units of speech, the former as an abstracted minimum, the latter as the esthetically satisfying embodiment of a unified thought.  The actual formal units of speech, the words, may on occasion identify themselves with either of the two functional units; more often they mediate between the two extremes, embodying one or more radical notions and also one or more subsidiary ones.  We may put the whole matter in a nutshell by saying that the radical and grammatical elements of language, abstracted as they are from the realities of speech, respond to the conceptual world of science, abstracted as it is from the realities of experience, and that the word, the existent unit of living speech, responds to the unit of actually apprehended experience, of history, of art.  The sentence is the logical counterpart of the complete thought only if it be felt as made up of the radical and grammatical elements that lurk in the recesses of its words.  It is the psychological counterpart of experience, of art, when it is felt, as indeed it normally is, as the finished play of word with word.  As the necessity of defining thought solely and exclusively for its own sake becomes more urgent, the word becomes increasingly irrelevant as a means.  We can therefore easily understand why the mathematician and the symbolic logician are driven to discard the word and to build up their thought with the help of symbols which have, each of them, a rigidly unitary value.

But is not the word, one may object, as much of an abstraction as the radical element?  Is it not as arbitrarily lifted out of the living sentence as is the minimum conceptual element out of the word?  Some students of language have, indeed, looked upon the word as such an abstraction, though with very doubtful warrant, it seems to me.  It is true that in particular cases, especially in some of the highly synthetic languages of aboriginal America, it is not always easy to say whether a particular element of language is to be interpreted as an independent word or as part of a larger word.  These transitional cases, puzzling as they may be on occasion, do not, however, materially weaken the case for the psychological validity of the word.  Linguistic experience, both as expressed in standardized, written form and as tested in daily usage, indicates overwhelmingly that there is not, as a rule, the slightest difficulty in bringing the word to consciousness as a psychological reality.  No more convincing test could be desired than this, that the naive Indian, quite unaccustomed to the concept of the written word, has nevertheless no serious difficulty in dictating a text to a linguistic student word by word; he tends, of course, to run his words together as in actual speech, but if he is called to a halt and is made to understand what is desired, he can readily isolate the words as such, repeating them as units.  He regularly refuses, on the other hand, to isolate the radical or grammatical element, on the ground that it “makes no sense."[6] What, then, is the objective criterion of the word?  The speaker and hearer feel the word, let us grant, but how shall we justify their feeling?  If function is not the ultimate criterion of the word, what is?