The miraculous nature of this boasted power should suffice to make us doubt whether the law is truly what it is said to be, a strict truth, quite different from the empirical concept, from the class, and from the description. In reality, the law is nothing but the empirical concept itself, the description, class or type, of which we have just spoken. In philosophy law is a synonym for the pure concept; in the empirical or natural sciences it is a synonym for the empirical concept; hence laws are sometimes called empirical laws, or laws of experience. If they were not empirical, they would not be naturalistic, but philosophic universals, which, as we have seen, are unfruitful in the field of the natural sciences. The law of the wolf is the empirical concept of the wolf: granted that in reality there is found one part of the representation corresponding to that concept, it is possible to conclude that the rest is also found. Thus Cuvier (to choose a very trite example), arranging the types of animals and hence the laws of the correlations of organs, was able to reconstruct from one surviving bone the complete fossil animal. In like manner, granted the chemical concept of water, H2O, and given so much of oxygen and double that quantity of hydrogen, O and H2, and submitting the two bodies to the other conditions established by chemistry, it is possible to conclude that water will be seen to appear. All naturalistic laws are of this type. Certain naturalists and theorists have reasonably protested against the division of the natural sciences into descriptive and explicative, sciences of classification and sciences of laws, and have maintained that all have one common character, namely, law. But this is not because the law is superior to the class or to the empirical concept, but because the two things are identical: the law is the empirical concept and the empirical concept is the law.
The postulate of the uniformity of nature, and its meaning.
The postulate of the constancy or uniformity of nature is the base of empirical laws or concepts. This, too, is something mysterious, before which many are ready to bow, seized with reverence and sacred terror. But that postulate is not even an hypothesis, somehow conceivable, though not yet explained and demonstrated. Ordinary thought, like philosophical thought, knows that reality is neither constant nor uniform, and indeed that it is perpetually being transformed, evolving and becoming. That constancy and uniformity, which is postulated and falsely believed to be objective reality, is the same practical necessity which leads to the neglect of differences and to the looking upon the different as uniform, the changeable as constant. The postulate of the uniformity of nature is the demand for a treatment of reality made uniform for reasons of convenience. Natura non facit saltus means: mens non facit saltus in naturae cogitatione, or, better still, memoriae usus saltus naturae cohibet.
Pretended inevitability of natural laws.
Another consequence of this is the inversion of the assertion (to be found everywhere in the rhetoric of the natural sciences) as to the inexorability and inevitability of the laws of nature. Those laws, precisely because they are arbitrary constructions of our own and give the movable as fixed, are not only not inevitable and do sometimes afford exceptions; but there is absolutely no real fact, which is not an exception to its naturalistic law. By coupling a wolf and a she-wolf we obtain a wolf cub, which will in time become a new wolf, with the appearance, the strength, and the habits of its parents. But this wolf will not be identical with its parents. Otherwise how could wolves ever evolve with the evolution of the whole of reality, of which they are an indivisible part? By chemical analysis of a litre of water we obtain H2O; but if we again combine H2O, the water that we obtain is only in a way of speaking the same as before. For that combining and recombining must have produced some modification (even though not perceived by us), and in any case changes have occurred in reality in the subsequent moment, from which the water is not separable, and therefore in the water itself taken in its concreteness. We could consequently give the following definition: the inexorable laws of nature are those that are violated at every moment, while philosophic laws are by definition those that are at every moment observed. But in what way they are observed cannot be known, save by means of history, and therefore true knowledge knows nothing of previsions; it knows only facts that have really happened; of the future there can be no knowledge. The natural sciences, which do not furnish real knowledge, have, if possible, even less right (if one may speak thus) to talk of previsions.
Yet, it will be objected, it is a fact that we all form previsions, and that without them we should neither be able to cook an egg nor to take one step out of doors. That is quite true, but those alleged previsions are merely the summary of what we know by experience to have happened, and according to which we resolve upon our action. We know what has happened. We do not know, nor do we need to know, what will happen. Were any one truly to wish to know it, he would no longer be able to move and would be seized with such perplexity before life, that he would kill himself in desperation or die of fear. The egg, which usually takes five minutes to cook in the way that suits my taste, sometimes surprises me by presenting itself to my palate after those five minutes, either as too much or too little cooked; the step taken out of doors is sometimes a fall on the threshold. Nevertheless, the knowledge of this does not prevent me from leaving the house and cooking the egg, for I must walk and take nourishment. The laws of my individual being, of my temperament, of my aptitudes, of my forces, that is, the knowledge of my past, make me resolve to undertake a journey, as I did twenty years ago, to begin work upon a statue, as I did ten years ago. Alas! I had not considered that in the meantime my legs have lost their strength and my arm has begun to tremble. By all means call the previsions made use of in these cases true or false; but do not forget that they are nothing but empirical concepts, that is to say, mnemonic devices, founded upon historical judgments. There can be no doubt that they are useful; indeed, what we maintain is that just because they are useful, they are not true. If they possess any truth, it resides in the establishment of the fact. That is to say, it does not reside in the prevision and in the law, but in the historical judgment which forms its basis.
Nature and its various meanings. Nature as passivity and negativity.
Having thus made clear the coincidence of empirical concepts and the natural sciences, we must determine exactly the meaning of the word "natural," which is used as qualifying these sciences. It has not seemed advisable to change it, since its use is so deeply rooted, although we have, on the other hand, already given its synonym in qualifying these sciences as "empirical." What is nature? The first meaning of "nature" is the "opposite" of "spirit," and designates the natural or material moment in relation to the spiritual, the mechanical in relation to the teleological moment, the negative moment in relation to the positive. Thus, in the transition from one form of the spirit to another, the inferior form is like matter, ballast, or obstacle, and so is the negation of the superior form. Hence reality is imagined as the strife of two forces, the one spiritual and the other material or natural. It is superfluous to repeat that the two forces are not two, but one, and that if the negative moment were not, the positive moment could not be. The pigeon (says Kant), which rises to take flight, may believe that had it not to vanquish the resistance of the air, it would fly still better. But the fact is that without that resistance, it would fall to earth. In this sense, there is no science of Nature (of matter, passivity, negation, etc.) distinguishable from that of Spirit, which is the science of itself and of its opposite, and the science of itself only in so far as it is also the science of its opposite.
Nature as practical activity.