David Hume

“ When my perceptions are remov’d for any time, as by sound sleep; so long am I insensible of myself, and may truly be said not to exist. And were all my perceptions remov’d by death, and cou’d I neither think, nor feel, nor see, nor love, nor hate after the dissolution of my body, I shou’d be entirely annihilated, nor do I conceive what is farther requisite to make me a perfect non-entity. If any one, upon serious and unprejudic’d reflection thinks he has a different notion of himself, I must confess I call reason no longer with him. ”

“ Every one keeps at a distance, and dreads that storm, which beats upon me from every side. I have expos’d myself to the enmity of all metaphysicians, logicians, mathematicians, and even theologians; and can I wonder at the insults I must suffer? I have declar’d my disapprobation of their systems; and can I be surpriz’d, if they shou’d express a hatred of mine and of my person? When I look abroad, I foresee on every side, dispute, contradiction, anger, calumny and detraction. When I turn my eye inward, I find nothing but doubt and ignorance. All the world conspires to oppose and contradict me ”

“ And how must we be disappointed, when we learn, that this connexion, tie, or energy lies merely in ourselves, and is nothing but that determination of the mind, which is acquir’d by custom, and causes us to make a transition from an object to its usual attendant, and from the impression of one to the lively idea of the other? Such a discovery not only cuts off all hope of ever attaining satisfaction, but even prevents our very wishes ”

“ Our thought is still more variable than our sight; and all our other senses and faculties contribute to this change; nor is there any single power of the soul, which remains unalterably the same, perhaps for one moment. The mind is a .kind of theatre, where several perceptions successively make their appearance; pass, re-pass, glide away, and mingle in an infinite variety of postures and situations. There is properly no simplicity in it at one time, nor identity in different; whatever natural propension we may have to imagine that simplicity and identity. ”

“ 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 every where, 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 possest of any separate or distinct existence. ”

“ This sceptical doubt, both with respect to reason and the senses, is a malady, which can never be radically cur’d, but must return upon us every moment, however we may chace it away, and sometimes may seem entirely free from it. ‘Tis impossible upon any system to defend either our understanding or senses; and we but expose them farther when we endeavour to justify them in that manner. As the sceptical doubt arises naturally from a profound and intense reflection on those subjects, it always encreases, the farther we carry our reflections, whether in opposition or conformity to it. ”

“ The opinions of the antient philosophers, their fictions of substance and accident, and their reasonings concerning substantial forms and occult qualities, are like the spectres in the dark, and are deriv’d from principles, which, however common, are neither universal nor unavoidable in human nature. The modern philosophy pretends to be entirely free from this defect, and to arise only from the solid, permanent, and consistent principles of the imagination. ”

“ We have no perfect idea of any thing but of a perception. A substance is entirely different from a perception. We have, therefore, no idea of a substance. Inhesion in something is suppos’d to be requisite to support the existence of our perceptions. Nothing appears requisite to support the existence of a perception. We have, therefore, no idea of inhesion. What possibility then of answering that question, Whether perceptions inhere in a material or immaterial substance, when we do not so much as understand the meaning of the question? ”

“ There is only one occasion, when philosophy will think it necessary and even honourable to justify herself, and that is, when 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, shou’d 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. ”

“ In every judgment, which we can form concerning probability, as well as concerning knowledge, we ought always to correct the first judgment, deriv’d from the nature of the object, by another judgment, deriv’d from the nature of the understanding. ‘Tis certain a man of solid sense and long experience ought to have, and usually has, a greater assurance in his opinions, than one that is foolish and ignorant, and that our sentiments have different degrees of authority, even with ourselves, in proportion to the degrees of our reason and experience. ”

“ 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 deriv’d 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 endow’d with any power, much less of one endow’d with infinite power. ”

“ For as such a succession answers evidently to our notion of diversity, it can only be by mistake we ascribe to it an identity; and as the relation of parts, which leads us into this mistake, is really nothing but a quality, which produces an association of ideas, and an easy transition of the imagination from one to another, it can only be from the resemblance, which this act of the mind bears to that, by which we contemplate one continu’d object, that the error arises. ”

“ In order to form an idea of solidity, we must conceive two bodies pressing on each other without any penetration; and ‘tis impossible to arrive at this idea, when we confine ourselves to one object, much more without conceiving any. Two non-entities cannot exclude each other from their places; because they never possess any place, nor can be endow’d with any quality. Now I ask, what idea do we form of these bodies or objects, to which we suppose solidity to belong? To say, that we conceive them merely as solid, is to run on in infinitum. ”

“ The impressions, which enter by the sight and hearing, the smell and taste, are affirm’d by modern philosophy to be without any resembling objects; and consequently the idea of solidity, which is suppos’d to be real, can never be deriv’d from any of these senses. There remains, therefore, the feeling as the only sense, that can convey the impression, which is original to the idea of solidity; and indeed we naturally imagine, that we feel the solidity of bodies, and need but touch any object in order to perceive this quality. But this method of thinking is more popular than philosophical ”

“ The imagination is seduc’d into such an opinion only by means of the resemblance of certain perceptions; since we find they are only our resembling perceptions, which we have a propension to suppose the same. This propension to bestow an identity on our resembling perceptions, produces the fiction of a continu’d existence; since that fiction, as well as the identity, is really false, as is acknowledged by all philosophers, and has no other effect than to remedy the interruption of our perceptions, which is the only circumstance that is contrary to their identity. ”

“ The straining of the imagination always hinders the regular flowing of the passions and sentiments. A tragic poet, that wou’d represent his heroes as very ingenious and witty in their misfortunes, wou’d never touch the passions. As the emotions of the soul prevent any subtile reasoning and reflection, so these latter actions of the mind are equally prejudicial to the former. The mind, as well as the body, seems to be endow’d with a certain precise degree of force and activity, which it never employs in one action, but at the expense of all the rest. ”

“ A single perception can never produce the idea of a double existence, but by some inference either of the reason or imagination. When the mind looks farther than what immediately appears to it, its conclusions can never be put to the account of the senses; and it certainly looks farther, when from a single perception it infers a double existence, and supposes the relations of resemblance and causation betwixt them.
If our senses, therefore, suggest any idea of distinct existences, they must convey the impressions as those very existences, by a kind of fallacy and illusion. ”

“ A change in any considerable part of a body destroys its identity; but ‘tis remarkable, that where the change is produc’d gradually and insensibly we are less apt to ascribe to it the same effect. The reason can plainly be no other, than that the mind, in following the successive changes of the body, feels an easy passage from the surveying its condition in one moment to the viewing of it in another, and at no particular time perceives any interruption in its actions. From which continu’d perception, it ascribes a continu’d existence and identity to the object. ”

“ When we trace up the human understanding to its first principles, we find it to lead us into such sentiments, as seem to turn into ridicule all our past pains and industry, and to discourage us from future enquiries. Nothing is more curiously enquir’d after by the mind of man, than the causes of every phenomenon; nor are we content with knowing the immediate causes, but push on our enquiries, till we arrive at the original and ultimate principle. We wou’d not willingly stop before we are acquainted with that energy in the cause, by which it operates on its effect ”

“ Thus there is a direct and total opposition betwixt our reason and our senses; or more properly speaking, betwixt those conclusions we form from cause and effect, and those that persuade us of the continu’d and independent existence of body. When we reason from cause and effect, we conclude, that neither colour, sound, taste, nor smell have a continu’d and independent existence. When we exclude these sensible qualities there remains nothing in the universe, which has such an existence. ”

“ We may observe, then, that ‘tis neither upon account of the involuntariness of certain impressions, as is commonly suppos’d, nor of their superior force and violence, that we attribute to them a reality, and continu’d existence, which we refuse to others, that are voluntary or feeble. For ‘tis evident our pains and pleasures, our passions and affections, which we never suppose to have any existence beyond our perception, operate with greater violence, and are equally involuntary, as the impressions of figure and extension, colour and sound, which we suppose to be permanent beings. ”

“ We cannot, in any propriety of speech, say, that an object is the same with itself, unless we mean, that the object existent at one time is the same with itself existent at another. By this means we make a difference, betwixt the idea meant by the word, object, and that meant by itself, without going the length of number, and at the same time without restraining ourselves to a strict and absolute unity. ”

“ If it exist within its dimensions, it must either exist in one particular part; and then that particular part is indivisible, and the perception is conjoined only with it, not with the extension: Or if the thought exists in every part, it must also be extended, and separable, and divisible, as well as the body; which is utterly absurd and contradictory. For can any one conceive a passion of a yard in length, a foot in breadth, and an inch in thickness? Thought, therefore, and extension are qualities wholly incompatible, and never can incorporate together into one subject. ”

“ When we diminish or encrease a relish, ‘tis not after the same manner that we diminish or encrease any visible object; and when several sounds strike our hearing at once, custom and reflection alone make us form an idea of the degrees of the distance and contiguity of those bodies, from which they are deriv’d. Whatever marks the place of its existence either must be extended, or must be a mathematical point, without parts or composition. ”

“ But among all the instances, wherein the Peripatetics have shewn they were guided by every trivial propensity of the imagination, no one is more remarkable than their sympathies, antipathies, and horrors of a vacuum. There is a very remarkable inclination in human nature, to bestow on external objects the same emotions, which it observes in itself; and to find every where those ideas, which are most present to it. This inclination, ‘tis true, is suppressed by a little reflection, and only takes place in children, poets, and the antient philosophers. ”

“ There is a great difference betwixt such opinions as we form after a calm and profound reflection, and such as we embrace by a kind of instinct or natural impulse, on account of their suitableness and conformity to the mind. If these opinions become contrary, ‘tis not difficult to foresee which of them will have the advantage. As long as our attention is bent upon the subject, the philosophical and study’d principle may prevail; but the moment we relax our thoughts, nature will display herself, and draw us back to our former opinion. ”

“ When we look along the insensible changes of bodies, we suppose all of them to be of the same substance or essence. When we consider their sensible differences, we attribute to each of them a substantial and essential difference. And in order to indulge ourselves in both these ways of considering our objects, we suppose all bodies to have at once a substance and a substantial form. ”

“ In all demonstrative sciences the rules are certain and infallible; but when we apply them, our fallible said uncertain faculties are very apt to depart from them, and fall into error. We must, therefore, in every reasoning form a new judgment, as a check or controul on our first judgment or belief; and must enlarge our view to comprehend a kind of history of all the instances, wherein our understanding has deceiv’d us, compar’d with those, wherein its testimony was just and true. Our reason must be considered as a kind of cause, of which truth is the natural effect ”

“ And indeed, if we consider the matter aright, ‘tis scarce possible it shou’d be otherwise, nor is it conceivable that our senses shou’d be more capable of deceiving us in the situation and relations, than in the nature of our impressions. For since all actions and sensations of the mind are known to us by consciousness, they must necessarily appear in every particular what they are, and be what they appear. Every thing that enters the mind, being in reality a perception, ‘tis impossible any thing shou’d to feeling appear different. ”

“ For ‘tis a quality, which I shall often have occasion to remark in human nature, and shall explain more fully in its proper place, that when objects are united by any relation, we have a strong propensity to add some new relation to them, in order to compleat the union. In our arrangement of bodies we never fail to place such as are resembling, in contiguity to each other, or at least in correspondent points of view: Why? but because we feel a satisfaction in joining the relation of contiguity to that of resemblance, or the resemblance of situation to that of qualities. ”