Truth that has been merely learned is like an artificial limb, a false tooth, a waxen nose; at best, like a nose made out of another's flesh; it adheres to us only because it is put on. But truth acquired by thinking of our own is like a natural limb; it alone really belongs to us. This is the fundamental difference between the thinker and the mere man of learning. The intellectual attainments of a man who thinks for himself resemble a fine painting, where the light and shade are correct, the tone sustained, the color perfectly harmonized; it is true to life. On the other hand, the intellectual attainments of the mere man of learning are like a large palette, full of all sorts of colors, which at most are systematically arranged, but devoid of harmony, connection and meaning.
Reading is thinking with some one else's head instead of one's own. To think with one's own head is always to aim at developing a coherent whole—a system, even though it be not a strictly complete one; and nothing hinders this so much as too strong a current of others' thoughts, such as comes of continual reading. These thoughts, springing every one of them from different minds, belonging to different systems, and tinged with different colors, never of themselves flow together into an intellectual whole; they never form a unity of knowledge, or insight, or conviction; but, rather, fill the head with a Babylonian confusion of tongues. The mind that is over-loaded with alien thought is thus deprived of all clear insight, and is well-nigh disorganized. This is a state of things observable in many men of learning; and it makes them inferior in sound sense, correct judgment and practical tact, to many illiterate persons, who, after obtaining a little knowledge from without, by means of experience, intercourse with others, and a small amount of reading, have always subordinated it to, and embodied it with, their own thought.
The really scientific thinker does the same thing as these illiterate persons, but on a larger scale. Although he has need of much knowledge, and so must read a great deal, his mind is nevertheless strong enough to master it all, to assimilate and incorporate it with the system of his thoughts, and so to make it fit in with the organic unity of his insight, which, though vast, is always growing. And in the process, his own thought, like the bass in an organ, always dominates everything and is never drowned by other tones, as happens with minds which are full of mere antiquarian lore; where shreds of music, as it were, in every key, mingle confusedly, and no fundamental note is heard at all.
Those who have spent their lives in reading, and taken their wisdom from books, are like people who have obtained precise information about a country from the descriptions of many travellers. Such people can tell a great deal about it; but, after all, they have no connected, clear, and profound knowledge of its real condition. But those who have spent their lives in thinking, resemble the travellers themselves; they alone really know what they are talking about; they are acquainted with the actual state of affairs, and are quite at home in the subject.
The thinker stands in the same relation to the ordinary book-philosopher as an eye-witness does to the historian; he speaks from direct knowledge of his own. That is why all those who think for themselves come, at bottom, to much the same conclusion. The differences they present are due to their different points of view; and when these do not affect the matter, they all speak alike. They merely express the result of their own objective perception of things. There are many passages in my works which I have given to the public only after some hesitation, because of their paradoxical nature; and afterwards I have experienced a pleasant surprise in finding the same opinion recorded in the works of great men who lived long ago.
The book-philosopher merely reports what one person has said and another meant, or the objections raised by a third, and so on. He compares different opinions, ponders, criticises, and tries to get at the truth of the matter; herein on a par with the critical historian. For instance, he will set out to inquire whether Leibnitz was not for some time a follower of Spinoza, and questions of a like nature. The curious student of such matters may find conspicuous examples of what I mean in Herbart's Analytical Elucidation of Morality and Natural Right, and in the same author's Letters on Freedom. Surprise may be felt that a man of the kind should put himself to so much trouble; for, on the face of it, if he would only examine the matter for himself, he would speedily attain his object by the exercise of a little thought. But there is a small difficulty in the way. It does not depend upon his own will. A man can always sit down and read, but not—think. It is with thoughts as with men; they cannot always be summoned at pleasure; we must wait for them to come. Thought about a subject must appear of itself, by a happy and harmonious combination of external stimulus with mental temper and attention; and it is just that which never seems to come to these people.
This truth may be illustrated by what happens in the case of matters affecting our own personal interest. When it is necessary to come to some resolution in a matter of that kind, we cannot well sit down at any given moment and think over the merits of the case and make up our mind; for, if we try to do so, we often find ourselves unable, at that particular moment, to keep our mind fixed upon the subject; it wanders off to other things. Aversion to the matter in question is sometimes to blame for this. In such a case we should not use force, but wait for the proper frame of mind to come of itself. It often comes unexpectedly and returns again and again; and the variety of temper in which we approach it at different moments puts the matter always in a fresh light. It is this long process which is understood by the term a ripe resolution. For the work of coming to a resolution must be distributed; and in the process much that is overlooked at one moment occurs to us at another; and the repugnance vanishes when we find, as we usually do, on a closer inspection, that things are not so bad as they seemed.
This rule applies to the life of the intellect as well as to matters of practice. A man must wait for the right moment. Not even the greatest mind is capable of thinking for itself at all times. Hence a great mind does well to spend its leisure in reading, which, as I have said, is a substitute for thought; it brings stuff to the mind by letting another person do the thinking; although that is always done in a manner not our own. Therefore, a man should not read too much, in order that his mind may not become accustomed to the substitute and thereby forget the reality; that it may not form the habit of walking in well-worn paths; nor by following an alien course of thought grow a stranger to its own. Least of all should a man quite withdraw his gaze from the real world for the mere sake of reading; as the impulse and the temper which prompt to thought of one's own come far oftener from the world of reality than from the world of books. The real life that a man sees before him is the natural subject of thought; and in its strength as the primary element of existence, it can more easily than anything else rouse and influence the thinking mind.
After these considerations, it will not be matter for surprise that a man who thinks for himself can easily be distinguished from the book-philosopher by the very way in which he talks, by his marked earnestness, and the originality, directness, and personal conviction that stamp all his thoughts and expressions. The book-philosopher, on the other hand, lets it be seen that everything he has is second-hand; that his ideas are like the number and trash of an old furniture-shop, collected together from all quarters. Mentally, he is dull and pointless—a copy of a copy. His literary style is made up of conventional, nay, vulgar phrases, and terms that happen to be current; in this respect much like a small State where all the money that circulates is foreign, because it has no coinage of its own.
Mere experience can as little as reading supply the place of thought. It stands to thinking in the same relation in which eating stands to digestion and assimilation. When experience boasts that to its discoveries alone is due the advancement of the human race, it is as though the mouth were to claim the whole credit of maintaining the body in health.