undoubtedly exceedingly important matters, but one would have thought them somewhat remote from the general activities of human beings, except in the very special field of the quantitative analysis of the behaviour of material bodies. Man is, after all, a biological entity. It is only in his most generalized characteristics, which he shares with sticks and stones, that he is a part of the subject matter of physics or chemistry. In his full being-or at least if we do not wish to beg the question, over a much wider range of his being-he falls within the province of biology. There are three currents of thought arising within biology which seem to me much more relevant to epistemology and general philosophy than anything that physics has or could discover about the behaviour of the ultimate units into which matter can be analysed. Two of these points relate to the subject matter of thought; the third to its logical structure.
