Can We Be Sure of the Truth of Any General Principle?

Bertrand Russell on Truth

Can We Be Sure of the Truth of Any General Principle?

In Problems of Philosophy, Bertrand Russell addresses the subject of induction. It forms the basis of his assertions related to knowledge and truth beyond experience or acquaintance. In general, he posits that we draw inferences based upon general principles and expectations to make meaning of our world beyond the range of our immediate experience and formulate truth. In order to draw an inference, it must be known that "some sort of thing, A, is a sign of the existence of some other sort of thing, B" (Russell 35). The existence of night usually signifies that it was preceded by day. Russell offers that we make these inferential judgments on a constant basis, even in situations where they are improbable.

Russell uses the general expectation that the sun will rise as the basis of his arguments on induction (32). That each new day will bring the sun is a universally accepted truth. The basis for this belief, for most people, is that the sun has always risen. Our past experiences, therefore, form our understanding of our future. We continue to believe that a certain principle will be true in the future only because that argument is supported by experience -- so we assume the inductive principle. We believe that "everything that has happened or will happen is an instance of some general law to which there are no exceptions" (Russell 33). We accept the inductive principle based on its "intrinsic evidence" or "forgo all justification of our expectations about the future" (Russell 35).

He also tackles our knowledge of general principles, which function very similarly to the principle of induction. The truth of select principles cannot be proven or refuted, yet can achieve the same degree of certainty as knowledge by direct experience (Russell 37). When we practice induction, "we realize some particular application of the principle, and then we realize that the particularity is irrelevant and that there is a generality which may equally truly be affirmed" (Russell 39).

One simple example of this realization takes place with the mathematical formula "four plus four is eight." First, we grasp one instance of the statement's truth, and then we see that it applies in other instances as well. Then, sooner or later, we are able to see the general truth that the statement holds true for just about any particular case. According to Russell, the same practice occurs with logical principles. Our experience and knowledge tells us that if the premises in an argument are true, then the conclusion is also true. Russell offers the observation that all of our knowledge rests, in part, on experience. We better understand this through the illustration that in order to grasp the a priori of "four and four are eight," we must first experience at least one instance.

Our belief in the truth of any principle follows the 'Laws of Thought' (Russell 38). They are the law of identity (whatever is, is), the law of contradiction (nothing can both be and not be) and the law of excluded middle (everything must either be or not be). In other words, we have relative certainty about some things; however, as we examine closer, contradictions can arise and alter our thoughts about what is true and what is not. We use our present experiences to form the basis of our beliefs, and from this, we derive knowledge. Yet, our thoughts may be incorrect and require still further analysis. In his infamous table example, Russell would have us consider that:

"When, in ordinary life, we speak of the colour of the table, we only mean the sort of colour which it will seem to have to a normal spectator from an ordinary point-of-view under usual conditions of light. But the other colours which appear under other conditions have just as good a right to be considered real; and therefore, to avoid favouritism, we are compelled to deny that, in itself, the table has any one particular colour" (3).