The evolution of scientific thought from Newton to Einstein

by A. D'Abro

In short, it is in the accuracy with which the facts are studied and co-ordinated, and it is in the number of facts considered, that the scientific method differs from all other methods. Therein resides its superiority. Had the great scientists confined themselves to a general line of talk based on a crude survey of a number of conspicuous facts, we might still to-day be defending Plato’s idea that earth, air, fire and water constituted the four elements, or Aristotle’s contention that the heavenly bodies described circles because circular motion was the most noble of motions, or, again, Kant’s belief that the axioms of geometry were in the nature of a priori synthetic judgments, and so forth.

Thus it may be realised that a discussion of the philosophical significance of the discoveries of physical and mathematical science must be left to the theoretical physicists and to the mathematicians. They alone, in view of their wide knowledge of facts and their mastery of the rigorous mathematical mode of thinking, are in a position to co-ordinate the apparently disconnected results furnished by experience and by reason. If, then, a super-philosophy is to be attained, it would appear that the most successful results would ensue from a work of collaboration between the scientists of the various branches of knowledge. Such collaborations are continually in progress. We need only mention the contributions of physicists like Einstein and Nernst to problems of physical chemistry; and physical chemistry is closely allied to the chemistry of colloids, hence to that of the living organisms. All these spheres of science, from mathematics to psychology, dovetail into one another, as terms like bio-chemistry, psycho-physics and physical chemistry indicate.

It might be urged that the results embodied in the special sciences do not embody all of nature; that there is mind and consciousness, that there are emotions, values in quality, religious instincts, and so on. But here it should be remembered that whatever transcends the sphere of the special sciences transcends it precisely because it is vague and only dimly apprehended. And where facts are so vague and poorly established as to be refractory to the scientific method, we generally find that there are so many different ways of co-ordinating them loosely that almost any opinion can be expressed with the same degree of plausibility. As a result, the opinion of the wise man is on a par with that of the ignoramus.

If we wish to advance at all, it would seem that the best method would be to start by considering the facts we know something positive about, rather than reverse the procedure. The results embodied in the special sciences are so numerous and (relatively speaking) so well established, that we cannot afford to consider seriously any system of philosophy which would enter into conflict with them, or ignore them.

At any rate, granted that, in the present state of our knowledge, no co-ordination of facts can be anything but extremely fragmentary, it may be presumed that the theoretical scientists who have shown such marked ability in their co-ordinations of natural facts are the men best fitted to construct a philosophy of nature. We need not be surprised, therefore, to find that their study of nature has yielded them a philosophy which, with very few exceptions, they all share in common.

In the present chapter, we shall discuss the methodology together with the philosophic views that are accepted by the vast majority of theoretical physicists. In particular, the philosophy expressed will be exemplified by the attitude of the two leading scientists of our generation: Poincaré as a mathematician, and Einstein as a physicist.

The problem of knowledge, though generally considered independently of science proper, is yet so involved with scientific considerations (some of which are by no means elementary) that it appears necessary to approach it by the usual methods of scientific investigation. By knowledge we do not wish to imply our bare awareness of sensations, such as the worm and oyster probably share in common with human beings. Sensations constitute one of the original sources of knowledge, but knowledge entails considerably more; judgment and inference enter into knowledge, and knowledge is a construct or co-ordination in which our sensations enter merely as fundamental elements. For instance, when as a result of our visual and tactual sensations we recognise that a table is there before us, we are claiming knowledge; but the visual and tactual impressions by themselves do not constitute knowledge.

The natural uncritical view would be to assume that knowledge was given directly by the disclosures of perception. Thus, when we see the table, we know it to exist “there-now” in the spatio-temporal background. But if we analyse the situation, we cannot subscribe to this view, for our recognition of the table’s existence and position in space and time appears to have been brought about in a far more complicated manner than a cursory examination might lead us to suppose. What we really experience is an aggregate of colours with a well-defined contour. Only when we wish to ascribe a cause to these sensations does the idea of a table enter our consciousness. But here again, in this search for a cause, it is only in view of past experience, in view of an association of ideas, that we feel justified in postulating the existence of the table situated there-now in the spatio-temporal background. Our judgment may be correct, but it might also be erroneous, as it would be had we been gazing at a skilful painting or at the image of a table in the mirror. Quite independently of such possible errors of judgment, the main point is that there is a decided difference between our awareness of the visual sensations and our belief in the presence of a table located there-now in space. Whereas the visual sensations do not entail as an inevitable corollary the existence of the table, yet our belief in its existence does presuppose our awareness of certain sense impressions or our memory thereof, since otherwise there would be no reason for us to postulate the table’s existence. For this reason we must credit to our awareness of sensations primacy over the so-called immediate disclosures of perception, just as we must concede to the recognition of experimental facts priority over the scientific theories constructed with a view to bringing about their co-ordination. Accordingly we shall refer to our awareness of sensations as facts.

A further illustration may make this point clearer. For example, we feel hot, and exclaim: “What a warm day!” Our awareness of a sensation of hotness constitutes a fundamental fact, but our claim that the day is warm is but an inference. We may test the warmth of the atmosphere with a thermometer, hence we may test the validity of our inference, but we cannot test our awareness of warmth. The feeling of warmth may be due to the temperature of the air, to fever or to sheer imagination, but, regardless of its cause, we know that we feel warm, and our assurance of this fact can neither be disputed nor analysed.[133]

Then again, we experience very similar sensations when our skin comes into contact with a substance at high temperature or with liquid air. If from this similarity in our sensations we should infer the identity of the temperatures involved, we should be led into error; but it would be our inferences that were at fault, and not the sensations, which subsist regardless of whether or not we choose to draw inferences therefrom.