It is difficult to say just what effects this change in thought, when apparently one has engaged in no reflection during the interval. The attempted solution probably gives a certain “set” to our minds. Without being aware of it we observe facts relating to our problem. Ideas which occur to us in other connections are unconsciously seen in their bearing on the unsolved question. In short, “those proclivities of thought which have probably been caused unawares by experience” make themselves felt.
It may be imagined that if we think too much we will be liable permanently to injure our mighty intellects. This has sometimes happened. But there is no serious danger of it. Thinking on one useful subject for a long while will not hurt you any more than thinking on a thousand different useless subjects for the same period. But of course you should not try to concentrate when you are sleepy, when you have a headache, when some other bodily pain distracts your attention, or when your mind is in any way tired. If you attempt to concentrate at these times you will endanger your mental and physical health. Not only this, but the thinking done during such periods will be of such poor quality that it will be practically useless if not harmful. This applies even to cases where mental fatigue is almost inappreciable. Thinking done in the evening seldom approaches in efficacy the thinking done in the first hours of the morning. But you should always make sure your mind is actually tired. It may merely be tired of a particular subject.
An objection of a different kind may be raised against concentrating at every opportunity. It has often been noticed that names have been recalled and problems solved when we were thinking of something else. It may be urged that such solutions would not have occurred when concentrating, because the exact associations which led up to them would not have been present. This is occasionally true. But there are still reasons why I must maintain my position. No matter how well a man may have trained himself to concentrate, there will always be short periods when his mind will wander, and these will suffice for any accidental associations. Moreover, the fact that these mind wandering periods occasionally do good does not excuse their existence. The most fallacious ideas, the most demoniacal practices, the most despicable characters of history, have occasionally done good. The fact is that for every useful association which occurs during mind wandering, ten associations just as useful will occur during concentration. The only reason useful mind wandering associations appear frequent is that they are unexpected, therefore more noticed when they come.
It has been frequently said that many of the world’s greatest inventions were due to accident. In a sense this is true. But the accident was prepared for by previous hard thinking. It would never have occurred had not this thinking taken place. It is said that the idea of gravitation came to Newton because an apple fell on his head. Perhaps. But apples had been falling ever since there were apple trees, and had probably been falling on men’s heads ever since men had acquired the habit of getting their heads in the way. The idea of the steam engine is supposed to have come to Watt while observing a tea kettle. But how many thousands before him had not seen steam coming out of kettles? The idea of the pendulum for regulating time occurred to Galileo from observing a swinging lantern in a cathedral. Think how many others must have seen that lantern swinging! It is probable that in all these cases the invention or idea had been prepared for, had been all but formed, by downright hard thinking in previous periods of concentration. All that was needed was the slightest unusual occurrence to make the idea complete and conscious. The unusual occurrence, the accident, which has so often received the credit for the invention or the idea, merely made it come sooner, for with the thinking these men did, it was bound to come eventually. . . .
Of course I really do not seriously expect anybody to concentrate at every opportunity. I don’t myself. I merely wanted to establish the fact that it’s the best thing. But every man, even the tired business variety, should set aside at least half an hour a day, or three and a half hours a week. I realize what a great hardship it is for some people to devote one-forty-eighth of their time to such a useless pastime as thinking. But if they will make the sacrifice for seven consecutive days they will find themselves bearing up nobly at the end.
There is even a possibility that they may be encouraged to extend the time.
V PREJUDICE AND UNCERTAINTY
“From time to time there returns upon the cautious thinker, the conclusion that, considered simply as a question of probabilities, it is decidedly unlikely that his views upon any debatable topic are correct. ‘Here,’ he reflects, ‘are thousands around me holding on this or that point opinions differing from mine—wholly in most cases; partially in the rest. Each is as confident as I am of the truth of his convictions. Many of them are possessed of great intelligence; and, rank myself high as I may, I must admit that some are my equals—perhaps my superiors. Yet, while every one of us is sure he is right, unquestionably most of us are wrong. Why should not I be among the mistaken? True, I cannot realize the likelihood that I am so. But this proves nothing; for though the majority of us are necessarily in error, we all labor under the inability to think we are in error. Is it not then foolish thus to trust myself? When I look back into the past, I find nations, sects, philosophers, cherishing beliefs in science, morals, politics, and religion, which we decisively reject. Yet they held them with a faith quite as strong as ours; nay—stronger, if their intolerance of dissent is any criterion. Of what little worth, therefore, seems this strength of my conviction that I am right? A like warrant has been felt by men all the world through; and, in nine cases out of ten, has proved a delusive warrant. Is it not then absurd in me to put so much faith in my judgments?’ ”[9]
I trust the reader will pardon this second rather extended quotation from Herbert Spencer, but the thought expressed must be kept in mind if we are to approach our present subject in the proper spirit. . . .
Our subject is prejudice. Our object is to free ourselves as much as possible from our own prejudices. But before we can get rid of a thing it is first necessary to recognize that thing when we see it.