The System of Nature, or, the Laws of the Moral and Physical World. Volume 1

by baron d' Paul Henri Thiry Holbach

Indeed, not only the interior organ perceives the modifications it receives from without, but again it has the faculty of modifying itself; of considering the changes which take place in it, the motion by which it is agitated in its peculiar operations, from which it imbibes new perceptions and new ideas. It is the exercise of this power to fall back upon itself, that is called reflection.

From this it will appear, that for man to think and to reflect, is to feel, or perceive within himself the impressions, the sensations, the ideas, which have been furnished to his brain by those objects which give impulse to his senses, with the various changes which his brain produced on itself in consequence.

Memory is the faculty which the brain has of renewing in itself the modifications it has received, or rather, to restore itself to a state similar to that in which it has been placed by the sensations, the perceptions, the ideas, produced by exterior objects, in the exact order it received them, without any new action on the part of these objects, or even when these objects are absent; the brain perceives that these modifications assimilate with those it formerly experienced in the presence of the objects to which it relates, or attributes them. Memory is faithful, when these modifications are precisely the same; it is treacherous, when they differ from those which the organs have exteriorly experienced.

Imagination in man is only the faculty which the brain has of modifying itself, or of forming to itself new perceptions, upon the model of those which it has anteriorly received through the action of exterior objects on the senses. The brain, then, does nothing more than combine ideas which it has already formed, which it recalls to itself, from which it forms a whole, or a collection of modifications, which it has not received, which exists no-where but in itself, although the individual ideas, or the parts of which this ideal whole is composed, have been previously communicated to it, in consequence of the impulse given to the senses by exterior objects: it is thus man forms to himself the idea of centaurs, or a being composed of a man and a horse, of hyppogriffs, or a being composed of a horse with wings and a griffin, besides a thousand other objects, equally ridiculous. By memory, the brain renews in itself the sensations, the perceptions, and the ideas which it has received or generated; represents to itself the objects which have actually moved its organs. By imagination it combines them variously: forms objects in their place which have not moved its organs, although it is perfectly acquainted with the elements or ideas of which it composes them. It is thus that man, by combining a great number of ideas borrowed from himself, such as justice, wisdom, goodness, intelligence, &c. by the aid of imagination, has formed various ideal beings, or imaginary wholes, which he has called JUPITER, JUNO, BRAMAH, SATURN, &c.

Judgment is the faculty which the brain possesses of comparing with each other the modifications it receives, the ideas it engenders, or which it has the power of awakening within itself, to the end that it may discover their relations, or their effects.

Will is a modification of the brain, by which it is disposed to action, that is to say, to give such an impulse to the organs of the body, as can induce to act in a manner, that will procure for itself what is requisite to modify it in a mode analogous to its own existence, or to enable it to avoid that by which it can be injured. To will is to be disposed to action. The exterior objects, or the interior ideas, which give birth to this disposition are called motives, because they are the springs or movements which determine it to act, that is to say, which give play to the organs of the body. Thus, voluntary actions are the motion of the body, determined by the modification of the brain. Fruit hanging on a tree, through the agency of the visual organs, modifies the brain in such a manner as to dispose the arm to stretch itself forth to cull it; again, it modifies it in another manner, by which it excites the hand to carry it to the mouth.

All the modifications which the interior organ or the brain receives, all the sensations, all the perceptions, all the ideas that are generated by the objects which give impulse to the senses, or which it renews within itself by its own peculiar faculties, are either favourable or prejudicial to man's mode of existence, whether that be transitory or habitual: they dispose the interior organ to action, which it exercises by reason of its own peculiar energy: this action is not, however, the same in all the individuals of the human species, depending much on their respective temperaments. From hence the PASSIONS have their birth: these are more or less violent; they are, however, nothing more than the motion of the will, determined by the objects which give it activity; consequently composed of the analogy or of the discordance which is found between these objects, man's peculiar mode of existence, and the force of his temperament. From this it results, that the passions are modes of existence or modifications of the brain; which either attract or repel those objects by which man is surrounded; that consequently they are submitted in their action to the physical laws of attraction and repulsion.

The faculty of perceiving or of being modified, as well by itself as exterior objects which the brain enjoys is sometimes designated by the term understanding. To the assemblage of the various faculties of which this interior organ is susceptible, is applied the name of intelligence. To a determined mode in which the brain exercises the faculties peculiar to itself, is given the appellation of reason. The dispositions or the modifications of the brain, some of them constant, others transitory, which give impulse to the beings of the human species, causing them to act, are styled wit, wisdom, goodness, prudence, virtue, &c.

In short, as there will be an opportunity presently to prove, all the intellectual faculties—that is to say, all the modes of action attributed to the soul, may be reduced to the modifications, to the qualities, to the modes of existence, to the changes produced by the motion of the brain; which is visibly in man the seat of feeling, the principle of all his actions. These modifications are to be attributed to the objects that strike on his senses; of which the impression is transmitted to the brain, or rather to the ideas, which the perceptions caused by the action of these objects on his senses have there generated, and which it has the faculty to re-produce. This brain moves itself in its turn, re-acts upon itself, gives play to the organs, which concentrate themselves in it, or which are rather nothing more than an extension of its own peculiar substance. It is thus the concealed motion of the interior organ, renders itself sensible by outward and visible signs. The brain, affected by a modification which is called FEAR, diffuses a paleness over the countenance, excites a tremulous motion in the limbs called trembling. The brain, affected by a sensation of GRIEF, causes tears to flow from the eyes, even without being moved by any exterior object; an idea which it retraces with great strength, suffices to give it very little modifications, which visibly have an influence on the whole frame.

In all this, nothing more is to be perceived than the same substance which acts diversely on the various parts of the body. If it be objected that this mechanism does not sufficiently explain the principles of the motion or the faculties of the soul; we reply, that it is in the same situation as all the other bodies of Nature, in which the most simple motion, the most ordinary phenomena, the most common modes of action are inexplicable mysteries, of which we shall never be able to fathom the first principles. Indeed, how can we flatter ourselves we shall ever be enabled to compass the true principle of that gravity by which a stone falls? Are we acquainted with the mechanism which produces attraction in some substances, repulsion in others? Are we in a condition to explain the communication of motion from one body to another? But it may be fairly asked,—Are the difficulties that occur, when attempting to explain the manner in which the soul acts, removed by making it a spiritual being, a substance of which we have not, nor cannot form one idea, which consequently must bewilder all the notions we are capable of forming to ourselves of this being? Let us then be contented to know that the soul moves itself, modifies itself, in consequence of material causes, which act upon it which give it activity: from whence the conclusion may be said to flow consecutively, that all its operations, all its faculties, prove that it is itself material.