Philosophical Works, v. 1 · David Hume
OF THE IMMATERIALITY OF THE SOUL.
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 'tis 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_, 'tis 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.
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 every thing else which we can imagine; and therefore, 'tis 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 in 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 no idea of the substance of the soul, 'tis 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 other plants, animals, men, &c., 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 'tis unintelligible; but, at the same time assert, according to the principles above explained, that 'tis 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, 'tis 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, 'tis 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. 'Tis 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, 'tis concluded to be impossible, that thought can ever be caused by matter.
Few have been able to withstand the seeming evidence of this argument; and yet nothing in the world is more easy than to refute it. We need only reflect on what has been proved at large, that we are never sensible of any connexion betwixt causes and effects, and that 'tis only by our experience of their constant conjunction, we can arrive at any knowledge of this relation. Now, as all objects, which are not contrary, are susceptible of a constant conjunction, and as no real objects are contrary; I have inferred from these principles,[14] that to consider the matter _a priori_, any thing may produce any thing, and that we shall never discover a reason, why any object may or may not be the cause of any other, however great, or however little the resemblance may be betwixt them. This evidently destroys the precedent reasoning concerning the cause of thought or perception. For though there appear no manner of connexion betwixt motion or thought, the case is the same with all other causes and effects.
Place one body of a pound weight on one end of a lever, and another body of the same weight on another end; you will never find in these bodies any principle of motion dependent on their distances from the centre, more than of thought and perception. If you pretend, therefore, to prove, _a priori_, that such a position of bodies can never cause thought; because, turn it which way you will, 'tis nothing but a position of bodies; you must, by the same course of reasoning conclude, that it can never produce motion; since there is no more apparent connexion in the one case than in the other. But as this latter conclusion is contrary to evident experience, and as 'tis possible we may have a like experience in the operations of the mind, and may perceive a constant conjunction of thought and motion; you reason too hastily, when, from the mere consideration of the ideas, you conclude that 'tis impossible motion can ever produce thought, or a different position of parts give rise to a different passion or reflection. Nay, 'tis not only possible we may have such an experience, but 'tis certain we have it; since every one may perceive, that the different dispositions of his body change his thoughts and sentiments.
And should it be said, that this depends on the union of soul and body, I would answer, that we must separate the question concerning the substance of the mind from that concerning the cause of its thought; and that, confining ourselves to the latter question, we find, by the comparing their ideas, that thought and motion are different from each other, and by experience, that they are constantly united; which being all the circumstances that enter into the idea of cause and effect, when applied to the operations of matter, we may certainly conclude, that motion may be, and actually is, the cause of thought and perception. There seems only this dilemma left us in the present case; either to assert, that nothing can be the cause of another, but where the mind can perceive the connexion in its idea of the objects: or to maintain, that all objects which we find constantly conjoined, are upon that account to be regarded as causes and effects. If we choose the first part of the dilemma, these are the consequences. _First_, we in reality affirm, that there is no such thing in the universe as a cause or productive principle, not even the Deity himself; since our idea of that Supreme Being is derived from particular impressions, none of which contain any efficacy, nor seem to have _any_ connexion with _any_ other existence. As to what may be said, that the connexion betwixt the idea of an infinitely powerful Being and that of any effect, which he wills, is necessary and unavoidable; I answer, that we have no idea of a Being endowed with any power, much less of one endowed with infinite power.
But if we will change expressions, we can only define power by connexion; and then in saying, that the idea of an infinitely powerful Being is connected with that of every effect which he wills, we really do no more than assert, that a Being, whose volition is connected with every effect, is connected with every effect; which is an identical proposition, and gives us no insight into the nature of this power or connexion. But, _secondly_, supposing that the Deity were the great and efficacious principle which supplies the deficiency of all causes, this leads us into the grossest impieties and absurdities. For upon the same account that we have recourse to him in natural operations, and assert that matter cannot of itself communicate motion, or produce thought, viz. because there is no apparent connexion betwixt these objects; I say, upon the very same account, we must acknowledge that the Deity is the author of all our volitions and perceptions; since they have no more apparent connexion either with one another, or with the supposed but unknown substance of the soul. This agency of the Supreme Being we know to have been asserted by several philosophers[15] with relation to all the actions of the mind, except volition, or rather an inconsiderable part of volition; though 'tis easy to perceive, that this exception is a mere pretext, to avoid the dangerous consequences of that doctrine. If nothing be active but what has an apparent power, thought is in no case any more active than matter; and if this inactivity must make us have recourse to a Deity, the Supreme Being is the real cause of all our actions, bad as well as good, vicious as well as virtuous.
Thus we are necessarily reduced to the other side of the dilemma, viz. that all objects, which are found to be constantly conjoined, are upon that account only to be regarded as causes and effects. Now, as all objects which are not contrary, are susceptible of a constant conjunction, and as no real objects are contrary; it follows, that, for ought we can determine by the mere ideas, any thing may be the cause or effect of any thing; which evidently gives the advantage to the materialists above their antagonists. To pronounce, then, the final decision upon the whole: the question concerning the substance of the soul is absolutely unintelligible: all our perceptions are not susceptible of a local union, either with what is extended or unextended; there being some of them of the one kind, and some of the other: and as the constant conjunction of objects constitutes the very essence of cause and effect, matter and motion may often be regarded as the causes of thought, as far as we have any notion of that relation. 'Tis certainly a kind of indignity to philosophy, whose sovereign authority ought every where to be acknowledged, to oblige her on every occasion to make apologies for her conclusions, and justify herself to every particular art and science, which may be offended at her. This puts one in mind of a king arraigned for high treason against his subjects. There is only one occasion when philosophy will think it necessary and even honourable to justify herself; and that is, religion may seem to be in the least offended; whose rights are as dear to her as her own, and are indeed the same. If any one, therefore, should imagine that the foregoing arguments are any ways dangerous to religion, I hope the following apology will remove his apprehensions.
There is no foundation for any conclusion _a priori_, either concerning the operations or duration of any object, of which 'tis possible for the human mind to form a conception. Any object may be imagined to become entirely inactive, or to be annihilated in a moment; and 'tis an evident principle, _that whatever we can imagine is possible_. Now this is no more true of matter, than of spirit; of an extended compounded substance, than of a simple and unextended. In both cases the metaphysical arguments for the immortality of the soul are equally inconclusive; and in both cases the moral arguments and those derived from the analogy of nature are equally strong and convincing. If my philosophy therefore makes no addition to the arguments for religion, I have at least the satisfaction to think it takes nothing from them, but that every thing remains precisely as before. [9] Part I. Sect. 5. [10] Sect 2, towards the end. [11] Part. II. Sect. 6. [12] Such as that of Sect. 2, from the coherence of our perceptions. [13] See Bayle's Dictionary, article of Spinoza. [14] Part III. sect. 15. [15] As Father Malebranche and other Cartesians.
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