When we map out the whole region of Truth-claim or Formal Truth, we find that it contains (1) lies, (2) errors, (3) methodological fictions, (4) methodological assumptions, (5) postulates, (6) validated truths, (7) axioms, and (8) jokes.
Most philosophers in fact would not only ignore his eighth category, but would neglect his first and second, accepting any statement that claimed to be true and devoting themselves to the study of its logical implications. But the pragmatist is more interested in finding out how and in what way an assertion comes to be called true and how it makes good its claim after it has been asserted. As Schiller puts it:[5]
What then is common to all sorts of Truth and Error, and renders them species of a common genus? Nothing but their psychological side; "truth" is the proper term for what satisfies, "error" for what thwarts, a human purpose in cognitive activity.
The difference between Truth and Error, therefore, is ultimately one in value. The "true" way of conceiving an object or judging a situation is simply the way most valuable for our purpose; the "false" way is one which is, at least relatively, worthless. "Truth" is a eulogistic, "error" a dyslogistic, way of valuing a cognitive situation.
Truth and Error therefore are continuous, as history shows. Either may develop out of the other, and both are rooted in the same problems of knowing, which are ultimately problems of living. The "truths" of one generation become the "errors" of the next, when it has achieved more valuable and efficient modes of interpreting and manipulating the apparent "facts", which the new "truths" are continuously transforming. And conversely, what is now scouted as "error" may hereafter become the fruitful parent of a long progeny of "truths."
It follows also that (as every examiner who marks a paper knows) Truth and Error admit of quantitative differences. Both can vary in importance, and can attain (or fail of) their purpose to a greater or a less degree. But neither is absolute. An answer to a question is in general called true, if it is true enough for the purpose in hand. But this does not preclude a greater exactitude if (for a different purpose) it should be required. It is a true answer to the question—"when do you leave?" to reply "to-morrow"; but if necessary I can specify the train I go by. Thus the demand for absolute exactness is both humanly unnecessary and scientifically unmeaning. Indeed a degree of accuracy higher than the situation demands would be irrational. No one wants to know the height of a mountain in millimeters, and if he did, he could not ascertain it, because his methods would not measure fine enough. Scientific truths are infinitely perfectible, but never absolute.[6]
Now if philosophers are wise, they will accept this sort of truth, and admit that any truth is "absolute" enough so soon as it is equal to the demands made upon it, while none must ever be so absolute as to become incorrigible and incapable of further growth.
A human factor, an element of personal desire, enters into all our thinking; otherwise why should we bother to think? Even our most abstract and general theorems have a hidden Hinterland of subconscious motives, limitations, and conditions.
The abstract statement that "two and two make four" is always incomplete. We need to know to what "twos" and "fours" the dictum is applied. It would not be true of lions and lambs, nor of drops of water, nor of pleasures and pains.[7]
This suppressed context of thought is of course largely personal, and with it is suppressed the human interest of philosophy. Hence the endeavor to drag it to light was very properly called Humanism. Schiller conceives every thought as some one's experiment for which he is responsible.
"Every thought", he says, "is an act and even the most 'theoretical' assertions are made to gratify an interest." He finds in the present war a most unpleasant confirmation of his theory that thought is subordinate to action and never free from human volitional influence:[8]
If only philosophers could be got to face the facts of actual life, could any of them fail to observe the enormous object-lesson in the truth of pragmatism which the world has been exhibiting in the present crisis? Everywhere the "truths" believed in are relative to the nationality and sympathies of their believers. It is, indeed, lamentable that such an orgy of the will to believe should have been needed to illustrate the pragmatic nature of truth, but who will dispute that for months say 999 persons out of 1000 have been believing what they please, and consciously or unconsciously making it "true" with a fervor rarely bestowed even by the most ardent philosophers on the most self-evident truths? No improbability, no absurdity, no atrocity has been too great to win credence, and the uniformity of human nature has been signally attested by the way in which the same stories (mutatis mutandis) have been credited on both sides.
Since the controversy over pragmatism hinges on this theory of truth, I will quote in condensed form what Schiller says in his discussion with Miss Stebbing:[9]
It is an inevitable corollary of the belief in absolute truth that absolute truth cannot find lodgment in human mind, nor be attained by way of human science. We were led, therefore, to examine how in fact belief in the accepted "truths" grew up. We found that every thought was essentially a personal experiment that might succeed or fail, and that whether it did or not depended on its consequences. But it seemed clear that "true" was the term appropriated by language to the success, as false was to failure, of such experiments. Of course both "success" and "truth" are relative terms. Absolute "success" is found as little as absolute "truth" and for the same reason. All "truths" remain (preferred) truth-claims and retain an infinite appetite for assimilating further confirmation.
But there does come a point, alike in the individual's experience and in social opinion at any time, at which it seems that certain truth-claims have received confirmation enough to make them pragmatically certain. These form the reigning truths. But they never form a closed oligarchy or an immutable system. Merit can force its way into their ranks, and inefficiency entails degradation. Thus, though their position is (psychologically) unchallenged, it is never (logically) unchallenged. So it can not be said that because they work they are absolutely true. They are called true because they work, and there is no sense in calling anything true for any other reason; but the progress of knowledge may nevertheless supersede them at the next step.