A Treatise of Human Nature · Book I · Part IV · Section V (2/3)

But though in this view of things we cannot refuse to condemn the materialists, who conjoin all thought with extension; yet a little reflection will show us equal reason for blaming their antagonists, who conjoin all thought with a simple and indivisible substance. The most vulgar philosophy informs us, that no external object can make itself known to the mind immediately, and without the interposition of an image or perception. That table, which just now appears to me, is only a perception, and all its qualities are qualities of a perception. Now the most obvious of all its qualities is extension. The perception consists of parts. These parts are so situated, as to afford us the notion of distance and contiguity; of length, breadth, and thickness. The termination of these three dimensions is what we call figure. This figure is moveable, separable, and divisible. Mobility, and separability are the distinguishing properties of extended objects. And to cut short all disputes, the very idea of extension is copied from nothing but an impression, and consequently must perfectly agree to it. To say the idea of extension agrees to anything, is to say it is extended.

The freethinker may now triumph in his turn; and having found there are impressions and ideas really extended, may ask his antagonists, how they can incorporate a simple and indivisible subject with an extended perception? All the arguments of Theologians may here be retorted upon them. Is the indivisible subject, or immaterial substance, if you will, on the left or on the right hand of the perception? Is it in this particular part, or in that other? Is it in every part without being extended? Or is it entire in any one part without deserting the rest? It is impossible to give any answer to these questions, but what will both be absurd in itself, and will account for the union of our indivisible perceptions with an extended substance.

This gives me an occasion to take anew into consideration the question concerning the substance of the soul; and though I have condemned that question as utterly unintelligible, yet I cannot forbear proposing some farther reflections concerning it. I assert, that the doctrine of the immateriality, simplicity, and indivisibility of a thinking substance is a true atheism, and will serve to justify all those sentiments, for which Spinoza is so universally infamous. From this topic, I hope at least to reap one advantage, that my adversaries will not have any pretext to render the present doctrine odious by their declamations, when they see that they can be so easily retorted on them.

The fundamental principle of the atheism of Spinoza is the doctrine of the simplicity of the universe, and the unity of that substance, in which he supposes both thought and matter to inhere. There is only one substance, says he, in the world; and that substance is perfectly simple and indivisible, and exists everywhere, without any local presence. Whatever we discover externally by sensation; whatever we feel internally by reflection; all these are nothing but modifications of that one, simple, and necessarily existent being, and are not possessed of any separate or distinct existence. Every passion of the soul; every configuration of matter, however different and various, inhere in the same substance, and preserve in themselves their characters of distinction, without communicating them to that subject, in which they inhere. The same substratum, if I may so speak, supports the most different modifications, without any difference in itself; and varies them, without any variation. Neither time, nor place, nor all the diversity of nature are able to produce any composition or change in its perfect simplicity and identity.

I believe this brief exposition of the principles of that famous atheist will be sufficient for the present purpose, and that without entering farther into these gloomy and obscure regions, I shall be able to show, that this hideous hypothesis is almost the same with that of the immateriality of the soul, which has become so popular. To make this evident, let us remember,45 that as every idea is derived from a preceding perception, it is impossible our idea of a perception, and that of an object or external existence can ever represent what are specifically different from each other. Whatever difference we may suppose betwixt them, it is still incomprehensible to us; and we are obliged either to conceive an external object merely as a relation without a relative, or to make it the very same with a perception or impression.

The consequence I shall draw from this may, at first sight, appear a mere sophism; but upon the least examination will be found solid and satisfactory. I say then, that since we may suppose, but never can conceive a specific deference betwixt an object and impression; any conclusion we form concerning the connection and repugnance of impressions, will not be known certainly to be applicable to objects; but that on the other hand, whatever conclusions of this kind we form concerning objects, will most certainly be applicable to impressions. The reason is not difficult. As an object is supposed to be different from an impression, we cannot be sure, that the circumstance, upon which we found our reasoning, is common to both, supposing we form the reasoning upon the impression. It is still possible, that the object may differ from it in that particular. But when we first form our reasoning concerning the object, it is beyond doubt, that the same reasoning must extend to the impression: And that because the quality of the object, upon which the argument is founded, must at least be conceived by the mind; and could not be conceived, unless it were common to an impression; since we have no idea but what is derived from that origin. Thus we may establish it as a certain maxim, that we can never, by any principle, but by an irregular kind of reasoning from experience,46 discover a connection or repugnance betwixt objects, which extends not to impressions; though the inverse proposition may not be equally true, that all the discoverable relations of impressions are common to objects.

To apply this to the present case; there are two different systems of being presented, to which I suppose myself under necessity of assigning some substance, or ground of inhesion. I observe first the universe of objects or of body: The sun, moon and stars; the earth, seas, plants, animals, men, ships, houses, and other productions either of art or nature. Here Spinoza appears, and tells me, that these are only modifications; and that the subject, in which they inhere, is simple, uncompounded, and indivisible. After this I consider the other system of beings, viz. the universe of thought, or my impressions and ideas. There I observe another sun, moon and stars; an earth, and seas, covered and inhabited by plants and animals; towns, houses, mountains, rivers; and in short everything I can discover or conceive in the first system. Upon my enquiring concerning these, Theologians present themselves, and tell me, that these also are modifications, and modifications of one simple, uncompounded, and indivisible substance. Immediately upon which I am deafened with the noise of a hundred voices, that treat the first hypothesis with detestation and scorn, and the second with applause and veneration. I turn my attention to these hypotheses to see what may be the reason of so great a partiality; and find that they have the same fault of being unintelligible, and that as far as we can understand them, they are so much alike, that it is impossible to discover any absurdity in one, which is not common to both of them. We have no idea of any quality in an object, which does not agree to, and may not represent a quality in an impression; and that because all our ideas are derived from our impressions. We can never, therefore, find any repugnance betwixt an extended object as a modification, and a simple uncompounded essence, as its substance, unless that repugnance takes place equally betwixt the perception or impression of that extended object, and the same uncompounded essence. Every idea of a quality in an object passes through an impression; and therefore every perceivable relation, whether of connection or repugnance, must be common both to objects and impressions.

But though this argument, considered in general, seems evident beyond all doubt and contradiction, yet to make it more clear and sensible, let us survey it in detail; and see whether all the absurdities, which have been found in the system of Spinoza, may not likewise be discovered in that of Theologians.47

First, It has been said against Spinoza, according to the scholastic way of talking, rather than thinking, that a mode, not being any distinct or separate existence, must be the very same with its substance, and consequently the extension of the universe, must be in a manner identified with that, simple, uncompounded essence, in which the universe is supposed to inhere. But this, it may be pretended, is utterly impossible and inconceivable unless the indivisible substance expand itself, so as to correspond to the extension, or the extension contract itself, so as to answer to the indivisible substance. This argument seems just, as far as we can understand it; and it is plain nothing is required, but a change in the terms, to apply the same argument to our extended perceptions, and the simple essence of the soul; the ideas of objects and perceptions being in every respect the same, only attended with the supposition of a difference, that is unknown and incomprehensible.

Secondly, It has been said, that we have no idea of substance, which is not applicable to matter; nor any idea of a distinct substance, which is not applicable to every distinct portion of matter. Matter, therefore, is not a mode but a substance, and each part of matter is not a distinct mode, but a distinct substance. I have already proved, that we have no perfect idea of substance; but that taking it for something, that can exist by itself, it is evident every perception is a substance, and every distinct part of a perception a distinct substance: And consequently the one hypothesis labours under the same difficulties in this respect with the other.

Thirdly, It has been objected to the system of one simple substance in the universe, that this substance being the support or substratum of everything, must at the very same instant be modified into forms, which are contrary and incompatible. The round and square figures are incompatible in the same substance at the same time. How then is it possible, that the same substance can at once be modified into that square table, and into this round one? I ask the same question concerning the impressions of these tables; and find that the answer is no more satisfactory in one case than in the other.

It appears, then, that to whatever side we turn, the same difficulties follow us, and that we cannot advance one step towards the establishing the simplicity and immateriality of the soul, without preparing the way for a dangerous and irrecoverable atheism. It is the same case, if instead of calling thought a modification of the soul, we should give it the more ancient, and yet more modish name of an action. By an action we mean much the same thing, as what is commonly called an abstract mode; that is, something, which, properly speaking, is neither distinguishable, nor separable from its substance, and is only conceived by a distinction of reason, or an abstraction. But nothing is gained by this change of the term of modification, for that of action; nor do we free ourselves from one single difficulty by its means; as will appear from the two following reflections.

First, I observe, that the word, action, according to this explication of it, can never justly be applied to any perception, as derived from a mind or thinking substance. Our perceptions are all really different, and separable, and distinguishable from each other, and from everything else, which we can imagine: and therefore it is impossible to conceive, how they can be the action or abstract mode of any substance. The instance of motion, which is commonly made use of to show after what manner perception depends, as an action, upon its substance, rather confounds than instructs us. Motion to all appearance induces no real nor essential change on the body, but only varies its relation to other objects. But betwixt a person in the morning walking a garden with company, agreeable to him; and a person in the afternoon enclosed in a dungeon, and full of terror, despair, and resentment, there seems to be a radical difference, and of quite another kind, than what is produced on a body by the change of its situation. As we conclude from the distinction and separability of their ideas, that external objects have a separate existence from each other; so when we make these ideas themselves our objects, we must draw the same conclusion concerning them, according to the precedent reasoning. At least it must be confessed, that having idea of the substance of the soul, it is impossible for us to tell how it can admit of such differences, and even contrarieties of perception without any fundamental change; and consequently can never tell in what sense perceptions are actions of that substance. The use, therefore, of the word, action, unaccompanied with any meaning, instead of that of modification, makes no addition to our knowledge, nor is of any advantage to the doctrine of the immateriality of the soul.

I add in the second place, that if it brings any advantage to that cause, it must bring an equal to the cause of atheism. For do our Theologians pretend to make a monopoly of the word, action, and may not the atheists likewise take possession of it, and affirm that plants, animals, men, etc. are nothing but particular actions of one simple universal substance, which exerts itself from a blind and absolute necessity? This you’ll say is utterly absurd. I own it is unintelligible; but at the same time assert, according to the principles above-explained, that it is impossible to discover any absurdity in the supposition, that all the various objects in nature are actions of one simple substance, which absurdity will not be applicable to a like supposition concerning impressions and ideas.

From these hypotheses concerning the substance and local conjunction of our perceptions, we may pass to another, which is more intelligible than the former, and more important than the latter, viz. concerning the cause of our perceptions. Matter and motion, it is commonly said in the schools, however varied, are still matter and motion, and produce only a difference in the position and situation of objects. Divide a body as often as you please, it is still body. Place it in any figure, nothing ever results but figure, or the relation of parts. Move it in any manner, you still find motion or a change of relation. It is absurd to imagine, that motion in a circle, for instance, should be nothing but merely motion in a circle; while motion in another direction, as in an ellipse, should also be a passion or moral reflection: That the shocking of two globular particles should become a sensation of pain, and that the meeting of two triangular ones should afford a pleasure. Now as these different shocks, and variations, and mixtures are the only changes, of which matter is susceptible, and as these never afford us any idea of thought or perception, it is concluded to be impossible, that thought can ever be caused by matter.