Mr. Hume's notion about cause and effect has been greatly extended by its distinguished advocate, Dr. Thomas Brown; whose acuteness, eloquence, and elevation of character, have given it a circulation which it could never have received from the influence of its author. Almost as often as divines have occasion to use this notion, they call it the doctrine of Dr. Brown, and omit to notice its true atheistical paternity and origin.
The defenders of this doctrine are directly opposed, in regard to a fundamental point, to all other necessitarians. Though they deny the existence of all power and efficacy, they still hold that human volitions are necessary; while other necessitarians ground their doctrine on the fact, that volitions are produced by [pg 076] the most powerful, the most efficacious motives. They are not only at war with other necessitarians, they are also at war with themselves. Let us see if this may not be clearly shown.
According to the scheme in question, the mind does not act upon the body, nor the body upon the mind; for there is no power, and consequently no action of power, in the universe. Now, it is known that it was the doctrine of Leibnitz, that two substances so wholly unlike as mind and matter could not act upon each other; and hence he concluded that the phenomena of the internal and external worlds were merely “conjoined, not connected.” The soul and body run together—to use his own illustration—like two independent watches, without either exerting any influence upon the movements of the other. Thus arose his celebrated, but now obsolete fiction, of a preëstablished harmony. Now, if the doctrine of Hume and Brown be true, this sort of harmony subsists, not only in relation to mind and body, but in relation to all things in existence. Mind never acts upon body, nor mind upon mind. Hence, this doctrine is but a generalization of the preëstablished harmony of Leibnitz, with the exception that Mr. Hume did not contend that this wonderful harmony was established by the Divine Being. Is it not wonderful that so acute a metaphysician as Dr. Brown should not have perceived the inseparable affinity between his doctrine and that of Leibnitz? Is it not wonderful that, instead of perceiving this affinity, he should have poured ridicule and contempt upon the doctrine of which his own was but a generalization? Mr. Mill, another able and strenuous advocate of Mr. Hume's theory of causation, has likewise ranked the preëstablished harmony of Leibnitz, as well as the system of occasional causes peculiar to Malebranche, among the fallacies of the human mind. Thus they are at war with themselves, as well as with their great coadjutors in the cause of necessity.
M. Comte, preëminently distinguished in every branch of science, has taken the same one-sided view of nature as that which is exhibited in the theory under consideration; but he does not permit himself to be encumbered by the inconsistencies observable in his great predecessors. On the contrary, he boldly carries out his doctrine to its legitimate consequences, denying the existence of a God, the free-agency of man, and the reality of moral distinctions.
Mr. Mill also refuses to avail himself of the notion of liberty entertained by Hobbes and Hume, in order to lay a foundation for human responsibility. He sees that it really cannot be made to answer such a purpose. He also sees, that the doctrine of necessity, as usually maintained, is liable to the objections urged against it, that “it tends to degrade the moral nature of man, and to paralyze our desire of excellence.”[50] In making this concession to the advocates of liberty, he speaks from his own “personal experience.” The only way to escape these pernicious consequences, he says, is to keep constantly before the mind a clear and unclouded view of the true theory of causation, which will prevent us from supposing, as most necessitarians do, that there is a real connecting link or influence between motives and volitions, or any other events. So strong is the prejudice (as he calls it) in favour of such connection, that even those who adopt Mr. Hume's theory, are not habitually influenced by it, but frequently relapse into the old error which conflicts with the free-agency and accountability of man, and hence an advantage which their opponents have had over them.
These remarks are undoubtedly just. There is not a single writer, from Mr. Hume himself, down to the present day, who has been able either to speak or to reason in conformity with his theory, however warmly he may have embraced it. Mr. Mill himself has not been more fortunate in this respect than many of his distinguished predecessors. It is an exceedingly difficult thing, by the force of speculation, to silence the voice of nature within us. If it were necessary we might easily show, that if we abstract “the common prejudice,” in regard to causation, it will be as impossible to read Mr. Mill's work on logic, as to read Mr. Hume's writings themselves, without perceiving that many of its passages have been stripped of all logical coherency of thought. The defect which he so clearly sees in the writings of other advocates of necessity, not excepting those who embrace his own paradox in relation to cause and effect, we can easily perceive in his own.
The doctrine of causation, under consideration, annihilates one of the clearest and most fundamental distinctions ever made in philosophy; the distinction between action and passion, between [pg 078] mind and matter. Matter is passive, mind is active. The very first law of motion laid down in the Principia, a work so much admired by M. Comte and Mr. Mill, is based on the idea that matter is wholly inert, and destitute of power either to move itself, or to check itself when moved by anything ab extra. This will not be denied. But is mind equally passive? Is there nothing in existence which rises above this passivity of the material world? If there is not, and such is the evident conclusion of the doctrine in question, then all things flow on in one boundless ocean of passivity, while there is no First Mover, no Self-active Agent in the universe. Indeed, Mr. Mill has expressly declared, that the distinction between agent and patient is illusory.[51] If this be true, we are persuaded that M. Comte has been more successful in delivering the world from the being of a God, than Mr. Mill has been in relieving it from the difficulties attending the scheme of necessity.