There is then a great difference between the entities of science and the things of daily life. This may be fully acknowledged. But unless the admission is accompanied by an ignoring of the function of inference, it creates no problem of conciliation, no need of apologizing for either one or the other. It generates no problem of the real and the apparent. The "real" or "true" objects of science are those which best fulfil the demands of secure and fertile inference. To arrive at them is such a difficult operation, there are so many specious candidates clamoring for the office, that it is no wonder that when the objects suitable for inference are constituted, they tend to impose themselves as the real objects, in comparison with which the things of ordinary life are but impressions made upon us (according to much modern thought), or defective samples of Being—according to much of ancient thought. But one has only to note that their genuinely characteristic feature is fitness for the aims of inference to awaken from the nightmare of all such problems. They differ from the things of the common world of action and association as the means and ends of one occupation differ from those of another. The difference is not that which exists between reality and appearance, but is that between the subject-matter of crude occupations and of a highly specialized and difficult art, upon the success of which (so it is discovered) the progress of other occupations ultimately depends.
The entities of science are not only from the scientist; they are also for him. They express, that is, not only the outcome of reflective inquiries, but express them in the particular form in which they can enter most directly and efficiently into subsequent inquiries. The fact that they are sustained within the universe of inquiry accounts for their remoteness from the things of daily life, the latter being promptly precipitated out of suspense in such solutions. That most of the immediate qualities of things (including the so-called secondary qualities) are dropped signifies that such qualities have not turned out to be fruitful for inference. That mathematical, mechanical, and "primary" distinctions and relations have come to constitute the proper subject-matter of science signifies that they represent such qualities of original things as are most manipular for knowledge-getting or assured and extensive inference. Consider what a hard time the scientific man had in getting away from other qualities, and how the more immediate qualities have been pressed upon him from all quarters, and it is not surprising that he inclines to think of the intellectually useful properties as alone "real" and to relegate all others to a quasi-illusory field. But his victory is now sufficiently achieved so that this tension may well relax; it may be acknowledged that the difference between scientific entities and ordinary things is one of function, the former being selected and arranged for the successful conduct of inferential knowings.
I conclude with an attempt to show how bootless the ordinary antithesis between knowledge (or theory) and practice becomes when we recognize that it really involves only a contrast between the kinds of judgments appropriate to ordinary modes of practice and those appropriate to the specialized industry of knowledge-getting.
It is not true that to insist that scientific propositions fall within the domain of practice is to depreciate them. On its face, the insistence means simply that all knowledge involves experimentation, with whatever appliances are suited to the problem in hand, of an active and physical type. Instead of this doctrine leading to a low estimate of knowledge, the contrary is the case. This art of experimental thinking turns out to give the key to the control and development of other modes of practice. I have touched elsewhere in these essays upon the way in which knowledge is the instrument of regulation of our human undertakings, and I have also pointed out that intrinsic increments of meaning accrue in consequence of thinking. I wish here to point how that mode of practice which is called theorizing emancipates experience—how it makes for steady progress. No matter how much specialized skill improves, we are restricted in the degree in which our ends remain constant or fixed. Significant progress, progress which is more than technical, depends upon ability to foresee new and different results and to arrange conditions for their effectuation. Science is the instrument of increasing our technique in attaining results already known and cherished. More important yet, it is the method of emancipating us from enslavement to customary ends, the ends established in the past.
Let me borrow from political philosophy a kind of caricature of the facts. As social philosophers used to say that the state came into existence when individuals agreed to surrender some of their native personal rights for the sake of getting the advantages of non-interference and aid from others who made a like surrender, so we might say that science began when men gave up the claim to form the structure of knowledge each from himself as a center and measure of meaning—when there was an agreement to take an impersonal standpoint. Non-scientific modes of practice, left to their natural growth, represent, in other words, arrangements of objects which cluster about the self, and which are closely tied down to the habits of the self. Science or theory means a system of objects detached from any particular personal standpoint, and therefore available for any and every possible personal standpoint. Even the exigencies of ordinary social life require a slight amount of such detachment or abstraction. I must neglect my own peculiar ends enough to take some account of my neighbor if I am going to be intelligible to him. I must at least find common ground. Science systematizes and indefinitely extends this principle. It takes its stand, not with what is common with some particular neighbor living at this especial date in this particular village, but with any possible neighbor in the wide stretches of time and space. And it does so by the mere fact that it is continually reshaping its peculiar objects with an eye single to availability in inference. The more abstract, the more impersonal, the more impartially objective are its objects, the greater the variety and scope of inference made possible. Every street of experience which is laid out by science has its tracks for transportation, and every line issues transfer checks to every other line. You and I may keep running in certain particular ruts, but conditions are provided for somebody else to foresee—or infer—new combinations and new results. The depersonalizing of the things of everyday practice becomes the chief agency of their repersonalizing in new and more fruitful modes of practice. The paradox of theory and practice is that theory is with respect to all other modes of practice the most practical of all things, and the more impartial and impersonal it is, the more truly practical it is. And this is the sole paradox.
But lest the man of science, the man of dominantly reflective habits, be puffed up with his own conceits, he must bear in mind that practical application—that is, experiment—is a condition of his own calling, that it is indispensable to the institution of knowledge or truth. Consequently, in order that he keep his own balance, it is needed that his findings be everywhere applied. The more their application is confined within his own special calling, the less meaning do the conceptions possess, and the more exposed they are to error. The widest possible range of application is the means of the deepest verification. As long as the specialist hugs his own results they are vague in meaning and unsafe in content. That individuals in every branch of human endeavor should be experimentalists engaged in testing the findings of the theorist is the sole final guaranty for the sanity of the theorist.