“In the use of language, for instance, we depend on the fact that names have been given to objects, qualities, and relations, which fix certain similarities and differences in the flow of experience as boundaries containing it, dividing it, directing it. Whenever we describe, we class things or properties or events together or apart on the basis of the similarities and differences marked by the words we choose. Consequently, to the extent that science begins with description, it begins with comparison.
But no two things, no two qualities, no two events are alike in all respects, or alike in none. Any description singles out some similarities and differences to the exclusion of others, which could be the basis of alternative descriptions. Consequently, a demand for a complete description of anything amounts to a contradiction in terms. A demand for a pure description would be equally incoherent, for, of necessity, the similarities and differences that we pick out when we describe anything will depend on what we intend the description for, our expectations about the matter in question, considerations of relevance to some focus of interest, and other prior assumptions. Comparison necessarily assumes perspective.
Perspectives differ among sciences, among schools within a science, and among scientists within a school. Consequently, the history of science is no less littered with controversy and confusion than the history of philosophy, art, or politics. The conception that we have of something is often so deeply and firmly embedded in our minds that we cannot even entertain the possibility of an alternative. Such a conception governs our very perceiving of the thing; we cannot see it any other way and “know” that that is the way it really is. Anyone who claims otherwise we regard as purblind, or perverse, or just plain crazy. The closed-mindedness that can result from this sort of conviction is one of the sources of what my teacher, Niko Tinbergen, used to call “nothing-but-ism”: behavior is nothing but reflexes; morality is nothing but self-interest; everything is nothing but matter in motion.”
Colin G Beer