(Sets forth the fact that knowledge is freedom and ignorance is slavery, and what science means to the people.) We have now completed a brief survey of the mind and its powers. Whatever we may have proved or failed to prove, this much we may say with assurance: the reader who has followed our brief sketch attentively has been disabused of any idea he may have held that he knows it all; and this is always the first step towards knowledge.
The mind is the instrument whereby our race has lifted itself out of beasthood. It is the instrument whereby we hold ourselves above the forces which seek to drag us down, and whereby we shall lift ourselves higher, if higher we are to go. How shall we protect this precious instrument? How shall we complete our mastery of it? What are the laws of the conduct of the mind?
The process of the mind is one of groping outward after new facts, and digesting and assimilating them, as the body gropes after and digests and assimilates food. The senses bring us new impressions, and we take these and analyze them, tear them into the parts which compose them, compare them with previous sensations, recognize difference in things which seem to be alike, and resemblances in things which seem to be different; we classify them, and provide them with names, which are, as it were, handles for the mind to grasp. Above all, we seek for causes; those chains of events which make what we know as order in the world of phenomena. And when the mind has what seems to be a cause, it proceeds to test it according to methods it has worked out, the rules and principles of experimental science.
It is a comparatively small number of sensations which the body brings to the mind of itself; it is a narrow world in which we should live if our minds adopted a passive attitude toward life. But some minds possess what we call curiosity; they set out upon their own impulse to explore life; they discover new laws and make new experiences and new sensations for themselves. The mind forms an idea, and at first, after the fashion of the ancient Greek philosophers, it glorifies that idea and sets it in the seat of divinity. But presently comes the empirical method, which refuses authority to any idea unless it can stand the test of experiment, and prove that it corresponds with reality. Nowadays the thinker amasses his facts, and forms a theory to explain them, and then proceeds to try out this theory by the most rigid method that he or his critics can devise. If the theory doesn't "work"—that is, if it doesn't explain all the facts and stand all the tests—it is thrown away like a worn-out shoe. So little by little a body of knowledge is built up which is real knowledge; which will serve us in our daily lives, which we can use as foundation-stones in the structure of our civilization.
By this method of research man is expanding his universe beyond anything that could have been conceived in the pre-scientific days. Hour by hour, while we work and play and sleep, the mind of our race is discovering new worlds in which our posterity will dwell. For uncounted ages man walked upon the earth, surrounded by infinite swarms of bacterial life of whose existence he never dreamed. The invisible rays of the spectrum beat upon him, and he knew nothing of what they did to him, whether good or evil. He lifted his head and saw vast universes of suns, in comparison with which his world was a mere speck of dust; yet to him these universes were globes or lanterns which some divinity had hung in the sky.
One of the most fascinating illustrations of how the mind runs ahead of the senses is the story of the planet Uranus, which, less than two hundred years ago, had never been beheld by the eye of man. A mathematician seated in his study, working over the observations of other planets, their motions in relation to their mass and distance, discovered that their behavior was not as it should be. At certain times none of them were in quite the right place, and he decided that this variation must be due to the existence of an unknown body. He worked out the problem of what must be the mass and the exact orbit of this body, in order for it to be responsible for the variations observed; and when he had completed these calculations, he announced to the astronomical world, "Turn your telescopes to a certain spot in the heavens at a certain minute of a certain night, and you will find a new planet of a certain size." And so for the first time the human senses became aware of a fact, which by themselves they might not have discovered in all eternity.
Now, the importance of exact knowledge concerning a new planet may not be apparent to the ordinary man; but if the thing which is discovered is, for example, an unknown ray which will move an engine or destroy a cancer, then we realize the worthwhileness of research, and the masters of the world's commerce are willing to give here and there a pittance for the increase of such knowledge. But men of science, who have by this time come to a sense of their own dignity and importance, understand that there is no knowledge about reality which is useless, no research into nature which is wasted. You might say that to describe and classify the fleas which inhabit the bodies of rats and ground-squirrels, and to study under the microscope the bacteria which live in the blood of these fleas—that this would be an occupation hardly worthy of the divinity that is in man. But presently, as a result of this knowledge about fleas and flea diseases being in existence and available, a bacteriologist discovers the secret of the dread bubonic plague, which hundreds of times in past history has wiped out a great part of the population of Europe and Asia.
Mark Twain tells in his "Connecticut Yankee" how his hero was able to overcome the wizard Merlin, because he knew in advance of an eclipse of the sun. And this was fiction, of course; but if you prefer fact, you may read in the memoirs of Houdin, the French conjurer, how he was able to bring the Arab tribes into subjection to the French government by depriving the great chieftains of their strength. He gathered them into a theatre, and invited their mighty men upon the stage, and there was an iron weight, and they were able to lift it when Houdin permitted, and not to lift it when he forbade. These noble barbarians had never heard of the electro-magnet, and could not conceive of a force that could operate through a solid wooden floor beneath their feet.
Such things, trivial as they are, serve to illustrate the difference between ignorance and knowledge, and the power which knowledge gives. The man who knows is godlike to those who do not know; he may enslave them, he may do what he pleases with their lives, and they are powerless to help themselves. Anyone who would help them must begin by giving them knowledge, real knowledge. There is no such thing as freedom without knowledge, and it must be the best knowledge, it must be new knowledge; he who goes against new knowledge armed with old knowledge is like the Chinese who went out to meet machine-guns with bows and arrows, and with umbrellas over their heads.
Once upon a time knowledge was the prerogative of kings and priests and ruling castes; but this supreme power has been wrested from them, and this is the greatest step in human progress so far taken. "Seek and ye shall find," is the law concerning knowledge today. "Knock, and it shall be opened unto you." In this, my Book of the Mind, I say to you that knowledge is your priceless birthright, and that you should repudiate all men and all institutions and all creeds and all formulas which seek to keep this heritage from you. Beware of men who bid you believe something because it is told you, or because your fathers believed it, or because it is written in some ancient book, or embodied in some ancient ceremonial. Break the chains of these venerable spells; and at the same time beware of the modern spells which have been contrived to replace them! Beware of party cries and shibboleths, the idols of the forum, as Plato called them, the prejudices which are set as snares for your feet. Beware of cant—that ............