[30] On this subject, compare _A Theory of Time and Space_, by Mr. A.A. Robb (Camb. Univ. Press), which first suggested to me the views advocated here, though I have, for present purposes, omitted what is most interesting and novel in his theory. Mr. Robb has given a sketch of his theory in a pamphlet with the same title (Heffer and Sons, Cambridge, 1913). [31] "Natural Realism and Present Tendencies in Philosophy," _Proc. Arist. Soc._, 1908-1909, p. 165. [32] _Die Erfahrungsgrundlagen unseres Wissens_, p. 28. [33] Cf. _Principia Mathematica_, Vol. I, * 14, and Introduction, Chap. III. For the definition of _existence_, cf. * 14. 02. [34] Cf. Edwin B. Holt, _The Place of Illusory Experience in a Realistic World._ "The New Realism," p. 303, both on this point and as regards _seeing double_. IX ON THE NOTION OF CAUSE In the following paper I wish, first, to maintain that the word "cause" is so inextricably bound up with misleading associations as to make its complete extrusion from the philosophical vocabulary desirable; secondly, to inquire what principle, if any, is employed in science in place of the supposed "law of causality" which philosophers imagine to be employed; thirdly, to exhibit certain confusions, especially in regard to teleology and determinism, which appear to me to be connected with erroneous notions as to causality. All philosophers, of every school, imagine that causation is one of the fundamental axioms or postulates of science, yet, oddly enough, in advanced sciences such as gravitational astronomy, the word "cause" never occurs. Dr. James Ward, in his _Naturalism and Agnosticism_, makes this a ground of complaint against physics: the business of those who wish to ascertain the ultimate truth about the world, he apparently thinks, should be the discovery of causes, yet physics never even seeks them. To me it seems that philosophy ought not to assume such legislative functions, and that the reason why physics has ceased to look for causes is that, in fact, there are no such things. The law of causality, I believe, like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm. In order to find out what philosophers commonly understand by "cause," I consulted Baldwin's _Dictionary_, and was rewarded beyond my expectations, for I found the following three mutually incompatible definitions:-- "CAUSALITY. (1) The necessary connection of events in the time-series.... "CAUSE (notion of). Whatever may be included in the thought or perception of a process as taking place in consequence of another process....