There are not wanting various significant indications of the existence of this tendency at the present day. It is sufficiently indicated, in some quarters, by the mere omission of all reference to Mind or Spirit as distinct from Matter; and, in others, by elaborate attempts to explain all the phenomena of life and thought by means of physical agencies and organic laws. The writings of Comte, Crousse, Cabanis, and Broussais,[146] afford ample evidence of its growing prevalence in France; and although it has been said by a recent historian of Philosophy that in England there has been no formal avowal, or at least no recognized school, of Materialism, since the publication of Dr. Thomas Brown's reply to Darwin's Zoönomia, yet there is too much reason to believe that it was all along cherished by not a few private thinkers, who had imbibed the spirit of Hobbes and Priestley; and now it is beginning to speak out, in terms too unambiguous to be misunderstood, in such works as "The Purpose of Existence" and the "Letters" of Atkinson and Martineau. But apart from the opinions of individual inquirers, it must be remembered that there is a tendency in certain studies, when exclusively pursued, to generate a frame of mind which will tempt men either to adopt the theory of Materialism, or at least to attach undue importance to physical agencies and organic laws. This tendency may be observed in the study of Physiology, especially when it is combined with that of Phrenology and Animal Magnetism; not that there is any necessary or strictly logical connection between these studies and Materialism, for some of their ablest expounders, including Cabanis, Gall, and Spurzheim, have explicitly disavowed that theory; but simply that, in prosecuting such inquiries, the mind is insensibly led to bestow an undue, if not exclusive, attention on the phenomena and laws of our material organization, so as to become comparatively unmindful of what is mental, moral, and spiritual in the constitution of man. For these reasons, and considering, especially, the close connection of Materialism both with the mechanical Atheism of the past, and the hylozoic Pantheism of the present age, we deem it necessary to subject its claims to a rigorous scrutiny, in connection with the subject of our present inquiry.
What, then, is the doctrine of Materialism? What are the forms in which it has appeared, and what the ground on which it rests? How does it stand related to the question concerning the nature and existence of God, or the constitution and destiny of Man? A brief answer to these questions will be sufficient to show that this theory cannot be safely disregarded in any attempt to construct a comprehensive and conclusive argument on the first principles of Natural Theology.
SECTION I.
DISTINCT FORMS OF MATERIALISM.
The doctrine of Materialism has assumed several distinct phases or forms in the hands of its different advocates; and these must be carefully discriminated from each other, if we would either estimate aright their respective merits, or do justice to the parties by whom they have been severally maintained.
The grossest and most revolting form of Materialism is that which identifies mind with matter, and thought with motion. It denies that there is any real or radical difference between physical and moral phenomena, and affirms that life and thought are so entirely dependent on material organization, that the dissolution of the body must necessarily be the destruction of conscious existence, and that death can only be an eternal sleep. This is the doctrine of Materialism which was taught in a former age, by the author of the "Systême de la Nature," and which has recently been revived by M. Comte in France, and by Atkinson and Martineau in England. A few extracts will sufficiently illustrate its character and tendency. "Men have evidently abused the distinction," says Baron D'Holbach, "which is so often made between man physical and man moral: man moral is nothing else than that physical being considered in a certain point of view, that is, with reference to some modes of action which belong to his peculiar organization."—"The universe—that vast assemblage of everything that exists—exhibits nowhere anything else than matter and motion."—"If we are asked, what is man? we reply, that he is a material being, organized or framed so as to feel, to think, and to be affected in certain ways peculiar to himself, according to his organization."[147] More recently, M. Comte has affirmed that "the subject of all our researches is one," and that "all natural phenomena are the necessary results either of the laws of extension or of the laws of motion;" while M. Crousse is quite clear that "intelligence is a property or effect of matter," and that "body and spirit together constitute matter." In our own country, Atkinson and Martineau have not shrunk from the avowal of the same doctrine, or the adoption of the most revolting consequences that can be deduced from it. "Instinct, passion, thought, are effects of organized substances."—"Mind is the consequence or product of the material man; it is not a thing having a seat or home in the brain, but it is the manifestation or expression of the brain in action, as heat and light are of fire, and fragrance of the flower."[148]
The doctrine of Materialism, as formerly taught by Dr. Priestley and his followers, is in some respects similar to that which we have just noticed, but in other respects differs from it, if not in its essential nature, at least in its collateral adjuncts and its practical applications. It resembles the theory of D'Holbach and Comte, in so far as it affirms the doctrine of unisubstancisme, and rejects the idea of a dualism such as is implied in the common doctrine of Matter and Spirit. But it differs from that theory, inasmuch as it is combined, whether consistently or otherwise, with the recognition of a personal God, a resurrection from the dead, and a future state of reward and punishment. Dr. Priestley seems to have fluctuated for a time between two opposite extremes,—that of spiritualizing Matter, and that of materializing Mind; for, in a very remarkable passage, we find him saying, "This scheme of the immateriality of Matter, as it may be called, or rather, the mutual penetration of Matter, first occurred to my friend Mr. Mitchell on reading 'Baxter on the Immateriality of the Soul.'"[149] But at length he settled down in the fixed belief of Materialism, as he had always held the principle of unisubstancisme. He held throughout that "Man does not consist of two principles so essentially different from each other as Matter and Spirit, but the whole man is of one uniform composition; and that either the material or the immaterial part of the universal system is superfluous."[150] He attempts, therefore, to show, that sensation, perception, and thought,—the common properties of mind,—are not incompatible with extension, attraction, and repulsion, which he conceives to be the only essential properties of matter; that both classes of properties may possibly belong to the same subject; and that hence no second substance is necessary to account for and explain any of the phenomena of human nature. In this respect, his theory is precisely the same with that which has been already noticed; but the peculiarity by which it is distinguished from the Atheistic and Antichristian speculations of D'Holbach and Comte is twofold. In the first place, while he ascribes to mere matter the power of sensation, thought, and volition, he admits that these powers, and all others belonging to matter, were communicated to it at the first, and are still continued, by the Divine will, thus recognizing the doctrine both of Creation and Providence; and in the second place, while he denies the natural immortality of the soul, and even the possibility of its conscious existence in a state of separation from the body, he does not deny the immortality of man, but receives it, as well as the doctrine of future rewards and punishments, on the authority of that Divine Revelation which speaks of "the resurrection of the dead," and of "a judgment to come." In these respects, his theory is widely different from that of the "Systême de la Nature," while the two are substantially the same in so far as they relate simply to the constitution of human nature. He is not an Atheist, but a Theist, and a Theist, too, who, believing in Revelation, admits the immortality of man, and a future state of retribution. But it must be evident that as in these respects he founds entirely on the authority of Scripture, so he may be confronted with the same authority when he denies the spirituality of the soul; and in that case the question would resolve itself into one of Biblical exegesis, and would fall to be decided, not by metaphysical reasoning, but by Scriptural proofs.
Another variety of the theory is presented by Dr. Good in his "Life of Lucretius." It agrees with the doctrine of Priestley in representing the soul as material; but differs from it in holding the possible existence of the soul in a separate state, during the interval between the dissolution and resurrection of the body. It speaks of the body as being composed of gross material particles; and of the soul as consisting of more subtle, refined, and ethereal matter. This modification of the theory may be illustrated by the following extract: "Perception, consciousness, cognition, we continue to be told, are qualities which cannot appertain to matter; there must hence be a thinking and an immaterial principle; and man must still be a compound being. Yet, why thus degrade matter, the plastic and prolific creature of the Deity, beyond what we are authorized to do? Why may it not perceive, why not think, why not become conscious? What eternal and necessary impediment prevents? or what self-contradiction and absurdity is hereby implied? Let us examine Nature as she presents herself to us in her most simple and inorganized forms; let us trace her through her gradual and ascending stages of power and perfection. In its simplest form, matter evinces the desire of reciprocal union, or, as it is commonly called, the attraction of gravitation. Increase its mass, arrange it in other modifications, and it immediately evinces other powers or attractions; and these will be perpetually, and almost infinitely, varied, in proportion as we vary its combinations. If arranged, therefore, in one mode, it discloses the power of magnetism; in another, that of electricity or galvanism; in a third, that of chemical affinities; in a fourth, that of mineral assimilations. Pursue its modifications into classes of a more complex, or rather, perhaps, of a more gaseous or attenuate nature, and it will evince the power of vegetable or fibrous irritability: ascend through the classes of vegetables, and you will at length reach the strong stimulative perfection, the palpable vitality of the mimosa pudica, or the hedysarum gyrans, the former of which shrinks from the touch with the most bashful coyness, while the latter perpetually dances beneath the jocund rays of the sun. And when we have thus attained the summit of vegetable powers and vegetable life, it will require, I think, no great stretch of the imagination to conceive that the fibrous irritability of animals, as well as vegetables, is the mere result of a peculiar arrangement of simple and unirritable material atoms."—"Hence, then, animal sensation, and hence, necessarily and consequently, ideas, and a material soul or spirit, rude and confined, indeed, in its first and simplest mode of existence, but, like every other production of Nature, beautifully and progressively advancing from power to power, from faculty to faculty, from excellence to excellence, till at length it terminate in the perfection of the human mind."[151]
According to this theory, the mind is supposed to have a real existence, as a substance distinct from the grosser forms of matter, and capable even of surviving its separation from them. It is supposed to be "a combination of the most volatile auras or gases, diffused over the whole body, though traced in a more concentrate form in some organs than in others;" and it is described as "the very texture of that separate state of existence which the infallible page of Revelation clearly indicates will be ours."
A form of the theory very nearly resembling this has been recently reproduced. It consists in representing the Mind or Spirit of man, not as a mere fleeting phenomenon of the brain, or an evanescent effect of its organization, but as a distinct substantive product, generated, indeed, from matter, and partaking, therefore, of its nature, but so exquisitely subtle and ethereal that it has no resemblance to the grosser materials of the body, and admits only of being compared with the Dynamides—the imponderable elements and forces of Nature. This "spirit" is generated in man by his peculiar organization, and especially by the action of the brain; it is capable of surviving the dissolution of the body, of retaining its individual consciousness after death, of passing into new spheres of being, and of rising from lower to higher states, according to a law of eternal progression. Such is the theory of Davis, the "Poughkeepsie Seer;" and such also, with some variations, is that of the author of "The Purpose of Existence."