III. THE PLACE OF HYPOTHESIS IN

EXPEEIMENTAL SCIENCE. 1 By J. M. EIGG. THE following pages are intended to establish (1) that ] hypothesis is the principal organon of discovery in experi- I mental science ; (2) that hypothesis is based on analogy ; (3) that scientific hypotheses are not empirically verifiable. I shall then proceed to enunciate what I conceive to be the postulates of experimental science and the rationale of verifi- cation, and indicate briefly a view of the relation between v physics and metaphysics. That hypothesis is the principal organon of discovery in experimental science will doubtless seem a hard saying to not a few. The celebrated " Hypotheses non fingo " of Newton seems to act upon many thinkers like a charm ; they do not see that the emphasis is to be laid upon the fingo. They regard hypothesis as at best but a doubtful auxiliary to observation and experiment, and conceive that the main occupation of experimental science consists in establishing, by what are known as the experimental methods, the existence of invariable relations of coexistence, ante- ^ cedence and sequence between phenomena. It is not neces- sary for me to dispute the possibility of establishing by observation and experiment the existence of relations which in a certain sense are invariable. This at present I am con- cerned neither to affirm nor to deny. I contend, however, that when established such relations do not amount to laws of nature. In the first place it must be remarked that an uniformity of coexistence or of antecedence and sequence may mean either (1) an observed uniformity or (2) an hypothetical uniformity. So far, however, as laws of nature may consist of hypothetical uniformities, it is clear that the experimental methods alone are powerless to discover them. On the other hand, it can, I think, be demonstrated that no relations of coexistence, antecedence and sequence that are not hypo- thetical are in the strict sense laws of nature. If by uniformities of relation we are to understand merely 1 The substance of this paper was read before the Philosophical Society on 30th November, 1886.