ABSTRACT
We have been considering hitherto either the universe as a whole, or characteristics in which all parts of the universe are alike. What is said in astronomy and physics, if true, is completely neutral, in the sense that it has no special relation to ourselves or to our spatio-temporal neighbourhood. But we must now turn our attention to more parochial matters. There are things that we can know about our own planet and its parasites which we cannot know about other regions. It may be that life exists elsewhere, or that, in some remote nebula, there is something which, while not life as we know it, is equally complex and equally different from the inorganic substances known to us. But although this may be the case, there is no positive reason to suppose that it is; all that we know about life we know from observations on or very near the surface of the earth. In the scientific study of life we are turning our backs on the magnificent vistas of astronomy, and abandoning the search for the minute and intimate knowledge of structure that is to be derived from atomic theory.
