Movements of Thought in the Nineteenth Century
Chapter 13 Modern Science is Research Science
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IT IS, of course, the research attitude which distinguishes our modern science. It has flourished more intensively in the last century and a half than ever before. There is one phase of it that I wish particularly to point out in this connection. Research science approaches certain problems. It does not undertake to give a systematic account of the world as a whole in any specific field. In the earlier period the function of science seemed to be that of presenting a systematic account of the universe, including all living forms; and great interest was centered in the mere statement of classes, families, genera, and species. Interest centered in the picking-out of the proper types, the selection of those characteristics which were best adapted for classification. But the interest in science shifted from that over to research work. Here we are thinking of biological science in particular. This is, however, true of all modern science. The research scientist starts from a specific problem that he finds as an exception to what has been regarded as a law. Given such an exception, he undertakes to present a hypothesis which will lead to the solution of the problem. His work, then, starts with the problem and ends with its solution. Now, what is involved in the solution is that the exception itself shall be accounted for, that a new statement shall be given which will overcome the opposition which the problem suggests.
The illustration of this process that I have often used is that of the sporadic appearance of a contagious disease. Before we knew about the microorganisms that carried the disease, it was assumed that the disease was carried by actual contact. A sporadic case is an exception to the rule. Where no person has the disease there can be no contact. The sporadic case, then,
(265) is an exception. Now, the scientist starts off with a given point of view, a given theory, a given technique; he finds an exception to this; then he sets about forming a hypothesis which, on the basis of facts which he gathers together, will enable him to connect this exception with the other facts which are recognized and which can be established. Such a hypothesis was that of a microorganism which can bring disease, which itself is carried by a stream of water or in milk, or in some such fashion. This is a satisfactory illustration of the research method. It starts from an exception and undertakes to fashion a hypothesis which will bring these conflicting causes into relationship with each other.
The research scientist does not guarantee the conceptions with which he starts. He has worked on the theory that an infectious disease of some sort goes from one person to another. The common theory had been that there must be actual contact between the man who has the disease and the person who catches it. The scientist accepts this theory for the time being, but only as a postulate. He does not accept it as something to be taken in a dogmatic fashion. He accepts the clinical account of the disease, the history of it, the way in which it presents itself-accepts it from the point of view of the science of the time but not in a dogmatic fashion. He is perfectly ready to find problems in all phases of his theory. In fact, the research scientist is looking for problems, and he feels happiest when he finds new ones. He does not cherish laws and the form in which they are given as something which must be maintained, something that must not be touched. On the contrary, he is anxious to find some exception to the statement of laws which has been given.
Science starts with certain postulates, but does not assume that they are not to be touched. There is no phase of the world as we know it in which a problem may not arise, and the scientist is anxious to find such a problem. He is interested not merely in giving a systematic view of the world from a science already established but in working out problems that arise. This
(266) is the attitude of research science. What I particularly want to point out is that the assumptions which lie behind this science are only postulates. We assume, indeed, that the world is ordered in accordance with law, that processes in it are uniform. Otherwise, of course, the world would not be knowable, at least not in the sense in which science knows it. We know the world in terms of laws, but we do not assume any certain laws to be the final formulation. We expect these laws to be continually changed. We would think any science barren which did not in one generation give a different view than that held by the generation before. And, if that difference is a fundamental one, we think science just that much more productive.
The distinction between the scientific postulate and the dogma is the distinction between research science and the science of Aristotle. Aristotle stated that it was the nature of a heavy body to tend toward the center of the earth. He set that up as a dogma, as his particular definition of a heavy body. From that he could deduce any logical conclusion-for example, that the heavier the body the greater the tendency toward the center of the earth. If that is the case, then the velocity of the falling body must be proportionate to its weight. There you have a solution of a problem in a dogmatic fashion, deduce from a dogma.
The scientific method is aptly illustrated by the procedure of Galileo. Questioning in his mind, from instances he had seen, whether or not this conclusion of Aristotle was true he took bodies of different weights to the top of the leaning tower of Pisa, dropped them, and found that their rate of fall was not in proportion to their weight. Then he set up apparatus to discover whether or not he could find a law in accordance with which they did fall. He did not start off from a given theory which stated what the nature of the falling body was and then undertake to deduce from that what its velocity must be. Rather, he undertook to find out just what the velocity was, to see if it agreed with this law or not; and, when it did not, he set up a hypothesis that the velocities of falling bodies vary with
(267) the time of their fall. With as accurate an apparatus as he could produce, he found that his results accorded with that hypothesis. It became, then, a theory, if you like, to take the place of the older Aristotelian dogma.
From the point of view of the scientist, Galileo's theory is a postulate. He does not set it up as a statement of the nature of the body, as Aristotle did. Galileo set it up as his postulate because it agreed with the facts. If, however, later observations should show that it did not agree, then any scientist would be only too glad to change the doctrine. All universals used by scientists are postulates of this sort which are accepted as long as they are in agreement with the facts. When they differ from the facts of observation, they have to be reconstructed. We can say, then, that science deals with hypothetical universals. Its conclusions are hypothetical propositions. If such and such a law holds, such and such a result must follow. But scientific research does not attempt to establish the law as something absolutely given.
Of course, the old medieval attitude had been that of a giveis form or statement of causation, a science inherited from Arntotle (sic). And when Galileo suggested that bodies fall with velocities not in proportion to their weight, he was regarded as a heretic. From this you can see that the change in attitude which research science involved was very profound. While it starts off with certain assumptions, these are regarded only as postulates, and nothing more. They have no inherent virtue, no inherent authority.
One of the basic postulates of the scientific view which I have been presenting was the mechanical character of the universe, the assumption that we can, for example, state the whole life-process in mechanical terms. Such an assumption is a postulate which the scientist makes, but it is only that in his eyes. He is entirely justified in using it in that capacity until he can hold to it no longer. The conflict, so far as there is one, is between a mechanical and a teleological view of the world. This conflict has become peculiarly acute in biology.
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If you are dealing with the force of a stream of water, you look at it from a mechanical point of view-so much energy at this point, the water falls so far, and so much energy is developed below. That is an account which is a posteriori, from behind. However, if you undertake to deal with such phenomena as the digestion and the assimilation of food, you start off with the assumption of a certain function to be carried out. This function is what would be called, in terms of an Aristotelian science, a "final cause." All this apparatus is there to accomplish a certain purpose. If food is taken in, it must be digested before it can be assimilated. The apparatus is there, then, for this function. We set up the end as something which is there to be carried out in order that a certain result may be reached. In biology we proceed with mechanical causes, but we have to have final causes in our interpretation of these. If we try to go into the actual digestive process, we have to have recourse to the chemical laboratory. We assume that the sort of organism in question has to perform a certain function; but when we come to state the operation of this function, we do not state it in terms of final causes, but in mechanical terms. We want to show that, if we have certain chemical substances present in certain combinations and we add other substances, a certain change must occur which will lead to such and such a result. That is, you explain the process from behind. You do not say, "This must be digested, therefore it must be changed in such and such a way." You say that this food is brought into contact with certain substances and that therefore it must change. You get an explanation that lies behind instead of in front. That is, you have a mechanical, instead of a teleological, explanation.
Another illustration of the difference between a teleological and a mechanical explanation is found when you set about to account for a certain murder and you say that the man who had an interest in the death of the murdered man was the cause of it. It is the end which the man had in view. That is the explanation of what takes place. If, however, the physician who is
(269) called to account for the murder does so, he says a bullet entered the body in a certain way and led to a given result. There you get the mechanical statement, a statement in terms of cause and effect. This effect is caused by another effect, and so on. You have a set of causes and effects which follow one another. If, on the other hand, you are interested in the case as district attorney, you look to ends, rather than to causes and effects-ends which the murderer had in view. The latter wanted the person's life insurance or his property. That end, the attorney says, explains the murder. That is, he gives a teleological explanation, while the doctor who performs the autopsy gives a mechanical explanation.
In biological science you bring in both these points of view. We say that, in order for the plant or animal to live, it must digest food that it takes in. This is an end that it must accomplish. Then you try to show how this takes place; and to do so, you make use of a mechanical explanation. Well, the two points that I brought out, that of the possible statement of life-processes in mechanical terms and an account of the origins of species, seem to take away the necessity of a teleological explanation. If you could make a complete statement in mechanical terms, you would not need to bring in the teleological explanation at all. If you can show just what the position of all the physical particles is, what changes they must go through, what motions will take place, what reconstructions will occur, you finally get a statement which you can understand, and one which does not involve ends. The teleological statement, on the other hand, in a certain sense, sets up your problem for you. The animal has to digest his food. How does he do it? The manner is stated in mechanical terms, but the problem is teleological. Now, supposing you could carry out the whole process of living in mechanical terms, you would not have to bring in a teleological statement at all.
That is the basis of the objections which have been offered to the so-called "mechanical sciences"; they take the meaning Out of life, take out its end or purpose. And this objection, of
(270) course, was made all the more vivid in the contention over the idea of evolution. Here, seemingly, you have a mechanical explanation for the appearance of species and of their different organs. All you ask for is a set of indefinite variations, a competition for existences, a changing environment. All these can be explained mechanically. Presumably, you can show, or at least Darwin assumed that you can show, that every form must vary in some way from its present form, and also that variations could be handed on to the next generation. Of course, this assumption has been questioned. But it is the assumption which Darwin's doctrine carried with it. It was necessary to recognize the fact which every biologist did recognize, namely, that more young forms are born than can possibly live. Consequently, there must be a resultant competition for existence. You have to recognize this competition that biology, together with geology, points out, namely, that the environment is constantly changing, so that the adaptation of a form to one environment does not adjust it to another. There you can explain the origin of new forms by means of causes which lie behind. You do not have to say that there is a creator having an idea of a form and then fashioning it after that idea of his in order to carry out some purpose which he has in mind. You can simply show that causes operating in a certain way will lead to the appearance of new forms, and so you can explain the latter mechanically.
It was that which led to the very vivid fight over evolution, a fight which still continues in some parts of the world. Now, what I am emphasizing is that such an appeal to a mechanical explanation is a postulate that science makes. Its fundamental postulate is that the world is knowable, and, if so, there must be a reason for everything, and this reason will have a universal form. Of course, science has to make that assumption, for it is its business to know. Therefore, it must postulate that things are knowable. And knowing is finding uniformities, finding rules, laws. But we do not assume that the laws we have discovered are the statements which persons are going to accept later. We expect to have these laws changed. Now, one of the
(270) assumptions that the biological sciences make is that they can give a mechanical explanation to what goes on in the life-process. Perhaps they may be mistaken about this. If they are, they will be just as ready to recognize that as they are to recognize any other exception. But it is a natural and a perfectly legitimate postulate. We must go on assuming that we can give physical and mechanical statements for everything that takes place inside of us until we cannot accept these statements any longer. We must make that postulate, but we must make it a postulate and not set it up as a dogma. As long as we accept such a statement as a postulate, we are entirely justified in it. For it has been supported by the successes, the achievements, of science. It opens a door to the understanding of the world.
There is, then, no real conflict between a mechanical and a teleological account of the world or of the facts of life. The scientist who approaches the problem of digestion inevitably undertakes to make a chemical statement of what goes on. He still takes the attitude that starches are digested so that the life of the form may be maintained. That is, he states the process in teleological terms. Of course, if he carries evolutionary theory still further, he can say that this so-called purpose is nothing but a mechanical process of the survival of one form over another. But the particular form in which his problem arises is teleological. How does the digestive process go on that does enable life to continue? Take the question of the secretion of the various glands of the body. What we assume is that the various processes that are taking place there have to result in a nice adaptation to the conditions of the life-process, and that the stimulation that comes particularly from the ductless glands is essential to carry this out. We see that certain of the secretions, such as that coming from the pancreas, enable the blood to carry more sugar and to carry it in a form in which it can be Most readily turned into energy. The animal must expend energy rapidly. The sugar in the blood enables him to do that most readily. But in order for it to be there, for it to be available, the system has to be tolerant of sugar. Therefore you have
(272) to have the pancreatic secretion. You see, you set the process up in teleological terms and then explain it by finding actual chemical processes that take place. You get a statement which starts off in teleological form, and then you give a mechanical account of it.
Science does not feel any conflict in such a statement. The scientist is perfectly willing to accept the problem, and he looks forward to as complete a mechanical statement of it as is possible. And he is perfectly justified in setting up this point of view until it breaks down. He can say that, theoretically at least, a mechanical statement can be made of the whole world. But he does not necessarily assume that that will be an adequate statement. The complete mechanical statement would not take account of the end, of the purpose, to which we have referred. And that seems to be necessary to our comprehension of the world. Yet there is no conflict between that teleological statement of it, on the one hand, and the mechanical, on the other. Science does not feel any conflict there. Therefore it has welcomed every advance in mechanical science because it enables it to give a statement, an explanation, of that which is taking place. The more complete you can make your mechanical statement, the more satisfactory you can make your explanation. You must postulate that such a mechanical statement of the universe can be made. And then, if you find that it is not satisfactory, you can throw it over. But you must make an assumption that such a mechanical statement can be made.
That is the attitude of our modern science. If science were dogmatic, that is, of the Aristotelian type, then to postulate a mechanical account of things would mean to abandon definitely all final causes, all ends. We would have to set up a theory, a philosophy, a theology, ,Nhich would be of a mechanical sort. That is the difference between the mechanical statement that is suggested in the ancient world of Democritus and that of research science of the present time. The scientist's use of the mechanical explanation does not carry any dogma with it. He is entirely justified in making a postulate that he can give such
(273) a statement without being involved in assuming that there is no meaning in the world beyond this mechanical statement of it. His attitude does not carry that assumption. It leaves the whole question open. All the scientist assumes is that he can make such a mechanical statement, and he gives evidence to show that he can carry it out. The result is that research science has been able to take over a mechanical theory of the world and postulate such a theory without committing itself to any philosophy based upon it.
You can find scientists who do admit such a mechanical philosophy. In the middle of the seventeenth century a perfectly definite materialism undertook to abandon everything except the mechanical view of the world, not in terms of a postulate, but in terms of a dogma. It assumed that consciousness, socalled, was nothing but a secretion, in some sense, of the brain, just as bile is a secretion of the liver, and that you could treat it as any other physiological process. It assumed that there was no end or purpose in the world, nothing but mechanical procedure. What I am distinguishing between is the postulate on the part of the scientist that he can find some statement, some explanation, some solution, of his problem and such a dogma as this that there is nothing but a mechanics of physical particles in the universe. One does not imply the other. And our science is free because it is able to make use of such a postulate without being committed to it as a dogma. What people found was that such a statement of materialistic science, when taken to be the end, did not mean anything. But, of Course, it exercised a very considerable influence as late as the middle of the nineteenth century. Darwin seemed to make such a dogma all the more practicable and plausible, and you find certain so-called "evolutionists" taking such a view of the universe. For a time the question of evolution seemed to be the question as to whether, as Disraeli said, you were on the side of the monkeys or that of the angels. As for him, he was on the side of the angels! That is a silly way of presenting the situation. If you get a mechanical statement which will account for
(274) the origin of species, so much the better. The mechanical statement is a postulate you set up, and you must carry it out just as far as you can, up to the point where it breaks down. And nobody is happier than the scientist if it breaks down, for then he will have another problem. He can make a postulate without setting up a dogma. And a postulate of the mechanical account of the world is that which science sets up, but not a dogma that answers to that. In science itself, there is no attempt to set up a materialistic philosophy.
The development of science, then, during the last century, the carrying-over of the statements of physics and chemistry to everything that is going on, gave tremendous push to our understanding of the world. It also had this definite effect, to show that science could tolerate no dogmatic statement. Science does not attempt to set up a dogma, as I have already insisted; and, of course, science cannot tolerate any other person's setting up a dogma. If your theological account becomes a dogmatic account, then science cannot accept it. If you say that the world was created in six days, and that creation started at some period between four and five thousand years before Christ, as stated in Bishop Ussher's calculations, you set up dogmatic statements with which science is in inevitable conflict. Science will at once turn about and ask for a justification of Bishop Ussher's calculations, will look up documents, ask what they are, where they came from, who wrote them, and pull the dogma all to pieces. If you set up a dogma of that sort, science inevitably undertakes to find a problem in it.
The field of biblical dates is, of course, one in which we find one of the most striking applications of scientific method during the nineteenth century. It passes under the name of "higher criticism." In the form in which it appeared, it started not with the Bible but with Homer. There had been more or less discussion of the Homeric texts way back in Alexandrian days. The German schools set themselves to work on these texts and found all sorts of problems. The solution which one clever Oxford fellow gave was that the Iliad and the Odyssey were written
(275) not by Homer but by another man of the same name! But what they were at work upon was to disprove the theory that these texts were written by any one man. They showed how the works had arisen and how they became woven into the form in which we have them at the present time. And that same sort of interest was turned loose on the books of the Bible; and these fell to pieces in exactly the same way, and the authors ascribed to them were shown, many of them, to have been mythical. So the dogmatic structure of the church, its theological structure, inevitably came into conflict with science.
Thus we see that science has gotten away from metaphysical dogma as to what the nature of things is, and goes back to the ordering of events which it observes. It states its laws in terms of uniformities, but it is always ready to change any statement it has made.
The acceptance of the scientific method is the most important phase of the intellectual and spiritual life of the Renaissance. I have been indicating what follows from that acceptance of the scientific method, the method of research science. It is not possible to set up any fixed statements of the laws of nature which must hold under all conditions. All that can be said is that up to the present time we have observed such and such uniformities. We postulate that those uniformities will continue. If they do not, then we will restate the laws. Of course, a still wider generalization, namely, that there are uniformities in nature, lies back of this. In the form in which science uses this postulate it seems to have come into the Western mind by way of religious doctrine. The fundamental belief had been that the world was created by an infinitely wise and omnipotent being who must have worked in an intelligent and intelligible fashion so that everything could be explained if one were only able to get back to the fundamental situation. There was a reason for everything. That is not, for example, the assumption of an Aristotelian science, which admitted certain accidents in nature that could never be explained. There were uniformities, but there were also exceptions which were just there as brute
(276) facts. The fundamental assumption that the world is explicable is also an assumption that the world is intelligible, that is, that we can know it. Knowledge is never a mere contact of our organisms with other objects. It always takes on a universal character. If we know a thing, explain it, we always put it into a texture of uniformities. There must be some reason for it, some law expressed in it. That is the fundamental assumption of science.
The scientific statement of causation is an excellent illustration of this uniformity. Science, in its more dogmatic phase, set up a universal law of cause and effect. Every effect must have a cause; every cause, a like effect. The scientist found, however, that an attempt to define causes was most difficult - finally impossible, in the sense in which these terms had been used. What could one consider to be the cause of any particular event? Let us take again the illustration which I used before, that of the assassin killing his victim. What is the cause of the latter's death? From the point of view of the prosecuting attorney, it would be the action of the assassin himself. From the point of view of the social psychologist, it would be the influences which had led to the murderer's taking such a step as that. From the point of view of the physician, it would be the actual entrance of the bullet into the victim's body, or the breaking of a blood vessel. There are different causes; and when you attempt to define causation as such, you are in great difficulties. What science has done has been to substitute for the idea of cause as a force simply a uniformity which has been discovered in nature and which we may expect to continue. What we come back to, then, is a theory of probabilities. The different causes to which I have referred in this particular illustration are causes that are determined by different interests, The prosecuting attorney has one interest, that of convicting the guilty person. The social psychologist has an interest in determining the conditions out of which such a crime arises. The physician has still another interest in determining just what the situation within the body of the victim is, what particular vital spot has been
(277) reached by the bullet. You have sets of different interests, and each interested person selects one phase or another of the situation and labels that the cause. What lies back of all these different views is a set of uniformities: those which led, for example, to the officer's detecting and arresting the criminal; those which led the social psychologist to form his judgment as to the effect of social conditions on persons; those which led the physician to identify certain conditions of the tissues with certain results. What the cause is in each case depends upon the selection of some particular one of those conditions which is of interest to the particular individual. And we call these the "causes of the event." Generally, it is some condition which can be changed in order to bring out a different result; but you can see that, as the interests vary, the causation, in our ordinary use of the term, will vary. Well, science in its general statements is not interested in these changes which are to be brought about, but it is interested in giving the uniformities which lie back of what we term the cause, so that the so-called laws of nature are the uniformities of nature. Any particular cause is some one element, some one fact, some one event, in such a uniform series. We expect that, if that or a like event occurs, the corresponding event will follow upon it; and we fall back upon our judgment of probabilities for justifying us in that judgment.
But even that assumption of uniformity is a postulate. Science has no absolute evidence that the world is explicable. It has only discovered a minute number of the so-called laws of nature. And yet, we go on the assumption that the whole of nature is intelligible. It is a postulate upon which we act and upon which science will undoubtedly continue to act, but no absolute proof can ever be presented for it, Not even an inductive proof can be given of it. It is impossible to say that, because we have found so many instances in which the operation of nature is uniform, therefore it is probable that the whole of nature is uniform. You cannot set that up, for you are assuming the uniformity to start with. That is your major premise.
(278) You can never prove that nature is uniform by means of an inductive syllogism. But nonetheless, science sets up this postulate and will continue to set it up. Not to accept it would be to surrender the results and undertakings of science, at least in certain fields. The fact that science may not be successful in certain fields does not disprove those postulates. No one can ever really disprove this postulate of the uniformities of nature, because it may be that we have not gone far enough. We could always still recognize the possibility that there might be a reason which we had not found yet. Science in its attempt to know will always carry with it the assumption that the world is knowable. However-and I must insist on this point-it remains only a postulate, inevitable, if you like, but one for which no absolute proof can be offered.
One of the results of the freedom which this gives science is the introduction of new concepts, concepts which are recommended because of their usefulness. I have already pointed out to you the important part the steam engine played not simply in the development of industrial production but also in the development of physical theory. The theory of the steam engine was first successfully attacked by Carnot, who, you remember, conceived of the steam engine as doing work in a manner analogous to that of the water wheel. It does work because the heat may be conceived as running down from higher to lower levels. As heat "runs down hill," it performs work just as water does as it runs to lower levels. After heat has reached the lowest level, it can do no more work. Having got down below the level at which it can expand, its ability to perform work ceases. You see here that the development of this theory was introducing a new scientific conception, new at least in the form in which it was presented -- a concept of work done. Carnot, bringing together the process of the water wheel and the steam engine, set up this conception of the amount of work done as that which could be used for computing these two methods of operation. Of course, a unit had to be worked out, and the foot-pound was proposed. This idea is of the amount of work done in raising a
(279) pound weight through a distance of one foot. You could do that by means of the water wheel or by means of the steam engine. Then, answering to that unit, Carnot set up the idea of energy. Here is a certain amount of work done-done, of course, in very different ways in the two mechanisms-but a common result is achieved. As a means of computing the results of these two operations, Carnot, and those who carried out his theory, set up this conception of a unit of the amount of work done, and then they set up a supposititious energy that answers to this. There must be a certain amount of energy responsible for doing this amount of work, no matter what the type of mechanism used. It is a very interesting illustration of the introduction of a new concept answering to a new scientific situation.
Of course, back of this new concept lay the ideas of force. If you go back to Newton's mechanics and ask what a force is, you are told that it is a cause of motion. If you try to state that cause, you have to state it in terms of other motions; and a force remains outside the field of your actual observations. Of course, you can observe all the various motions. But energy, you see, is something that is set up answering not simply to a motion but to this conception of work done. This conception was really introduced in an effort to work out a theory of the steam engine. And one of the most important phases of the doctrine lies in this very conception out of which the situation arose, that of bringing together the water wheel and the steam engine as accomplishing the same thing, as having, therefore, the same energy, that is, as responsible for the same amount of work done. You think, then, of a steam engine as developing a certain amount of energy, of the water wheel as developing a certain amount of energy, the amount of energy being the same in both cases. Energy is simply something stated in terms of what it brings out, a certain amount of work. It is, then, something that can be located in one situation and in another; and it cannot only be located but it can be transferred from one to another and another and another situation. Suppose you
(280) want to produce electric light. You take the energy that is found in coal and transfer it to the revolution of your dynamo, thus changing it into the energy of an electric current, and so finally into the glowing filament. Thus, you have carried your energy from one form to another. Having set up this unit of work, having defined it in terms of energy, you can now go back and discover the energy that is responsible for a given amount of work now in this form, now in that, now in another. It is a very good illustration of the way in which scientific concepts arise. It is not simply the idea of a cause of motion which really has to be pushed outside of the doctrine of physical theory; it is a conception of something that can be regarded as responsible for a particular sort of result, that is, of a particular sort of work that is done. And then, when you have set up this relationship, wherever you can get that amount of work done, you can say you have just so much energy.
From this conception of energy which could be transformed and found now in this form and now in that arose that great generalization of the nineteenth century, the conservation of energy-that there is always just so much energy only it takes different forms. If you can find this energy now in one form, now in another, then all that has happened is that it has been transformed. In a sense this law of the conservation of energy was proved. If you make this postulate, you can show in any particular system which you set up that the same amount of energy is present throughout the whole process. That is, a number of instances are given of a certain system in operation, and it can be shown that the amount of energy in that system is constant no matter what different forms it may take. I want to point out this instance and put it in your minds along with the other great generalization of the century -- the hypothesis of evolution.
What I have been saying about the scientific method applies also to the social situation, and makes it possible for the whole community to grasp the ends of the community as a whole and to make those ends the interest of the individual. That is con-
(281) -ceivable and, as we shall see later, is the basis not only of social relations but of the appearance of selves. This community of ends is often achieved. For example, in the matter of hygiene, let the whole attention of the trained staff of the community be turned toward the care of the health of the individual and you reach the health of the community. And you can only reach the health of the individual adequately by reaching the health of the whole community. Save the individual, and you cherish the good of the community. And you can accomplish the latter only by saving the individual. This is the ideal of Christianity, only in this case it must be the salvation not of the soul but of the body.
The result of such a movement as that which we are considering is to get away from the abstractions which are involved in this separation of soul and body, of mind and body, of the spiritual and the physical. It is a phase of the influence of the scientific method that I want to emphasize as over against the seeming mechanical character of science. On the face of it, as I say, it presents absolute necessity, a law which determines where every physical particle should be at any moment throughout the whole history of the universe. While this seems to be a prison house for any intelligent effort, what it actually serves to do is to present the apparatus for the control over the environment and for bringing larger and larger ends and ideals within the vision of humanity. It is that side of it I wish to bring out before I leave this seemingly mechanical science.
I now want to turn briefly to a discussion of the general philosophical effect of this development of science. What I was emphasizing was the scientific method and its import. In the first place, that brought men back to observation. You remember that the scientific problem is one that arises out of the exceptional event, something that is contrary to laws as they have been accepted, so that attention is directed toward observation and toward a statement of the so-called "fact" in terms of the problem that arises. It is well to recognize that observation is not simply an opening of one's eyes and seeing what
(282) there is about, or opening one's ears and listening to what may occur. It is always directed by some sort of a problem which lies back in one's mind; it always expresses an interest of some sort. We are looking for something that is relatively novel. What we are trying to find are facts which are of the same sort as those which have been noted. Now these facts always represent possible or implicit problems with which science deals. We speak of them as "hard facts," because they have been hard enough to break down some law, some accepted idea.
For example, take the situation underlying the problem of perception. You recognize an acquaintance on the street, start to speak to him, and then find he is not the right man, after which you know there are differences that you did not note at first. Now those differences represent the problem to you, the problem of why you should have mistaken this man for your friend. They are hard facts, they defeat the anticipated conversation which you are going to have. They defeat the meeting with the friend. You have run up against an obstacle. When you recognize an acquaintance, you pay no more attention to the actual features than is necessary for the recognition of the person, that is, for allowing your conversation to go on. There is no purpose in giving attention to more than that. You just want enough to assure yourself that he is the person you think he is. But, when you have started to speak to him and find he is somebody else, then the differences stand out and you remember how your friend really looks, and you wonder why you should have made such a mistake. Or you recognize certain likenesses.
That is the character of the so-called "hard fact." And the scientist is continually noting that which departs from the accepted view, the given laws. With him it is not a disappointment but an achievement, a new problem to work on. He approaches it with interest and excitement. It is a discovery of something that is an exception to the view that has been held; it is the getting of something novel. These facts, then, arouse
(283) interest and observation. And they not only do that, but they lead to the formation of a technique of observation. I have said that scientific observation is not simply the opening of one's eyes and seeing things as the images happen to fall on the retina. What it is, is the recognition of the relationship of those things which you see to the customary view. And you have to examine facts from that standpoint. That is, you have to state them in the form of a definite problem. In the case I have just given from perception, you note that which makes you certain the person you meet is not your friend. You have to make that definite and clear. It might be an acquaintance who had had a long illness, so that you hardly recognize him. You have to assure yourself whether it is or is not the friend. You bring the images, the facts, into relationship with your customary intercourse. And then you may go to see what the likenesses were that led you to make the mistake. Now, when you come to the scientific situation, you have the so-called facts before you in terms of their exceptional characters. And you have very carefully to define in what that exceptional character consists.
The illustration of the sporadic case of the infectious disease, to which I have referred, shows this. You have believed, up to the appearance of this problem, that disease was conveyed by contact with someone who had it. Now you have a case in which there is no contact. Your observation forces you, under these circumstances, to make absolutely certain that there was no such contact. You have to comb the neighborhood. You have to make sure that the person who has now come down with the disease was not a stranger who brought it from elsewhere. You have to determine very accurately that this is an exception to the law. You have to state the case in terms of the law and show that it is an exception to it. And then, when you have that stated, the first thing you do is to look around for other instances. Now you have a way of defining your facts in terms of this law, and you look for other sporadic cases and put these down. This means that as a part of scientific method you must observe that which runs counter to the currently accepted laws.
(284) To do this you give a very careful definition of the exceptional instances in terms of the law, so that your observation is of certain particular characters. And given these, you are able to gather all other similar instances. This enables you not only to state your problem exactly but also to insert, so to speak, the negative form of your hypothesis. It states your problem for you: How does this sporadic case, or rather these cases, mapped before me, arise in a district in which there were no other instances of the disease? The reason for it, presumably, will have something to do with the distribution of the cases, for these persons have contracted the disease in some unknown manner. There must be a common cause. You have no hypothesis, as yet, as to what the cause is; but it must be a cause which can operate in this series of instances. Therefore, you must have a hypothesis which fits in with the facts.
This is what the scientific method of observation consists in: it is the observing of that which runs counter to accepted opinion, current laws; it is the statement of the so-called facts in terms of their exceptional character; and then a gathering of all other facts that you can get hold of which are of the same sort and which will show you something of the nature of the hypothesis that may possibly meet that situation. You find that the cases of a disease are all located along a river. Then you can say that the infection is very likely one which has traveled along a water course. There you get the form of your hypothesis. If you can find some infective microorganism that can travel in water, you can test out your hypothesis. There is just as much accurate technique in observation as there is in experimentation. What experiment does is to take the hypothesis that you have formed and see if it will fit in with the facts which you have before you and other facts which you can gather. Your experiment is especially constructed so as to determine whether the hypothesis will agree with the facts. You assume that something is to be found in water. You actually isolate a microorganism; you try it on a dog to see if that particular microorganism will give rise to that particular disease
(285) in the dog. Then, having got that into the dog, you recover the microorganism from the dog itself and try it on another dog. You examine those animals which have not the disease, and prove to your self-satisfaction that they have not the organisms in their systems. So you prove positively and negatively that, where the organism is present, the disease is present, and, where not, the disease is not. But your original observation has to be as accurate as possible. You must define your facts in terms of the accepted law in order to see in what way they are exceptional. That is what we term the "scientific method."
What I was pointing out with reference to what is of particular importance from the general philosophical standpoint is that these laws which are overthrown by the facts are laws which had been accepted and have now disappeared as laws. You are undertaking to set up another law in place of the one which has been overthrown. The new law is tentatively set up as a hypothesis. You test it. When you have tested it, it becomes a working hypothesis. And if others test it and it works, it becomes an accepted theory. But, although it is an accepted theory, it is still subject to some other chance exception. That is, it still remains hypothetical. What I want to point out is that the necessary conclusions that science draws are always in the form of a hypothetical syllogism. You say this must be truescience has proved it. But if you get back to a statement by a good scientist, you will find that he is careful to say that, if these laws which have been tested by experience continue to hold, if no new exceptions appear, then such and such a result must follow. The necessity in this case is hypothetical. There are no laws of nature which are given in such a fashion that they can be made dogmas. That is, you cannot say that any law is absolute and fixed. The laws of nature, as used by science, are always hypothetical. If some exception appears, then they will have to be remade. That is the form in which all our so-called laws of nature exist in the minds of the most careful scientists. They are there as hypotheses; or, to use the expression I have used before, they are postulates. We postulate these
(286) laws; we reach certain results; we act on these results; we get the satisfaction we expected to; and we accomplish what we set out to accomplish. But new facts may arise which may make it necessary to reconstruct the postulates. We have always the private faith that any law may have to be reconstructed. Indeed, the law may disappear; but another law will be found to take its place. The law is dead; long live the law! There is always some possible reconstruction that can take the place of it. No statement that science makes is final.
We have had a striking illustration of this in the last few years in the appearance of the idea of evolution and in the modification of the fundamental laws of the Newtonian world. In both cases laws were found to be incorrectly or inadequately stated. They have had to be restated from the point of view of new experiences. We advance, then, by the use of postulates which have worked. And we continue to use them as long as they work. We can recognize that these postulates may have to be abandoned; but we also recognize that, if they are abandoned, we shall put up others in the place of them. That is the scientific method which came in and ousted the older technique, the dogmatic attitude toward the world.
There is one phase of this development to which I wish to return for a moment, that of the idea of energy. By means of it I wish to illustrate the different sources from-which science gets its exceptions, or perhaps I should say the different points at which problems arise. As we have seen, in this case the problem arose out of the steam engine, which had become a very important factor in the life of the time and which made it necessary to work out a mechanical theory of it so that it could be controlled. The steam engine worked by forces which people did not understand. but what they were ;.tire of was that there was a certain amount of accomplishment, of work done. They set up the idea of a something which was there, which could be found in coal, in the revolving wheels of the machine, in the electric current - a something there that answered to this work done. And they called it "energy." As I have said, they assumed on
(287) the analogy of the water wheel that the steam, as it flowed from higher to lower levels of temperature, did this work. Work was proportionate to the fall. The work which could be done was in some fashion proportionate to the amount of heat. So the laws of thermodynamics were worked out.
This led to the conception of entropy, the assumption that there exists throughout the whole of the universe a certain amount of energy which is in different degrees of excitement. Temperature was recognized as answering to the movement of things, of molecules, the sort of movement which we cannot see, which we cannot feel with our fingers, but which reveals itself to us in terms of temperature. Wherever there is energy, it is assumed that it is an instance of that sort of motion. Now, according to the laws of energy, this motion is all tending toward a uniform minimum in which it will be evenly distributed all through the physical universe. Where you have a great rate of motion, that motion will impart itself to the other molecules about it, and that to still other molecules, and gradually there will be an evening up. If there is more motion in one place than in another, there will tend to be a situation in which the amount of motion will be the same everywhere. Thus) temperature can be conceived of as streams of water which are all running down toward an entropic ocean, where the motion will be at the lowest degree but the same everywhere. The whole world seems to be running down toward that result.
While that conception still remains, it has lost a good deal of its interest. We are now approaching the scientific problem from another standpoint; and the conception of entropy, while still retained, has not the import that it had before. We are now stating our problems in terms of waves, not of heat. The question of entropy was one that arose out of the appearance of the machine. And, as we have seen, in a certain sense the machine dictated the conceptions which science itself should utilize. That is, industry wanted a unit that would answer to work done. Industry was interested in work. It divided its work up ,into single units, steps, such as the foot-pound . That became
(288) the accepted unit of work. Now look to nature, where we are seeking for forces to drive our machines, and see if you can find something to answer to this unit of work done. Society, as I said, came forward with a problem, that of controlling the forces of nature as they appeared in machines. These machines worked. If we can get a simple unit, this work can be expressed in any instance in which we find it. We will look in nature for forces which will do work, and we will state them in terms of units of force. It is, very interesting to see how society set up this problem for the scientist. The former had its job on hand-that of introducing machines-and it wanted a scientific statement of nature that it could utilize for that purpose. With its task of getting a certain amount of work done, it looked into nature for something that answered to that work; and this was supposed to be energy. There might be gradation of energy. This particular telephone here at my side represents a certain amount of gradational energy. If I let it drop, it will do a certain amount of work.
From all this you see that science becomes really quite fluid instead of being a fixed dogmatic structure of the world. It becomes a method, a way of understanding the world, so that we can act with reference to it. And the problems that arise are those involved in our conduct with reference to the world. That conduct has a great many phases. It is not simply the conduct involved in driving machines. It is also our conduct with reference to other members of society. Religion, for example, undertakes to interpret the meaning of the world. It calls for a certain type of conduct on the part of those who accept religion. Science may come in to determine whether the concepts which religion embodies are in accord with what we call the "facts." It then face,; another problem.
Such a situation arose, as we have seen, in the case of evolution. The accepted religious doctrine stated that all the different forms of plants and animals and physical things were given by fiat of the Creator. They were made just as they were by God, and they remained in the form that he gave them from
(289) the day of creation. Science examines the origin of species. It shows that there is no strong evidence that the forms of things arose in the creation of a day. God, of course, may have been responsible for their life; but he did not, if this statement of evolution is correct, create the forms as such at a particular moment. Well, science presented evidence to us that the forms themselves arose in the life-process, and then it came into conflict with the dogma of the church. And it was necessary that the dogma of the latter should be restated if man were going to continue to govern his conduct by science. Inevitably, in the end the dogma will have to be restated, because people are controlling their lives by science.
If you want to deal with disease and with the various technical problems presented to us-those of transportation, of communication with distant people-you must deal with them in a scientific manner. You cannot have two methods of conduct which are separated from one another. In the end your scientific conduct will be dominant, so far as dogma is concerned. It is not, you see, so much a question as to whether or not science can demonstrate a theory of the world. It is a question as to whether people are going to act in accordance with scientific technique.
I must insist again that scientific interpretation does not set up one dogma in place of another. What it sets up are postulates. It sets up hypotheses on the basis of which we act, and we will continue to act on them as long as these hypotheses work. They will be reconstructed when exceptions are found. Back of these postulates, however, lies the constant assumption that the world is intelligible. That is, if we abandon one hypothesis, we at once set about to build up another. From the Point of view of dogma, this procedure would be a confession of failure. It is like people continually building cities under volcanoes: they are repeatedly overthrown, only to be built up again. But science is not stating dogma. It is giving us a method of conduct. The only thing that science accepts without question is that the world itself is intelligible. When a sci-
(290) -entific law has been proved to be incorrect, it is reconstructed. The process of intelligence, then, is one of conduct which is continually adjusting itself to new situations. Therefore, it is continually changing its technique. That is what we mean by "intelligence": the control over conduct by past experience; the ability to adjust one's self to a new situation; adjusting one's past experience to meet this new situation. If there were no new situations, our conduct would be entirely habitual. What we term "consciousness" would disappear. We would simply become machines. Conscious beings are those that are continually adjusting themselves, using their past experience, reconstructing their methods of conduct. That is what we are doing all the time. That is what intelligence consists in, not in finding out once and for all what the order of nature is and then acting in certain prescribed forms, but rather in continual readjustment. The theory of evolution, you see, was a statement of this from the point of view of life.
Science, then, is not simply an advance from one theory to another, is not the erecting of a structure of laws simply to pull them down the next moment. Science is an expression of the highest type of intelligence, a method of continually adjusting itself to that which is new. You can immediately see that this attitude involves a different view of the universe from that which is presented by dogmatic disciplines. As far as our experience is concerned, if everything novel were abandoned, experience itself would cease. That is, our conduct would become habitual. just as we pay little attention to our food, just as we walk along the street without being aware of the process, or as we carry out so many of our customary tasks without giving attention to them, so in a world without novelty that in the experience of the individual which we call "consciousness" would sink toward zero value. Experience itself would cease. Our experience involves the continual appearance of that which is new. We are always advancing into a future which is different from the past. In fact, if it were not, the very meaning of the passage would disappear. The conception of the mechanical
(291) statement of the universe which Newton gave was of a universe made up of physical particles governed by very few and very simple laws. There were movements of these particles; but they were tending, as we have seen from the conception of entropy, toward a condition of stagnation, of very slight movements. Changes were tending to balance each other; they were moving toward a situation in which there would be no change at all. That mechanical statement, as everybody felt, took the meaning out of life. If you state the world in purely mechanical terms, then you have a single law for the whole of it, and it is practically the same. The same kind of energy can be somewhat differently distributed, but it is uniform. It gives a static sort of picture of the universe. The point of view which comes in with scientific method implies that, so far as our experience is concerned, the world is always different. Each morning we open our eyes upon a different universe. Our intelligence is occupied with continued adjustment to these differences. That is what makes the interest in life. We are advancing constantly into a new universe; and, not only is the universe that we look forward into new, but, as we look back, we reinterpret the old universe. We have continually a different past. Every generation re-writes its history. Novelty reaches out in both directions from each present experience.
