What Is a Display ?

garded as scientific unless they could be expressed in numbers; Ernst Mach argued that the terms of a science must ultimately refer to sensations; P. W. Bridgeman held that scientific terms mean the operations involved in their application; and there have been those, like Einstein, who have opposed such reductionist views with what could be called constructivist approaches to the uses of concepts in science. But whatever the position taken about the meaning of meaning, science is seen as overcoming the vagaries of ordinary discourse by pinning meanings down with sharp definitions. At least such is supposed to be the case in the so-called hard sciences of physics and chemistry. Biology may be another matter; and although psychology has been recurrently preoccupied about problems of definition, it appears to have had only passing success in solving them. Ethology, however, sometimes gives the impression of being averse to definition, and even of making an ally of ambiguity. Its dealings in instinct, for example, have let vagueness and multiple meaning carry argument