The Justification of Doubt

Philosophers of all ages have insisted that knowing is one of the most important activities of man. Most of them have attempted to explain how this mysterious activity occurs, and to furnish a method for sifting the grains of indubitable knowledge from the chaff of supposed truth entertained by the human mind. This enterprise and inquiry is technically known as epistemology. Some philosophers have been so bold as to claim that ideally, at least, man’s intellect could ascend the ladder of knowledge to a vision of the principles of all creation. Omitting the complete sceptics, we find another school of thought who would limit our knowledge to the sense data which can be immediately perceived. These doubts have never been satisfactorily resolved in modern philosophy, though many solutions have been attempted in terms of psychology, semantics, animal faith, common sense, and so on. The semantic school and the logical positivists are two examples receiving much popular notice at present. It is into this situation that Bertrand Russell modestly and tentatively dares to tread with “An Inquiry into Meaning and Truth” to see what fragments of certainty he can save from the doubt-demolished edifice of human knowledge. For Mr. Russell, truth is of two kinds, and consequently two different sciences of truth are required to deal with the correspondingly diverse problems. First, there is purely formal truth, based on the consistency of logical relations between logical propositions. This part of the problem, for Mr. Russell, has been adequately handled by the science of modern logic; indeed he has been an active and original contributor to this field of knowledge. But merely logical truth is obviously not sufficient for practical human purposes, since it is not concerned with any knowledge of the truth of fact, but only with formal operations performed on symbols according to logical rules. Thus, for example, in pure logic, the following proposition is true: If “two times two equals five” then “snow is black.”

Recognizing this insufficiency of merely logical truth, Mr. Russell in this book addresses himself to the problems involved in establishing the second kind of truth: our knowledge of the truth of fact, of epistemological as distinguished from logical truth. He proposes to do this by analyzing out the “basic propositions” which have a direct relation to our immediate experiences, and thereby setting up the psychological foundations of logic. Such basic propositions signify “true knowledge” when each of their terms can be verified in an immediate sense experience. Russell extends this immediate knowledge beyond the momentary perception by appealing to memory; and this individual knowledge based on memory is in turn saved from its subjectivity and extended to social truth by appealing to a general behavioristic viewpoint. For example, I may be said to know the “meaning” of a word or basic sentence if I use it appropriately and act appropriately upon hearing it. Consequently, other persons, by observing my behavior (linguistic and otherwise), have an objective ground for sharing in the “meaning” of the sentence and of testing the objective correspondence between the sentence and the direct experience. The momentary perception thus becomes the touchstone and criterion of certainty by which all other degrees of certitude are measured. This minimum knowledge gives Mr. Russell grounds for hoping that some day “inductive evidence may make an empirical generalization possible,” and for believing that we can go beyond a knowledge of mere words and syntax to a considerable knowledge of the world and its structure.

“The net result is to substitute articulate hesitation for inarticulate certainty.” Apparently, the articulate certainty demanded by the human mind is to be found only in the operations of symbolic logic. The mind may manipulate symbols and words in a grammatical ordering of names; but percepts are substituted for intelligible concepts. Thus rational insight into universal principles is reduced to animal behavior and habit. On the positive side it may be said that Mr, Russell has made memory possible and history plausible.