It is affirmed by the advocates of this hypothesis that "the grand principle of the uniformity and constancy of natural causes is a primary law of belief so strongly entertained by the truly inductive inquirer that he can not conceive the possibility of its failure."[234] As science extends her domain and pushes her discoveries into new regions, cases that once seemed anomalous are found to be conformable to this general rule, and therefore we are justified in assuming the absolute uniformity and inviolability of natural law through all the realms of time and space. Thus we reach "the grand inductive conclusion of the universal and eternal order of nature." But an overruling providence must step beyond ordinary rule: it must control, interrupt, modify, or in some manner give a new direction to the action of nature, and thus become supernatural—that is, miraculous. So that were we even to concede the phenomenal reality of the miracles recorded in the New Testament, and to accept them as "objects of faith, but not as the evidences of faith," still modern science would forbid us to believe that any supernatural interposition can now take place. Not a single instance of counteraction or control of natural law can now be authenticated, and therefore we must regard special providence as incredible and impossible.
The first error, and indeed the fundamental error, of this hypothesis is the assumption that the absolute uniformity and permanence of nature is "a primary law of belief," and therefore the natural philosopher "must set out with clear ideas of the possible and the impossible."
Now we grant that had we such à priori conviction of the permanence and immutability of nature, then it would be impossible to prove that the order of nature had a beginning, or that there could be any interference with the agencies or laws of nature by a supernatural power. "No evidence adduced in favor of a creation or of Divine interposition could ever be so strong as to overcome the necessary belief in direct opposition to it."[235] But the truth is, we have no such intuitive conviction. Our belief has none of the characteristics of an à priori intuition: it is neither self-evident nor universal nor necessary. John Stuart Mill has successfully shown that this belief is the result of experience, that it is entertained only by the cultivated and educated few, and that even among such it has been of slow growth. Therefore he properly concludes that "the uniformity in the succession of events ... must be received, not as the law of the universe, but of that portion only which is within the range of our means of observation, with a reasonable degree of extension to adjacent cases."[236]
Belief in the uniformity of nature is an induction from experience, and not a primary intuition. And by the word experience, in this connection, we must understand not the experience of one man only, or of one generation, but the accumulated experience of mankind in all ages as registered in books or transmitted by tradition. But how limited, at best, is human experience—how circumscribed both in time and space! Compared with the vastness and duration of the universe, it is narrowed down to a mere point. All experience, be it that of the individual or of mankind, is only finite. To infer a universal law from a limited number of instances is to violate to the uttermost the fundamental canon of logic that "no conclusion must contain more than was contained in the premises from which it is drawn."[237] Inductive science can only give us the contingent and the relative, it can never attain to the necessary and the absolute. By abstraction, comparison, and generalization it may furnish us with general notions, but it can not give us universal principles. "Experience can not conduct us to universal and necessary truths—not to universal, because she has not tried all cases; not to necessary, because necessity is not a matter to which experience can testify."[238] The intuitive reason, we doubt not, is furnished with necessary and universal principles which may illuminate the pathway of experience, and give meaning and law to the facts of sensation, so that man may become "the Interpreter of Nature;" but certainly the absolute uniformity of nature is not one of these ideas.
Notwithstanding the boasted mathematical precision of the inductive method, and the rigid exactness of its results, scientific men are not wholly exempt from the common infirmity of hasty generalization. They are perpetually liable to the temptation to draw immense conclusions from premises that are too narrow and inadequate. The history of science is a record of the correction of hasty generalizations by future discoveries, and leads to the final conviction that there are no laws of nature which can lay claim to absolute universality. Since the time of Newton, the law of gravitation has been regarded by many as strictly universal. But now we are told by Herschel that "our evidence of the existence of gravitation fails us beyond the region of the double stars, or leaves us at best only a presumption amounting to moral conviction in its favor." Furthermore, in regard to the luminiferous ether, he tells us that "we are freed from the necessity of any mental reference to the actual weight or specific gravity of the material, which in this case is the more necessary, as, though we suppose the ethereal molecules to possess inertia, we can not suppose them affected by the force of gravitation." "Beyond all doubt, the widest and most interesting prospect of future discovery ... is that distinction between gravitating and levitating matter, that positive and unrefutable demonstration of the existence of a repulsive force ... enormously more powerful than the attractive force of gravity."[239]
Until recently the presence of free oxygen as the necessary condition of life has been regarded as a universal biological law. "But the latest researches of Pasteur have shown that, so far from oxygen being essential to the life of the simplest living beings, there are certain forms of infusoria which not only pass their lives without oxygen, but are killed by its presence."[240]
Other illustrations might be adduced, but these are sufficient for our purpose. The truth is, there is not a phenomenon known to man that can properly be said to be the result of the action of one invariable and universal force, not even the falling of a stone to the earth; for some force must have previously been exerted to raise the stone from the earth, which force is represented by energy of position, or "potential energy."[241] And this potential energy is the exact numerical equivalent of the energy of motion which it acquires in falling—i. e., the mass multiplied by the square of the velocity. Every event, every change in nature, is due to "some variable combinations of invariable forces."[242] Material causes are always complex. Every law of nature is liable to counteraction and modification by other laws, and the most fundamental fact of the universe is that material forces are adjusted, combined, and modified in endless modes in order to the fulfillment of purposes and ends. The phenomena of life present a vast series of such adjustments and modifications. The mechanical and chemical forces are controlled and subordinated by the vital force, so that life has been defined as "a resistance to the physical forces of matter"[243]—a resistance which Liebig regards as in a certain degree invincible. Living matter is the seat of energy, and so long as it is living, can overcome the primary law of the inertia of matter, and moves spontaneously.[244] Living matter overcomes the attraction of gravitation, and resists, suspends, and modifies the action of chemical affinity.[245] It is in direct opposition to chemical affinity that organized beings exist.
Thus the various forms of energy are mutually conditioned. The mechanical, chemical, and electrical energies are counteracted by the vital force. And all the forces and energies of nature are controlled and subordinated by a higher force which orders means to ends, and adapts structure to function, viz., an Intelligent Will. The conviction finally becomes irresistible that nature is a system of things designed to be subject to Mind, and that a law of design is the highest law of the universe.
It must now be obvious that we can reach no definite conclusion in regard to the question under discussion—the uniformity of nature—unless we have a clear and precise conception of the meaning of the term "nature." The word is employed, even by men of science, in a very loose and ambiguous sense. At one time it is used to denote the totality of sensible phenomena; at another, the conditions or causes of phenomena; again, the relations of phenomena; and often, all these collectively. We must endeavor to extricate ourselves from this confusion.
According to its derivation, nature (natura—nascitur) means that which is born or produced—the becoming; that which has a beginning and an end; that which has not the cause of its existence in itself, and the cause of which must be sought in something antecedent to and beyond itself—that is, nature is the phenomenal. This the word itself expresses in the strongest manner. That which begins to be, as the necessary consequence of antecedent conditions, is natural. The co-existence, resemblance, and succession of phenomena constitute the order of nature; and the uniformity of these relations among phenomena are the laws of nature. So much is clear from the stand-point of mere empirical science. Now if law is "the uniformity of relations among phenomena,"[246] then it is equally clear that the phrase "uniformity of natural law" is meaningless, for, by the definition, the uniformity itself is the law, and the expression is simply equivalent to "the uniformity of the uniformity," which is absurd. Furthermore, if "nature" is the phenomenal—the becoming—then the word can not be properly employed to denote the causes of that becoming, unless by causes we understand antecedent conditions, which, as we shall presently see, are not real causes. Nature, or the sum-total of phenomena, is an effect—an effect which demands a cause. There can be no phenomena without change, no change without motion, no motion without force, no force without Spirit, for Spirit-force is the only force of which we have any knowledge or consciousness. A rational Will, and not a blind necessity, must stand at the fountain-head of being, and uniformity in nature must be the result of reason and choice.