Again, let the experimentalist apply the test of his intelligence. The effect is a series of united diagrams solving some profound problem in geometry, or a divine page of impassioned and classical eloquence, or the elegant delineation of any particular object of nature or art, according to the specific intention of the person. Here the analysis is perfect, and realizes the exact conditions imposed by the inductive canon of difference. The circumstances are all precisely identical in both cases, save the presence of rationality and its consequent mathematical harmony in the one instance, and their absence in the other. Hence there can be no question that in human causation the attribute of reason is the actual efficient of every species of order.
Besides, even nature herself presents the same experiment in every case of total insanity. The madman is deprived of reason, but not of simple volition or bare causal power; and the consequence is utter disorder and want of method in his actions. He cannot produce mathematical effects, because he is deficient in mathematical intelligence.
The same general law is demonstrated also by the canon of agreement. Universal experience shows in every department of science, industry, literature, and art that intelligence is the invariable antecedent of order, and that the absence of that mental quality involves the corresponding absence of all regular and harmonious sequence.
It remains, however, to prove our major premise by the method of concomitant variations, the canon of which has been expressed with such clear and scientific accuracy in Mill’s Logic: “Whatever phenomenon varies in any manner whenever another phenomenon varies in some particular manner, is either a cause or an effect of that phenomenon, or is connected with it through some fact of causation.”
For instance, in the case of heat, by increasing the temperature of a body we enlarge its bulk, but by enlarging its bulk we do not increase its temperature; therefore heat must be the cause, and not the effect, of expansion. In a similar manner philosophers demonstrate the first law of motion, or uniform velocity in a straight line, by showing that retardation, or divergence, is always in the definite ratio of the obstacles encountered by the moving body.
The application of this rule to our argument, although its force cannot be augmented, gives the evidence the greatest variety and splendor. For the annals of all ages and nations, without one single exception, bear witness that, in exact proportion to the increase of rationality, the human mind has always displayed corresponding effects of beauty and order in every sphere of art and civilization. What investigators have extended the limits of natural knowledge by perfecting the science of geometry, or discovering the differential calculus, or fixing the true principia of the material universe? Not a low class of intellects with feeble faculties of reason and no broad sweep of mathematical perception, but men of the loftiest genius, such as the immortal names of Euclid, Archimedes, Leibnitz, or Newton.
But I have already spent sufficient, and perhaps the reader will think too much, time on this primary induction, which indeed, from the universality of the law, has every appearance of being self-evident. Nevertheless, this fulness of discussion was indispensable to my purpose, that being to place all the premises of the argument on a scientific rather than a popular basis. And, if I am not mistaken, we are now entitled to consider the first proposition as completely proven: “That all natural phenomena having the attributes of mathematical order and harmony to the exclusion of chance must be the effects of a cause, or of causes, possessing rationality.”
I am aware, however, of the specious objection that the general induction is too wide for the warrant of its particular instances. It may be urged that although the demonstration is perfect as to the logical relation of intelligence as a cause and harmony as the consequent, yet still we are not justified in affirming that no other cause is capable of producing the same result. For example, a hundred separate antecedents may lead to death; and many ordinary facts follow very different material or mental efficients. Upon what principles, then, it will be asked, are we enabled to pronounce the universal negative that there cannot exist any unintelligent forces in the bosom of nature entirely adequate to the production of the mathematical order which we behold in the world of time and space? I state the adverse criticism in all its strength, because it is the only answer that can be interposed by the sceptical philosopher; and, besides, it constitutes the main difficulty in the minds of the multitude. Nevertheless, it cannot claim the slightest pretension to the dignity of a scientific argument.
In the first place, I remark that the objection, if it has any semblance of validity, proves too much, as it goes to overthrow every general proposition which can possibly be framed on the subject of causation, so far as assertion can proceed from the antecedent to the consequent. It cuts off from the realms of logic, at one reckless blow, the whole category of universal as to the predication of any causal sequence even among perceptible phenomena. Nay, it also denies the legitimacy of particular affirmations in all cases of causation; for if the sceptic has the logical liberty to assume the hypothesis of unknown and invisible efficients in one instance, he may with equal plausibility do so in all; and therefore these secret and unseen causes may be the real producing antecedents of every phenomenon whatever, and thus all knowledge must be reduced to naked conjecture.
By what rule, let me inquire, are we justified in extending the sublime law of gravitation to the various planets of the solar system, and even as high as the fixed stars? Obviously for the only reason that we perceive in the magnificent evolutions of the celestial bodies the same class of effects which appertain to terrestrial attraction. And upon that identical principle we are entitled to infer the existence of a rational cause wherever we behold mathematical harmonies or the manifest evidences of intelligence and design. The most stringent canons of induction give us this right, and I can see no motive for refraining from its exercise, if the process should perchance conduct us to the recognition of a Supreme Being. But as to this last point, we have not yet advanced far enough in the discussion to venture a positive declaration.