most important of all questions is the one, “ For what art thou at work?" It is useless to reply, "I am merely noting down what I find in the world. I am not responsible for the facts." The answer is, "A mere note-book thou art not, but a man. These are never simply notes; thy thoughts are always transformed reality, never mere copies of reality. For thy transforming activity, as well as for thy skill in copying, thou art answerable." V. It is not then that postulates occur here and there in our thoughts, but that, without postulates, both practical life and the commonest results of theory, from the simplest impressions to the most valuable beliefs, would be for most if not all of us utterly impossible; this it is which makes active faith so prominent a subject for philosophical consideration. An imperfect reflection makes that appear as blind faith which ought to appear as postulate. Instead of saying that he takes all these things on risk, and because they are worth the risk, the natural man is persuaded by such imperfect reflection to say that he trusts very ardently that he is running no risk at all. Or again: the natural man is moved to fear any examination into the bases of his thought, because he does not wish to discover that there is any risk there. And so we live dishonestly with our thoughts. Where there is a deeper basis, that involves more than mere risk, let us find it if we can. But where we have nothing better than active faith, let us discover the fact, and see clearly just why it is worth while to act in this way. To speak more particularly of the postulates of developed science. The ancient discussions about the basis of physical knowledge of all sorts have had at least this as outcome, that it is useless to pretend to make science of any sort do without assumptions, and equally useless to undertake the demonstration of these assumptions by experience alone. No one has ever succeeded in accomplishing such a thing, and the only difference among thinkers about these assumptions is that some think it worth while to seek a transcendental basis for them all, while others insist that a transcendental basis is as impossible as a purely experimental basis is inadequate, and that in consequence we can only use the form of threat and say: Unless you make these assumptions, the spirit of science is not in you. As for the exact form that in more elaborate scientific work ought to be taken by these postulates, opinion differs very much, but an approximation to their sense may be attempted very briefly as follows. In addition to those postulates that, as we have seen, accompany and condition all thinking alike, science may be considered as making a more special assumption. This assumption has been well defined by Professor Avenarius, in his well-known essay on "Die Philosophie als Denken der Welt Gemäss dem Princip des kleinsten Kraftmasses." He regards it as an outcome of the general law of parsimony that governs all mental work. The world of phenomena is conceived at any stage in the simplest form, and the reality that we accept is for us at any time the simplest description of the phenomena as known to us. To put this view in our own way, we might say that the world is scientifically viewed as a perfectly united whole, which would, if fully known, fully satisfy our highest mental desire for continuity and perfect regularity of conception. Therefore it is that the "universal formula" of the last chapter is a conception that expresses the scientific ideal. With less perfection, harmony, and unity of thought about the world, science will never rest content so long as she continues to be science. But for this very reason science postulates that this perfect order must be already realized in the world. It is not merely that this order is the practically unattainable but still necessary ideal for our reason; but we must postulate that this order is already present in things, far off as our thought is from it. This postulate gives life to our scientific thought. Without it our search for an order that need not exist is meaningless play. This postulated order, however, if found, would mean for us relative simplicity and economy of conception. The infinite mass of phenomena would be conceived as one whole. The maximum of wealth of facts would be grasped with the minimum of mental effort. We postulate after this fashion that the world loves parsimony, even as we do. To illustrate by the case of one science. A great master of mechanical science has called it the science which gives the simplest possible description of the motions in the world. If we accept this account of mechanics, we are at once puzzled by the fact that most mechanical theories make assumptions about the forces at work in the world, and that all of them predict coming facts. But forces form no part of the experience or of the mere description of motion. And the future is not yet given to be described. How then does all this agree with the definition in question? Very well indeed. For those who assume forces to explain given motions, always assume just those forces that will directly explain, not any description at random of the motions given in experience, but the simplest possible description. Any motion being relative, never for our experience absolute, we can assume at pleasure any point in the world as the origin or point of reference that shall be regarded as at rest, and so we can get an infinite number of descriptions of any given motions. We can make any object in the world move at any desired speed or in any desired direction, simply by altering the origin to which we shall choose to refer its motion in our description thereof. But all these possible descriptions are not equally useful for the purposes of the science. Some one of them is the simplest for all the motions of the system in question; and this we regard as best expressing the actual natural truth in the matter. The assumption of just such forces as would explain this simplest system of motions as described, satisfies us. say, these forces are the real ones at work. still we know that the forces assumed only express in another form the fact that the description in question is the simplest. Is this, however, really all that the science does with the given motions? No, one thing more the science assumes, namely, that if the system of motions in question is not subject to any external influence, it will remain fundamentally and in deepest truth the same in future, that is: The simplest description of the given motions in a system of bodies that is wholly independent of the action of bodies without the system, this description is permanent for all states of the system. This assumption is needed before mechanical science can venture on any prediction, or beyond mere description of past and present motions. This is the postulate of the uniformity of nature in its mechanical shape.1 The complete present description of the world would reveal the whole future of the world. What, however, does this postulate of uniformity express for our thought? What is the philosophical outcome of it? It expresses for our thought the demand that nature shall answer our highest intellectual needs, namely, the need for simplicity and absolute unity of conception. Mechanical science can no more do without this assumption than can any other science. The ground that we have here very briefly passed over is known to all readers of modern controversy. We can only add our conviction that, as far as it goes, the foregoing view is a perfectly fair one. Whether or no there be any deeper basis for this 1 Professor Clifford, in his essay on Theories of the Physical Forces, in his Lectures and Essays, vol. i., p. 109 sqq., has undertaken to reduce this postulate to the general one of Continuity. The philosophical outcome would be the same. |