VII TRUTH At the bottom of all philosophy, of all science and of all thinking, you will find the one all-inclusive question: How is man to tell truth from error? The ignorant man solves this problem in a very simple manner: he holds that whatever he believes, he knows; and that whatever he knows is true. This is the attitude of all amateur and professional theologians, politicians and other numbskulls of that sort. The pious old maid, for example, who believes in the doctrine of the immaculate conception looks upon her faith as proof, and holds that all who disagree with her will suffer torments in hell. Opposed to this childish theory of knowledge is the chronic doubt of the educated man. He sees daily evidence that many things held to be true by nine-tenths of all men are, in reality, false, and he is thereby apt to acquire a doubt of everything, including his own beliefs. At different times in the history of man, various methods of solving or evading the riddle have been proposed. In the age of faith it was held that, by his own efforts alone, man was unable, even partly, to distinguish between truth and error, but that he could always go for enlightenment to an infallible encyclopedia: the word of god, as set forth, through the instrumentality of inspired scribes, in the holy scriptures. If these scriptures said that a certain proposition was true, it was true, and any man who doubted it was either a lunatic or a criminal. This doctrine prevailed in Europe for many years and all who ventured to oppose it were in danger of being killed, but in the course of time the number of doubters grew so large that it was inconvenient or impossible to kill all of them, and so, in the end, they had to be permitted to voice their doubts unharmed. The first man of this new era to inflict any real damage upon the ancient churchly idea of revealed wisdom was Nicolas of Cusa, a cardinal of the Roman Catholic Church, who lived in the early part of the fifteenth century. Despite his office and his time, Nicolas was an independent and intelligent man, and it became apparent to him, after long reflection, that mere belief in a thing was by no means a proof of its truth. Man, he decided was prone to err, but in the worst of his errors, there was always some kernel of truth, else he would revolt against it as inconceivable. Therefore, he decided, the best thing for man to do was to hold all of his beliefs lightly and to reject them whenever they began to appear as errors. The real danger, he said, was not in making mistakes, but in clinging to them after they were known to be mistakes. It seems well nigh impossible that a man of Nicolas' age and training should have reasoned so clearly, but 'J. W. Draper, "A History of the Conflict Between Religion and Science;" New York, 1874. • Richard Falckenberg: "A History of Modern Philosophy," tr. by A. C. Armstrong, Jr.; New York, 1897; Chap. I. the fact remains that he did, and that all of modern philosophy is built upon the foundations he laid. Since his time a great many other theories of knowledge have been put forward, but all have worked, in a sort of circle, back to Nicolas. It would be interesting, perhaps, to trace the course and history of these variations and denials, but such an enterprise is beyond the scope of the present inquiry. Nicolas by no means gave the world a complete and wholly credible system of philosophy. Until the day of his death scholasticism was dominant in the world that he knew, and it retained its old hold upon human thought, in fact, for nearly two hundred years thereafter. Not until Descartes, in 1619, made his famous resolution "to take nothing for the truth without clear knowledge that it is such," did humanity in general begin to realize, as Huxley says, that there was sanctity in doubt. And even Descartes could not shake himself free of the supernaturalism and other balderdash which yet colored philosophy. He laid down, for all time, the emancipating doctrine that "the profession of belief in propositions, of the truth of which there is no sufficient evidence, is immoral "-a doctrine that might well be called the Magna Charta of human thought - but it should not be forgotten that he also laid down other doctrines and that many of them were visionary and silly. The philosophers after him rid their minds of the old ideas but slowly and there were frequent reversions to the ancient delusion that a man's mind is a function of his soul-whatever that may be and not of his body. It was common, indeed, for a philosopher to - 'T. H. Huxley: "Hume," preface; London, 1879. I set out with sane, debatable, conceivable ideas - and then to go soaring into the idealistic clouds. Only in our own time have men come to understand that the ego, for all its seeming independence, is nothing more than the sum of inherited race experience that a man's soul, his conscience and his attitude of mind are things he has inherited from his ancestors, just as he has inherited his two eyes, his ten toes and his firm belief in signs, portents and immortality. Only in our own time have men ceased seeking a golden key to all riddles, and sat themselves down to solve one riddle at a time. Those metaphysicians who fared farthest from the philosopher of Cusa evolved the doctrine that, in themselves, things have no existence at all, and that we can think of them only in terms of our impressions of them. The color green, for example, may be nothing but a delusion, for all we can possibly know of it is that, under certain conditions, our optic nerves experience a sensation of greenness. Whether this sensation of greenness is a mere figment of our imagination or the reflection of an actual physical state, is something that we cannot tell. It is impossible, in a word, to determine whether there are actual things around us, which produce real impressions upon us, or whether our idea of these things is the mere result of subjective impressions or conditions. We know that a blow on the eyes may cause us to see a flash of light which does not exist and that a nervous person may feel the touch of hands and hear noises which are purely imaginary. May it not be possible, also, that all Comte and Kant, for example. other sensations have their rise within us instead of without, and that in saying that objects give us impressions we have been confusing cause and effect? Such is the argument of those metaphysicians who doubt, not only the accuracy of human knowledge, but also the very capacity of human beings to acquire knowledge. It is apparent, on brief reflection, that this attitude, while theoretically admissible, is entirely impracticable, and that, as a matter of fact, it gives us no more substantial basis for intelligent speculation than the old device of referring all questions to revelation. To say that nothing exists save in the imagination of living beings is to say that this imagination itself does not exist. This, of course, is an absurdity, because every man is absolutely certain that he himself is a real thing and that his mind is a real thing, too, and capable of thought. In place of such cob-web spinning, modern philosophers - driven to it, it may be said, in parenthesis, by the scientists have gone back to the doctrine that, inasmuch as we can know nothing of anything save through the impressions it makes upon us, these impressions must be accepted provisionally as accurate, so long as they are evidently normal and harmonize one with the other. That is to say, our perceptions, corrected by our experience and our common sense, must serve as guides for us, and we must seize every opportunity to widen their range and increase their accuracy. For millions of years they have been steadily augmenting our store of knowledge. We know, for instance, that when fire touches us it causes an impression which we call pain and that this impression is invariably the same, and always leads to the same re |