« PreviousContinue »
does, and when he has thus acquired data and facts enough he may construct upon them a theory that shall
fit the facts, but not before. The search A well-known line of a Roman poet expresses the desire for causes, of mankind to know the causes of things, "Felix qui potuit
rerum cognoscere causas.” You naturally wish to know causes; but it may be that nature will not reveal causes to you at all—but only facts. I take up something in
I my hand. What happens when I take it up? One set of muscles contracts and allows my fingers to stretch and to open ; another set of muscles contracts as I grasp the object. Why do these muscles contract? Because they were affected by nerves. How came the nerves to convey the impulse? The impulse was given from the brain with which the nerve is connected. How did this impulse originate? In a wish that I formed. Do all the
I motions of the body originate in acts of consciousness or in acts of will? No, for some muscles, those of the heart, and digestive apparatus, for example, alternately expand and contract with great regularity without any volition of ours, indeed we could not by an act of will keep up these motions if they stopped, or stop them when they were going on. Are these automatic motions then produced by nervous impulse? Yes. But whence then does the impulse originate? Not in this case from the brain, but from other nervous centres or ganglia situated in the spinal cord: Is it then so, that movements which are conscious, and are produced or controlled by the will, come from nerves which communicate with the brain, and that automatic and unconscious muscular movements originate in other and inferior centres of nervous action? Yes. Observe in all this, I have been seeking to know the
But I am no nearer knowing the cause at the end
me as ever.
than at the beginning. Why and how a thought or wish of mine which seems wholly spiritual and mental should produce the physical result of setting a particular nerve in tremulous motion, and why that motion should in turn cause a muscle to contract, is as great a mystery to
The only answers to my questions have been statements of fact. It is so. Such a circumstance is always followed by such another circumstance. There is the antecedent and its uniform consequent. That is all. Of the hidden nexus, or necessity which should cause the particular antecedent to be followed by the particular consequent, I know nothing.
Take another example. I let this pen drop out of and for my hand. Why does it fall? Because I did not prevent it. But why should it move in that particular direction, when I gave it no impulse but merely ceased to hold it? Because all objects when disengaged tend to fall to the earth. But why should bodies fall towards the earth ? Because the earth is a very large mass of matter, and smaller bodies are always attracted to large ones. But why and how do large bodies become thus attractive? Well, it is observed that throughout nature all masses of matter exercise mutual attraction and that the extent of this attraction is determined partly by their mass or density, and partly by their distances from each other. Is this true of the planets, and of the Sun? Yes. There is one broad statement which Kepler formulated in reference to this great fact of gravitation. It may be expressed thus, Gravity=Mass - The Distance squared, and is often called the law of gravitation.
Now you will notice here again that at each step Not causes I have asked the question Why? and that at no step have nor reasons
but facts. I received an answer. The answer I have obtained in each case is the statement of a fact only; but then each
fact was one broader, more comprehensive and general, than that which preceded it. The first fact was single; it was within the range of a little child's experience—that the pen fell. The last statement of fact, the great truth of gravitation, was far-reaching, sublime, co-extensive with the whole range of the universe so far as man can know anything about it all—a statement of fact which includes in its generalization the explanation—so we call it-of the movements of the atmosphere, of the rising and falling of the tides, and of the march of the planets on their heavenly way. But as a matter of fact, nothing has been explained or accounted for, no mystery has been solved. Each single fact derived from observation has been referred to some larger fact derived from wider observation, and the mind has been led to correlate a number of separate and diverse experiences under one comprehensive statement, to detect unity where there was apparent diversity; to substitute a great generalization for a little
one, a great mystery for a little one. That is all. Large And surely that is much. Is it not a large part of instead of
the education of all of us to be enabled to lift up the little ones. thoughts from what is petty and transient and exceptional
and to recognize in its stead what is vast, and typical, permanent and universal ? Truly we are the richer for the perception of the larger truth, even though it is just as mysterious and inexplicable to us, as the smaller truth was to the little child. “In wonder,” says Coleridge, “all philosophy begins, and in wonder it ends." The infant looks up into the sky with awe and bewilderment. The wisest man, when he knows all about the stars and their sizes and their distances and their chemical constituents, is fain to say, “When I consider Thy heavens the work of Thy fingers, the moon and the stars which Thou hast ordained, what is man that Thou art mindful
of him and the son of man that Thou so regardest him”?
It is also to be observed that the ultimate object to What are be attained in the pursuit of physical science is the per
Nature? ception of what is called a law. We speak of the Law of gravitation or of the correlation of forces. But the word Law is here used in a very special sense. In the sphere of morals and religion, it implies prescription and authority on the one side, obedience and obligation on the other. But in physics the word is simply used to describe some statement of ascertained fact, some general truth derived from observation. It is not a law in any other sense. We may talk loosely and popularly of obeying the laws of nature. But what we mean is simply this —that there are the observed facts; that experience leads us to conclude that what has proved to be uniform within the range of our experience, will continue to be uniform under the same conditions; and that in planning our own actions, in inventing, contriving, and adapting the forces of nature for our own purposes, we must take these facts for granted, and not expect them to be modified to suit
And if this be a correct description of the way in Processes
, which truth relating to natural and experimental science
required is attained; we cannot fail to see how important is the in physical
studies. mental discipline through which the student must pass in arriving at such truth. He must begin by noticing the phænomena, must put together and register the results of his observation ; must hesitate to generalize too soon, must suspend his judgment, until he has facts enough, must verify each hypothesis by new experiments; must learn how to make a legitimate generalization from a multitude of particulars; must hold his generalized truth, even when he has it, only provisionally, knowing that it
too may possibly require to be corrected, or at least absorbed by some larger generalization. And even when he recognizes a grand and apparently universal law such as that of gravitation he must leave room in a corner of his mind for the possibility of the existence of systems and regions “somewhere out of human view” to which the
law of gravitation haply does not extend. These And do you not see that the processes of mind thus processes available
brought into action, are very nearly akin to those by in all the which we are every day forming our judgments about intercourse
men and women, about political events, about the right of life.
and wrong of human actions? When we go wrong on these points it is more often through hasty and unauthorized inductions than from any other cause.
"I do not like foreigners," says one; “I have been in some parts of the Continent where the people were very brutal and dirty." "I do not think University examinations any
” true test of power," says another. “I knew a man who had taken high honours and he turned out a complete failure.” “Macaulay was very inaccurate, look at the mistakes he made about Penn." Do we not see in cases like this, illustrations of what Bacon was wont to call the inductio per enumerationem simplicem, the generalization too wide and sweeping for the facts; the inability to discern the difference between the act or event which is exceptional and that which is typical? Do we not feel, that what are wanted here are temper, reserve, breadth of mind, observation wide enough to comprehend a great many special details before arriving at large general assertions? And these are precisely the qualities of mind which the study of physical science generates and encourages. They are not brought into special activity either by the study of language or by the study of mathe. matics, valuable as both of them are in their place. For