I have spent, I fear, a great deal of time on what will appear to many as very irrelevant prolegomena. But the complete breakdown of the older views about nature and man, of the philosophies and theologies based not on observation but on an authority which is no authority, on unverifiable speculation, on superstition, and on what we would like to be so rather than on what happens to be so--the breakdown of all the commonly accepted basis for man’s view of himself and the universe, has made it necessary to go back to fundamentals if we are to see where we stand. Secondly, the progress of the biological and psychological sciences, as I have already pointed out, has considerably altered the outlook of those who pin their faith to the newer or scientific view of nature, the view which attempts constantly to refer speculations to reality, and to build on foundations which have been tested by experiment. The orthodox evolutionary view was that phenomena received in some degree an explanation if their origin from simpler phenomena could be demonstrated. As a matter of fact, reflection makes it clear that such an explanation is never complete. It is a very incomplete explanation of the properties of water to discover that it is composed of oxygen and hydrogen; or of those of humanity to discover that it is derived from lower forms of life. A precisely similar mistake is made by most psycho-analysts, who consider that an “explanation” of adult psychology is given by tracing in it effects of the events of childhood. In all such cases it is true that analysis is helped, but we are by no means exempted from further study of the later (and more complex) phenomena in and for themselves. Just as adult psychology is qualitatively different in various respects from childish psychology, so is man qualitatively different from lower organisms. Very few attempts have been made to carry over conceptions derived from sociology into biology.[19] But the converse, as we have seen, has often been true, and numerous writers--largely because purely biological are simpler than human phenomena--have been obsessed with the idea that the study of biology as such will teach us principles which can be applied directly and wholesale to human problems.