The Gifford lectures delivered in the University of St. Andrews in the year 1922
Lecture II. Mental and non-mental
§ X. Acknowledgment.
...Now for better or worse my notion of philosophy is that, while it involves the contributions of science in all departments, it should seek to express a constructive scheme of the world-a consistent scheme which is conceived at a level of reflective thought that supplements, though it does not supersede, science.
There must be nothing in this scheme which is discrepant with science ; but, on this understanding, there may be constitutive features which complete the otherwise incomplete delivery of strictly scientific thought. That, I think, has always been the aim of philosophy. It will, I feel sure, continue to be its aim. It seeks to develop a constructive creed and not only a working policy.
In any case, I want to nail my colours to the mast. In credal terms, I believe in a physical world and in systems of events from which there is what I have called advenient influence. But, with Mr. Russell and Mr. Nunn, I question whether the existence of such a physical world is susceptible of proof. I use, therefore, the word “ acknowledgment ” for the credal acceptance of a physical world, existent in its own right, independently of any sensory acquaintance therewith. This world, or any “ thing ” therein, is beyond appearance ; it is that to which appearances are projiciently referred. It is the skeleton which we clothe with the flesh of objective experience.