 File 17 of a Treatise of Human Nature by David Hume, Volume 1. This LibriVox recording is in the public domain. Recording by George Yeager, Book 1, Part 3, Section 2, of probability and of the idea of cause and effect. This is all I think necessary to observe concerning those four relations which are the foundation of science. But as to the other three, which depend not upon the idea, and may be absent or present even while that remains the same, it will be proper to explain them more particularly. These three relations are identity, the situations in time and place, and causation. All kinds of reasoning consist in nothing but a comparison and the discovery of those relations either constant or inconstant, which two or more objects bear to each other. This comparison we may make either when both the objects are present to the senses or when neither of them is present or when only one. When both the objects are present to the senses, along with the relation, we call this perception rather than reasoning, nor is there in this case any exercise of the thought or any action properly speaking but a mere passive admission of the impressions through the organs of sensation. According to this way of thinking, we ought not to receive as reasoning any of the observations we may make concerning identity and the relations of time and place, since in none of them the mind can go beyond what is immediately present to the senses, either to discover the real existence or the relations of objects. It is only causation which produces such a connection as to give us assurance from the existence or action of one object that it was followed or preceded by any other existence or action, nor can the other two relations be ever made use of in reasoning except so far as they either affect or are affected by it. There is nothing in any objects to persuade us that they are either always remote or always contiguous and when from experience and observation we discover that their relation in this particular is invariable, we always conclude there is some secret cause which separates or unites them. The same reasoning extends to identity. We readily suppose an object may continue individually the same, though several times absent from and present to the senses, and describe to it an identity notwithstanding the interruption of the perception whenever we conclude that if we had kept our eye or hand constantly upon it, it would have conveyed an invariable and uninterrupted perception. But this conclusion beyond the impressions of our senses can be founded only on the connection of cause and effect, nor can we otherwise have any security that the object is not changed upon us however much the new object may resemble that which was formally present to the senses. Whenever we discover such a perfect resemblance, we consider whether it be common in that species of objects, whether possibly or probably any cause could operate in producing the change and resemblance, and according as we determine concerning these causes and effects, we form our judgment concerning the identity of the object. Here then it appears that of those three relations which depend not upon the mere ideas, the only one that can be traced beyond our senses and informs us of existences and objects which we do not see or feel is causation. This relation therefore we shall endeavor to explain fully before we leave the subject of the understanding. To begin regularly we must consider the idea of causation and see from what origin it is derived. It is impossible to reason justly without understanding perfectly the idea concerning which we reason, and it is impossible perfectly to understand any idea without tracing it up to its origin and examining that primary impression from which it arises. The examination of the impression bestows a clearness on the idea, and the examination of the idea bestows a like clearness on all our reasoning. Let us therefore cast our eye on any two objects which we call cause and effect, and turn them on all sides in order to find that impression which produces an idea of such prodigious consequence. At first sight I perceive that I must not search for it in any of the particular qualities of the objects since whichever of these qualities I pitch on I find some object that is not possessed of it and yet falls under the denomination of cause or effect. And indeed there is nothing existent, either externally or internally, which is not to be considered either as a cause or an effect, though it is plain. There is no one quality which universally belongs to all beings and gives them a title to that denomination. The idea then of causation must be derived from some relation among objects, and that relation we must now endeavor to discover. I find in the first place that whatever objects are considered as causes or effects are contiguous, and that nothing can operate in a time or place which is ever so little removed from those of its existence. Though distant objects may sometimes seem productive of each other, they are commonly found upon examination to be linked by a chain of causes which are contiguous among themselves and to the distant objects. And when in any particular instance we cannot discover this connection, we still presume it to exist. We may therefore consider the relation of contiguity as essential to that of causation. At least may suppose it such, according to the general opinion, till we can find Amor Part 4, Section 5, proper occasion to clear up this matter by examining what objects are or are not susceptible of juxtaposition and conjunction. The second relation I shall observe as essential to causes and effects is not so universally acknowledged, but is liable to some controversy. It is that of priority of time in the cause before the effect. Some pretend that it is not absolutely necessary a cause should precede its effect, but that any object or action in the very first moment of its existence may exert its productive quality and give rise to another object or action perfectly co-temporary with itself. But beside that experience in most instances seems to contradict this opinion, we may establish the relation of priority by a kind of inference or reasoning. It is an established maxim, both in natural and moral philosophy, that an object which exists for any time in its full perfection, without producing another, is not its sole cause, but is assisted by some other principle which pushes it from its state of inactivity and makes it exert that energy of which it was secretly possessed. Now, if any cause may be perfectly co-temporary with its effect, it is certain, according to this maxim, that they must all of them be so, since any one of them which retards its operation for a single moment exerts not itself at that very individual time in which it might have operated, and therefore is no proper cause. The consequence of this would be no less than the destruction of that succession of causes which we observe in the world, and indeed the utter annihilation of time. For if one cause were co-temporary with its effect, and this effect with its effect, and so on, it is plain there would be no such thing as succession, and all objects must be co-existent. If this argument appears satisfactory, it is well. If not, I beg the reader to allow me the same liberty which I have used in the preceding case of supposing it such, for he shall find that the affair is of no great importance. Having thus discovered or supposed the two relations of contiguity and succession to be essential to causes and effects, I find I am stopped short, and can proceed no further in considering any single instance of cause and effect. Motion in one body is regarded upon impulse as the cause of motion in another. When we consider these objects with utmost attention, we find only that the one body approaches the other, and that the motion of it precedes that of the other, but without any sensible interval. It is in vain to rack ourselves with further thought and reflection upon this subject. We can go no farther in considering this particular instance. Should any one leave this instance and pretend to define a cause by saying it is something productive of another, it is evident he would say nothing, for what does he mean by production? Can he give any definition of it that will not be the same with that of causation? If he can, I desire it may be produced. If he cannot, he here runs in a circle and gives a synonymous term instead of a definition. Shall we then rest contented with these two relations of contiguity and succession as affording a complete idea of causation by no means? An object may be contiguous and prior to another without being considered as its cause. There is a necessary connection to be taken into consideration, and that relation is of much greater importance than any of the other two above mentioned. Here again I turn the object on all sides in order to discover the nature of this necessary connection and find the impression or impressions from which its idea may be derived. When I cast my eye on the known qualities of objects, I immediately discover that the relation of cause and effect depends not in the least on them. When I consider their relations, I can find none but those of contiguity and succession which I have already regarded as imperfect and unsatisfactory. Shall the despair of success make me assert that I am here possessed of an idea which is not preceded by any similar impression? This would be too strong a proof of levity and inconstancy, since the contrary principle has been already so firmly established as to admit of no further doubt, at least till we have more fully examined the present difficulty. We must therefore proceed like those who being in search of anything that lies concealed from them and not finding it in the place they expected, beat about all the neighboring fields without any certain view or design in hopes their good fortune will at last guide them to what they search for. It is necessary for us to leave the direct survey of this question concerning the nature of that necessary connection which enters into our idea of cause and effect and endeavor to find some other questions, the examination of which will perhaps afford a hint that may serve to clear up the present difficulty. Of these questions there occur two which I shall proceed to examine. That is, first, for what reason we pronounce it necessary that everything whose existence has a beginning should also have a cause? Secondly, why we conclude that such particular causes must necessarily have such particular effects and what is the nature of that inference we draw from the one to the other and of the belief we repose in it? I shall only observe, before I proceed any farther, that though the ideas of cause and effect be derived from the impressions of reflection as well as from those of sensation yet for brevity's sake, I commonly mention only the latter as the origin of these ideas, though I desire that whatever I say of them may also extend to the former. Passions are connected with their objects and with one another no less than external bodies are connected together. The same relation then of cause and effect which belongs to one must be common to all of them. End of File 17 File 18 of a Treatise of Human Nature by David Hume Volume 1 This LibriVox recording is in the public domain. Recording by George Yeager Book 1 Part 3 Section 3 Why is a cause always necessary? To begin with the first question concerning the necessity of a cause, it is a general maxim in philosophy that whatever begins to exist must have a cause of existence. This is commonly taken for granted in all reasonings without any proof given or demanded. It is supposed to be founded on intuition and to be one of those maxims which though they may be denied with lips, it is impossible for men in their hearts really to doubt of. But if we examine this maxim by the idea of knowledge above explained, we shall discover in it no mark of any such intuitive certainty, but on the contrary shall find that it is of a nature quite foreign to that species of conviction. All certainty arises from the comparison of ideas and from the discovery of such relations as are unalterable so long as the ideas continue the same. These relations are resemblance, proportions in quantity and number, degrees of inequality and contrarity, none of which are implied in this proposition. Whatever has a beginning has also a cause of existence. That proposition, therefore, is not intuitively certain. At least anyone who would assert it to be intuitively certain must deny these to be the only infallible relations and must find some other relation of that kind to be implied in it, which it will then be time enough to examine. But here is an argument which proves at once that the foregoing proposition is neither intuitively nor demonstrably certain. We can never demonstrate the necessity of a cause to every new existence or new modification of existence without shooing at the same time the impossibility there is that anything can ever begin to exist without some productive principle. And where the latter proposition cannot be proved, we must despair of ever being able to prove the former. Now that the latter proposition is utterly incapable of a demonstrative proof, we may satisfy ourselves by considering that as all distinct ideas are separable from each other and as the ideas of cause and effect are evidently distinct, it will be easy for us to conceive any object to be nonexistent this moment and existent the next, without conjoining to it the distinct idea of a cause or productive principle. The separation, therefore, of the idea of a cause from that of a beginning of existence is plainly possible for the imagination, and consequently the actual separation of these objects is so far possible that it implies no contradiction nor absurdity, and is therefore incapable of being refuted by any reasoning from mere ideas without which it is impossible to demonstrate the necessity of a cause. Accordingly, we shall find upon examination that every demonstration which has been produced for the necessity of a cause is fallacious and sophisticated. All the points of time and place, say some philosophers, Mr. Hobbes, in which we can suppose any object to begin to exist are in themselves equal, and unless there be some cause which is peculiar to one time and to one place, and which by that means determines and fixes the existence, it must remain in eternal suspense, and the object can never begin to be for want of something to fix its beginning. But I ask, is there any more difficulty in supposing the time and place to be fixed without a cause than to suppose the existence to be determined in that manner? The first question that occurs on this subject is always whether the object shall exist or not, the next when and where it shall begin to exist. If the removal of a cause be intuitively absurd in the one case, it must be so in the other, and if that absurdity be not clear without a proof in the one case, it will equally require one in the other. The absurdity, then, of the one supposition can never be a proof of that of the other, since they are both upon the same footing and must stand or fall by the same reasoning. The second argument, Dr. Clark and others, which I find used on this head, labors under unequal difficulty. Everything it is said must have a cause, for if anything wanted a cause, it would produce itself, that is, exist before it existed, which is impossible. But this reasoning is plainly inconclusive, because it supposes that in our denial of a cause, we still grant what we expressly deny. That is, that there must be a cause which therefore is taken to be the object itself, and that, no doubt, is an evident contradiction. But to say that anything is produced or to express myself more properly comes into existence without a cause is not to affirm that it is itself its own cause, but on the contrary, in excluding all external causes, excludes a fortiori, the thing itself which is created. An object that exists absolutely without any cause certainly is not its own cause, and when you assert that the one follows from the other, you suppose the very point in question, and take it for granted that it is utterly impossible anything can ever begin to exist without a cause, but that upon the exclusion of one productive principle, we must still have recourse to another. It is exactly the same case with the third argument, Mr. Locke, which has been employed to demonstrate the necessity of a cause. Whatever is produced without any cause is produced by nothing, or in other words, has nothing for its cause, but nothing can never be a cause no more than it can be something or equal to two right angles. By the same intuition that we perceive nothing not to be equal to two right angles, or not to be something, we perceive that it can never be a cause, and consequently must perceive that every object has a real cause of its existence. I believe it will not be necessary to employ many words ensuring the weakness of this argument after what I have said of the foregoing. They are all of them founded on the same fallacy, and are derived from the same turn of thought. It is sufficient only to observe that when we exclude all causes, we really do exclude them, and neither suppose nothing nor the object itself to be the causes of the existence, and consequently can draw no argument from the absurdity of these suppositions to prove the absurdity of that exclusion. If everything must have a cause, it follows that upon the exclusion of other causes we must accept of the object itself or of nothing as causes. But it is the very point in question whether everything must have a cause or not, and therefore, according to all just reasoning, it ought never to be taken for granted. They are still more frivolous who say that every effect must have a cause because it is implied in the very idea of effect. Every effect necessarily presupposes a cause, effect being a relative term of which cause is the correlative. But this does not prove that every being must be preceded by a cause, no more than it follows because every husband must have a wife, that therefore every man must be married. The true state of the question is whether every object which begins to exist must owe its existence to a cause, and this I assert neither to be intuitively nor demonstratively certain, and hope to have proved it sufficiently by the foregoing arguments. Since it is not from knowledge or any scientific reasoning that we derive the opinion of the necessity of a cause to every new production, that opinion must necessarily arise from observation and experience. The next question then should naturally be how experience gives rise to such a principle. But as I find it will be more convenient to sink this question in the following. Why we conclude that such particular causes must necessarily have such particular effects, and why we form an inference from one to the other. We shall make that the subject of our future inquiry. It will perhaps be found in the end that the same answer will serve for both questions. End of File 18. File 19 of a Treatise of Human Nature by David Hume, Volume 1. This LibriVox recording is in the public domain. Recording by George Yeager. Book 1, Part 3, Section 4 of the component parts of our reasonings concerning causes and effects. Though the mind in its reasonings from causes or effects carries its view beyond those objects which it sees or remembers, it must never lose sight of them entirely, nor reason merely upon its own ideas without some mixture of impressions or at least of ideas of the memory which are equivalent to impressions. When we infer effects from causes, we must establish the existence of these causes, which we have only two ways of doing, either by an immediate perception of our memory or senses, or by an inference from other causes, which causes, again, we must ascertain in the same manner, either by a present impression, or by an inference from their causes, and so on, till we arrive at some object which we see or remember. It is impossible for us to carry on our inferences in infinitum, and the only thing that can stop them is an impression of the memory or senses beyond which there is no room for doubt or inquiry. To give an instance of this, we may choose any point of history and consider for what reason we either believe or reject it. Thus, we believe that Caesar was killed in the Senate House on the Ides of March, and that because this fact is established on the unanimous testimony of historians who agree to assign this precise time and place to that event. Here are certain characters and letters present, either to our memory or senses, which characters we likewise remember to have been used as the signs of certain ideas. And these ideas were either in the minds of such as were immediately present at that action and received the ideas directly from its existence, or they were derived from the testimony of others. And that, again, from another testimony by a visible gradation, till we arrive at those who were eyewitnesses and spectators of the event. It is obvious all this chain of argument or connection of causes and defects is at first founded on those characters or letters which are seen or remembered, and that without the authority either of the memory or senses, our whole reasoning would be numerical and without foundation. Every link of the chain would in that case hang upon another. But there would not be anything fixed to one end of it capable of sustaining the whole. And consequently, there would be no belief nor evidence. And this actually is the case with all hypothetical arguments or reasonings upon a supposition. There being in them neither any present impression nor belief of a real existence. I need not observe that it is no just objection to the present doctrine that we can reason upon our past conclusions or principles without having recourse to those impressions from which they first arose. For even supposing these impressions should be entirely effaced from the memory, the conviction they produced may still remain. And it is equally true that all reasonings concerning causes and defects are originally derived from some impression in the same manner as the assurance of a demonstration proceeds always from a comparison of ideas, though it may continue after the comparison is forgotten. End of file 19. File 20 of a Treatise of Human Nature by David Hume. Volume one. This LibriVox recording is in the public domain. Recording by George Yeager. Book one, part three, section five, of the impressions of the senses and memory. In this kind of reasoning, then, from causation, we employ materials which are of a mixed and heterogeneous nature and which, however connected, are yet essentially different from each other. All our arguments concerning causes and defects consist both of an impression of the memory or senses and of the idea of that existence which produces the object of the impression or is produced by it. Here, therefore, we have three things to explain. That is, first, the original impression. Secondly, the transition to the idea of the connected cause or effect. Thirdly, the nature and qualities of that idea. As to those impressions which arise from the senses, their ultimate cause is, in my opinion, perfectly inexplicable by human reason. And it will always be impossible to decide with certainty whether they arise immediately from the object or are produced by the creative power of the mind or are derived from the author of our being. Nor is such a question anyway material to our present purpose. We may draw inferences from the coherence of our perceptions, whether they be true or false, whether they represent nature justly or be mere illusions of the senses. When we search for the characteristic which distinguishes the memory from the imagination, we must immediately perceive that it cannot lie in the simple ideas it presents to us since both these faculties borrow their simple ideas from the impressions and can never go beyond these original perceptions. These faculties are as little distinguished from each other by the arrangement of their complex ideas. For though it be a peculiar property of the memory to preserve the original order and position of its ideas, while the imagination transposes and changes them as it pleases, yet this difference is not sufficient to distinguish them in their operation or make us know the one from the other. It being impossible to recall the past impressions in order to compare them with our present ideas and see whether their arrangement be exactly similar. Since therefore the memory is known neither by the order of its complex ideas nor the nature of its simple ones, it follows that the difference betwixt it and the imagination lies in its superior force and vivacity. A man may indulge his fancy in feigning any past scene of adventures, nor would there be any possibility of distinguishing this from a remembrance of a like kind were not the ideas of the imagination, fainter and more obscure. It frequently happens that when two men have been engaged in any scene of action, the one shall remember it much better than the other and shall have all the difficulty in the world to make his companion recollect it. He runs over several circumstances in vain, mentions the time, the place, the company, what was said, what was done on all sides, till at last he hits on some lucky circumstance that revives the whole and gives his friend a perfect memory of everything. Here the person that forgets receives at first all the ideas from the discourse of the other with the same circumstances of time and place, though he considers them as mere fictions of the imagination. But as soon as the circumstance is mentioned that touches the memory, the very same ideas now appear in a new light and have in a manner a different feeling from what they had before. Without any other alteration beside that of the feeling, they become immediately ideas of the memory and are assented to. Since therefore the imagination can represent all the same objects that the memory can offer to us. And since those faculties are only distinguished by the different feeling of the ideas they present, it may be proper to consider what is the nature of that feeling. And here I believe everyone will readily agree with me that the ideas of the memory are more strong and lively than those of the fancy. A painter who intended to represent a passion or emotion of any kind would endeavor to get a sight of a person actuated by a like emotion in order to enliven his ideas and give them a force and vivacity superior to what is found in those which are mere fictions of the imagination. The more recent this memory is, the clearer is the idea. And when after a long interval he would return to the contemplation of his object, he always finds its idea to be much decayed, if not wholly obliterated. We are frequently in doubt concerning the ideas of the memory as they become very weak and feeble and are at a loss to determine whether any image proceeds from the fancy or the memory when it is not drawn in such lively colors as distinguish that latter faculty. I think I remember such an event, says one, but I'm not sure. A long tract of time has almost worn it out of my memory and leaves me uncertain whether or not it be the pure offspring of my fancy. And as an idea of the memory by losing its force and vivacity may degenerate to such a degree as to be taken for an idea of the imagination, so on the other hand, an idea of the imagination may acquire such a force and vivacity as to pass for an idea of the memory and counterfeit its effects on the belief and judgment. This is noted in the case of Liars, who by the frequent repetition of their lies come at last to believe and remember them as realities, custom and habit having in this case, as in many others, the same influence on the mind as nature and in fixing the idea with equal force and vigor. Thus it appears that the belief or assent which always attends the memory and senses is nothing but the vivacity of those perceptions they present and that this alone distinguishes them from the imagination. To believe is in this case to feel an immediate impression of the senses or a repetition of that impression in the memory. It is merely the force and liveliness of the perception which constitutes the first act of the judgment and lays the foundation of that reasoning which we build upon it when we trace the relation of cause and effect. End of file 20. File 21 of a Treatise of Human Nature by David Hume, volume one. This LibriVox recording is in the public domain, recording by George Yeager. Book one, part three, section six of the inference from the impression to the idea. It is easy to observe that in tracing this relation, the inference we draw from cause to effect is not derived merely from a survey of these particular objects and from such a penetration into their essences as may discover the dependence of the one upon the other. There is no object which implies the existence of any other if we consider these objects in themselves and never look beyond the ideas which we form of them. Such an inference would amount to knowledge and would imply the absolute contradiction and impossibility of conceiving anything different. But as all distinct ideas are separable, it is evident there can be no impossibility of that kind. When we pass from a present impression to the idea of any object, we might possibly have separated the idea from the impression and have substituted any other idea in its room. It is therefore by experience only that we can infer the existence of one object from that of another. The nature of experience is this. We remember to have had frequent instances of the existence of one species of objects and also remember that the individuals of another species of objects have always attended them and have existed in a regular order of contiguity and succession with regard to them. Thus, we remember to have seen that species of object we call flame and to have felt that species of sensation we call heat. We likewise call to mind their constant conjunction in all past instances. Without any further ceremony, we call the one cause and the other effect and infer the existence of the one from that of the other. In all those instances from which we learn the conjunction of particular causes and effects, both the causes and effects have been perceived by the senses and are remembered. But in all cases wherein we reason concerning them, there is only one perceived or remembered and the other is supplied in conformity to our past experience. Thus, in advancing, we have insensibly discovered a new relation between cause and effect when we least expected it and were entirely employed upon another subject. This relation is their constant conjunction. Contiguity and succession are not sufficient to make us pronounce any two objects to be cause and effect unless we perceive that these two relations are preserved in several instances. We may now see the advantage of quitting the direct survey of this relation in order to discover the nature of that necessary connection which makes so essential a part of it. There are hopes that by this means we may at last arrive at our proposed end. Though to tell the truth, this new discovered relation of a constant conjunction seems to advance us but very little in our way. For it implies no more than this, that like objects have always been placed in like relations of contiguity and succession. And it seems evident, at least at first sight, that by this means we can never discover any new idea and can only multiply but not enlarge the objects of our mind. It may be thought that what we learn not from one object, we can never learn from a hundred, which are all of the same kind and are perfectly resembling in every circumstance. As our senses shoe us in one instance to bodies or emotions or qualities in certain relations of success and contiguity, so our memory presents us only with a multitude of instances wherein we always find like bodies, motions or qualities in like relations. From the mere repetition of any past impression, even to infinity, there never will arise any new original idea such as that of a necessary connection. And the number of impressions has in this case no more effect than if we can find ourselves to one only. But though this reasoning seems just and obvious, yet as it would be folly to despair too soon, we shall continue the thread of our discourse. And having found that after the discovery of the constant conjunction of any objects, we always draw an inference from one object to another, we shall now examine the nature of that inference and of the transition from the impression to the idea. Perhaps it will appear in the end that the necessary connection depends on the inference instead of the inferences depending on the necessary connection. Since it appears that the transition from an impression present to the memory or senses to the idea of an object which we call cause or effect is founded on past experience and on our remembrance of their constant conjunction, the next question is whether experience produces the idea by means of the understanding or imagination, whether we are determined by reason to make the transition or by a certain association and relation of perceptions. If reason determined thus, it would proceed upon that principle that instances of which we have had no experience must resemble those of which we have had experience and that the course of nature continues always uniformly the same. In order therefore to clear up this matter, let us consider all the arguments upon which such a proposition may be supposed to be founded. And as these must be derived either from knowledge or probability, let us cast our eye on each of these degrees of evidence and see whether they afford any just conclusion of this nature. Our foregoing method of reasoning will easily convince us that there can be no demonstrative arguments to prove that those instances of which we have had no experience resemble those of which we have had experience. We can at least conceive a change in the course of nature which sufficiently proves that such a change is not absolutely impossible. To form a clear idea of anything is an undeniable argument for its possibility and is alone a refutation of any pretended demonstration against it. Probability as it discovers not the relations of ideas considered as such, but only those of objects must in some respects be founded on the impressions of our memory and senses and in some respects on our ideas. Were there no mixture of any impression in our probable reasonings, the conclusion would be entirely comirical. And were there no mixture of ideas, the action of the mind in observing the relation would, properly speaking, be sensation, not reasoning. It is therefore necessary that in all probable reasonings there be something present to the mind, either seen or remembered, and that from this we infer something connected with it, which is not seen nor remembered. The only connection or relation of objects which can lead us beyond the immediate impressions of our memory and senses is that of cause and effect. And that because it is the only one on which we can found a just inference from one object to another. The idea of cause and effect is derived from experience, which informs us that such particular objects in all past instances have been constantly conjoined with each other. And as an object similar to one of these is supposed to be immediately present in its impression, we thence presume on the existence of one similar to its usual attendant. According to this account of things, which is, I think, in every point unquestionable, probability is founded on the presumption of a resemblance betwixt those objects of which we have had experience and those of which we have had none. And therefore it is impossible this presumption can arise from probability. The same principle cannot be both the cause and effect of another. And this is, perhaps, the only proposition concerning that relation, which is either intuitively or demonstratively certain. Should anyone think to elude this argument and without determining whether our reasoning on this subject be derived from demonstration or probability, pretend that all conclusions from causes and effects are built on solid reasoning, I can only desire that this reasoning may be produced in order to be exposed to our examination. It may, perhaps, be said that after experience of the constant conjunction of certain objects, we reason in the following manner. Such an object is always found to produce another. It is impossible it could have this effect if it was not endowed with a power of production. The power necessarily implies the effect. And therefore, there is a just foundation for drawing a conclusion from the existence of one object to that of its usual attendant. The past production implies a power. The power implies a new production. And the new production is what we infer from the power and the past production. It were easy for me to shoo the weakness of this reasoning where I willing to make use of those observations I have already made that the idea of production is the same with that of causation and that no existence certainly and demonstratively implies a power in any other object or were it proper to anticipate what I shall have occasion to remark afterwards concerning the idea we form of power and efficacy. But as such a method of proceeding may seem either to weaken my system by resting one part of it on another or to breed a confusion in my reasoning, I shall endeavor to maintain my present assertion without any such assistance. It shall therefore be allowed for a moment that the production of one object by another in any one instance implies a power and that this power is connected with its effect. But it having been already proved that the power lies not in the sensible qualities of the cause and there being nothing but the sensible qualities present to us, I asked why in other instances you presume that the same power still exists merely upon the appearance of these qualities. Your appeal to past experience decides nothing in the present case and at the utmost can only prove that that very object which produced any other was at that very instant endowed with such a power but can never prove that the same power must continue in the same object or collection of sensible qualities much less that a like power is always conjoined with like sensible qualities. Should it be said that we have experienced that the same power continues united with the same object and that like objects are endowed with like powers, I would renew my question. Why from this experience we form any conclusion beyond those past instances of which we have had experience? If you answer this question in the same manner as the preceding, your answer gives still occasion to a new question of the same kind. Even in infinitum which clearly proves that the foregoing reasoning had no just foundation. Thus not only our reason fails us in the discovery of the ultimate connection of causes and effects but even after experience has informed us of their constant conjunction, it is impossible for us to satisfy ourselves by our reason why we should extend that experience beyond those particular instances which have fallen under our observation. We suppose but are never able to prove that there must be a resemblance betwixt those objects of which we have had experience and those which lie beyond the reach of our discovery. We have already taken notice of certain relations which make us pass from one object to another even though there be no reason to determine us to that transition. And this we may establish for a general rule that wherever the mind constantly and uniformly makes a transition without any reason, it is influenced by these relations. Now this is exactly the present case. Reason can never shoo us the connection of one object with another, though aided by experience and the observation of their constant conjunction in all past instances. When the mind therefore passes from the idea or impression of one object to the idea or belief of another, it is not determined by reason but by certain principles which associate together the ideas of these objects and unite them in the imagination. Had ideas no more union in the fancy than objects seem to have to the understanding, we could never draw any inference from causes to effects nor repose belief in any matter of fact. The inference therefore depends solely on the union of ideas. The principles of union among ideas I have reduced to three general ones and have asserted that the idea or impression of any object naturally introduces the idea of any other object that is resembling, contiguous to, or connected with it. These principles I allow to be neither the infallible nor the sole causes of an union among ideas. They are not the infallible causes for one may fix his attention during some time on any one object without looking farther. They are not the sole causes for the thought has evidently a very irregular motion in running along its objects and may leap from the heavens to the earth from one end of the creation to the other without any certain method or order. But though I allow this weakness in these three relations and this irregularity in the imagination, yet I assert that the only general principles which associate ideas are resemblance, contiguity, and causation. There is indeed a principle of union among ideas which at first sight may be esteemed different from any of these, but will be found at the bottom to depend on the same origin. When every individual of any species of objects is found by experience to be constantly united with an individual of another species, the appearance of any new individual of either species naturally conveys the thought to its usual attendant. Thus, because such a particular idea is commonly annexed to such a particular word, nothing is required but the hearing of that word to produce the correspondent idea. And it will scarce be possible for the mind by its utmost efforts to prevent that transition. In this case, it is not absolutely necessary that upon hearing such a particular sound, we should reflect on any past experience and consider what idea has been usually connected with the sound. The imagination of itself supplies the place of this reflection and is so accustomed to pass from the word to the idea that it interposes not a moment's delay betwixt the hearing of the one and the conception of the other. But though I acknowledge this to be a true principle of association among ideas, I assert it to be the very same with that betwixt the ideas of cause and effects and to be an essential part in all our reasonings from that relation. We have no other notion of cause and effect but that of certain objects which have been always conjoined together and which in all past instances have been found inseparable. We cannot penetrate into the reason of the conjunction. We only observe the thing itself and always find that from the constant conjunction the objects acquire and union in the imagination. When the impression of one becomes present to us, we immediately form an idea of its usual attendant and consequently we may establish this as one part of the definition of an opinion or belief that it is an idea related to or associated with a present impression. Thus, though causation be a philosophical relation as implying contiguity, succession and constant conjunction, yet it is only so far as it is a natural relation and produces an union among our ideas that we are able to reason upon it or draw any inference from it. End of file 21. File 22 of a Treatise of Human Nature by David Hume, volume one. This LibriVox recording is in the public domain. Recording by George Yeager. Book one, part three, section seven of the nature of the idea or belief. The idea of an object is an essential part of the belief of it but not the whole. We conceive many things which we do not believe. In order then to discover more fully the nature of belief or the qualities of those ideas we assent to, let us weigh the following considerations. It is evident that all reasonings from causes or effects terminate in conclusions concerning matter of fact. That is concerning the existence of objects or of their qualities. It is also evident that the idea of existence is nothing different from the idea of any object and that when after the simple conception of anything we would conceive it as existent, we in reality make no addition to or alteration on our first idea. Thus when we affirm that God is existent, we simply form the idea of such a being as he is represented to us, nor is the existence which we attribute to him conceived by a particular idea which we join to the idea of his other qualities and can again separate and distinguish from them. But I go farther and not content with asserting that the conception of the existence of any object is no addition to the simple conception of it. I likewise maintain that the belief of the existence joins no new ideas to those which compose the idea of the object. When I think of God, when I think of him as existent and when I believe him to be existent, my idea of him neither increases nor diminishes. But as it is certain, there is a great difference betwixt the simple conception of the existence of an object and the belief of it. And as this difference lies not in the parts or composition of the idea which we conceive, it follows that it must lie in the manner in which we conceive it. Suppose a person present with me who advances propositions to which I do not assent, that Caesar died in his bed, that silver is more fusible than lead, or mercury heavier than gold. It is evident that notwithstanding my incredulity, I clearly understand his meaning and form all the same ideas which he forms. My imagination is endowed with the same powers as his, nor is it possible for him to conceive any idea which I cannot conceive, nor conjoin any which I cannot conjoin. I therefore ask, wherein consists the difference betwixt believing and disbelieving any proposition? The answer is easy with regard to propositions that are proved by intuition or demonstration. In that case, the person who assents not only conceives the ideas according to the proposition, but is necessarily determined to conceive them in that particular manner either immediately or by the interposition of other ideas. Whatever is absurd is unintelligible, nor is it possible for the imagination to conceive anything contrary to a demonstration. But as in reasonings from causation and concerning matters of fact, this absolute necessity cannot take place and the imagination is free to conceive both sides of the question. I still ask, wherein consists the difference betwixt incredulity and belief? Since in both cases the conception of the idea is equally possible and requisite, it will not be a satisfactory answer to say that a person who does not assent to a proposition you advance after having conceived the object in the same manner with you, immediately conceives it in a different manner and has different ideas of it. This answer is unsatisfactory, not because it contains any falsehood, but because it discovers not all the truth. It is confessed that in all cases wherein we dissent from any person, we conceive both sides of the question, but as we can believe only one, it evidently follows that the belief must make some difference betwixt that conception to which we assent and that from which we dissent. We may mingle and unite and separate and confound and vary our ideas in a hundred different ways, but until there appears some principle which fixes one of these different situations, we have in reality no opinion. And this principle as it plainly makes no addition to our precedent ideas can only change the manner of our conceiving them. All the perceptions of the mind are of two kinds. That is impressions and ideas which differ from each other only in their different degrees of force and vivacity. Our ideas are copied from our impressions and represent them in all their parts. When you would anyway vary the idea of a particular object, you can only increase or diminish its force and vivacity. If you make any other change on it, it represents a different object or impression. The case is the same as in colors. A particular shade of any color may acquire a new degree of liveliness or brightness without any other variation. But when you produce any other variation, it is no longer the same shade or color. So that as belief does nothing but vary the manner in which we conceive any object, it can only bestow on our ideas an additional force and vivacity. An opinion therefore or belief may be most accurately defined, a lively idea related to or associated with a present impression. We may here take occasion to observe a very remarkable error which being frequently inculcated in the schools has become a kind of established maxim and is universally received by all logicians. This error consists in the vulgar division of the acts of the understanding into conception, judgment, and reasoning, and in the definitions we give of them. Conception is defined to be the simple survey of one or more ideas. Judgment to be the separating or uniting of different ideas. Reasoning to be the separating or uniting of different ideas by the interposition of others which show the relation they bear to each other. But these distinctions and definitions are faulty in very considerable articles. For first, it is far from being true that in every judgment which we form we unite two different ideas. Since in that proposition God is or indeed any other which regards existence, the idea of existence is no distinct idea which we unite with that of the object and which is capable of forming a compound idea by the union. Secondly, as we can thus form a proposition which contains only one idea so we may exert our reason without employing more than two ideas and without having recourse to a third to serve as a medium betwixt them. We infer a cause immediately from its effect and this inference is not only a true species of reasoning but the strongest of all others and more convincing than when we interpose another idea to connect the two extremes. What we may in general affirm concerning these three acts of the understanding is that taking them in a proper light they all resolve themselves into the first and are nothing but particular ways of conceiving our objects. Whether we consider a single object or several whether we dwell on these objects or run from them to others and in whatever form or order we survey them the act of the mind exceeds not a simple conception and the only remarkable difference which occurs on this occasion is when we join belief to the conception and are persuaded of the truth of what we conceive. This act of the mind has never yet been explained by any philosopher and therefore I am at liberty to propose my hypothesis concerning it which is that it is only a strong and steady conception of any idea and such as approaches in some measure to an immediate impression. Footnote five. Here are the heads of those arguments which lead us to this conclusion. When we infer the existence of an object from that of others some object must always be present either to the memory or senses in order to be the foundation of our reasoning since the mind cannot run up with its inferences in infinitum. Reason can never satisfy us that the existence of any one object does ever imply that of another so that when we pass from the impression of one to the idea or belief of another we are not determined by reason but by custom or a principle of association. But belief is somewhat more than a simple idea. It is a particular manner of forming an idea and as the same idea can only be varied by a variation of its degrees of force and vivacity it follows upon the whole that belief is a lively idea produced by a relation to a present impression according to the foregoing definition. End of footnote five. This operation of the mind which forms the belief of any matter of fact seems hitherto to have been one of the greatest mysteries of philosophy though no one has so much as suspected that there was any difficulty in explaining it. For my part I must own that I find a considerable difficulty in the case and that even when I think I understand the subject perfectly I am at a loss for terms to express my meaning. I conclude by an induction which seems to me very evident that an opinion or belief is nothing but an idea that is different from a fiction not in the nature or the order of its parts but in the manner of its being conceived. But when I would explain this manner I scarce find any word that fully answers the case but am obliged to have recourse to everyone's feeling in order to give him a perfect notion of this operation of the mind. An idea assented to feels different from a fictitious idea that the fancy alone presents to us and this different feeling I endeavour to explain by calling it a superior force or a vivacity or solidity or firmness or steadiness. This variety of terms which may seem so unphilosophical is intended only to express that act of the mind which renders realities more present to us than fictions which causes them to weigh more in the thought and gives them a superior influence on the passions and imagination. Provided we agree about the thing it is needless to dispute about the terms. The imagination has the command over all its ideas and can join and mix and vary them in all the ways possible. It may conceive objects with all the circumstances of place and time. It may set them in a manner before our eyes in their true colors just as they might have existed. But as it is impossible that that faculty can ever of itself reach belief it is evident that belief consists not in the nature and order of our ideas but in the manner of their conception and in their feeling to the mind. I confess that it is impossible to explain perfectly this feeling or manner of conception. We may make use of words that express something near it but its true and proper name is belief which is a term that everyone sufficiently understands in common life and in philosophy we can go no farther than assert that it is something felt by the mind which distinguishes the ideas of the judgment from the fictions of the imagination. It gives them more force and influence makes them appear of greater importance infixes them in the mind and renders them the governing principles of all our actions. This definition will also be found to be entirely conformable to everyone's feeling and experience. Nothing is more evident than that those ideas to which we assent are more strong, firm and vivid than the loose reveries of a castle builder. If one person sits down to read a book as a romance and another as a true history they plainly receive the same ideas and in the same order nor does the incredulity of the one and the belief of the other hinder them from putting the very same sense upon their author. His words produce the same ideas in both though his testimony has not the same influence on them. The latter has a more lively conception of all the incidents. He enters deeper into the concerns of the persons, represents to himself their actions and characters and friendships and enmities. He even goes so far as to form a notion of their features and air and person. While the former who gives no credit to the testimony of the author has a more faint and languid conception of all these particulars and except on account of the style and ingenuity of the composition can receive little entertainment from it. End of File 22. File 23 of A Treatise of Human Nature by David Hume. Volume 1. This LibriVox recording is in the public domain. Recording by George Yeager. Book 1. Part 3. Section 8. Of the Causes of Belief. Having thus explained the nature of belief and shun that it consists in a lively idea related to a present impression, let us now proceed to examine from what principles it has derived and what bestows the vivacity on the idea. I would willingly establish it as a general maxim in the science of human nature that when any impression becomes present to us it not only transports the mind to such ideas as are related to it but likewise communicates to them a share of its force and vivacity. All the operations of the mind depend in a great measure on its disposition when it performs them and according as the spirits are more or less elevated and the attention more or less fixed the action will always have more or less vigor and vivacity. When therefore any object is presented which elevates and enlivens the thought every action to which the mind applies itself will be more strong and vivid as long as that disposition continues. Now it is evident the continuance of the disposition depends entirely on the objects about which the mind is employed and that any new object naturally gives a new direction to the spirits and changes the disposition as on the contrary when the mind fixes constantly on the same object or passes easily and insensibly along related objects the disposition has a much longer duration. Hence it happens that when the mind is once enlivened by a present impression it proceeds to form a more lively idea of the related objects by a natural transition of the disposition from the one to the other. The change of the objects is so easy that the mind is scarce sensible of it but applies itself to the conception of the related idea with all the force and vivacity it acquired from the present impression. If in considering the nature of relation and that facility of transition which is essential to it we can satisfy ourselves concerning the reality of this phenomenon it is well. But I must confess I place my chief confidence in experience to prove so material a principle. We may therefore observe as the first experiment to our present purpose that upon the appearance of the picture of an absent friend our idea of him is evidently enlivened by the resemblance and that every passion which that idea occasions whether of joy or sorrow acquires new force and vigor. In producing this effect there concur both a relation and a present impression. Where the picture bears him no resemblance or at least was not intended for him it never so much as conveys our thought to him and where it is absent as well as the person though the mind may pass the thought of the one to that of the other it feels its idea to be rather weakened than enlivened by that transition. We take a pleasure in viewing the picture of a friend when it is set before us but when it is removed rather choose to consider him directly than by reflection in an image which is equally distant and obscure. The ceremonies of the Roman Catholic religion may be considered as experiments of the same nature. The devotees of that strange superstition usually plead an excuse of the memories with which they are up braided that they feel the good effect of those external motions and postures and actions in enlivening their devotion and quickening their fervor which otherwise would decay away if directed entirely to distant and immaterial objects. We shadow out the objects of our faith say they in sensible types and images and render them more present to us by the immediate presence of these types than it is possible for us to do merely by an intellectual view of contemplation. Sensible objects have always a greater influence on the fancy than any other and this influence they readily convey to those ideas to which they are related and which they resemble. I shall only infer from these practices and this reasoning that the effect of resemblance in enlivening the idea is very common. And as in every case a resemblance and a present impression must concur we are abundantly supplied with experiments to prove the reality of the foregoing principle. We may add force to these experiments by others of a different kind in considering the effects of contiguity as well as of resemblance. It is certain that distance diminishes the force of every idea and that upon our approach to any object though it does not discover itself to our senses it operates upon the mind with an influence that imitates an immediate impression. The thinking on any object readily transports the mind to what is contiguous only the actual presence of an object that transports it with a superior vivacity. When I am a few miles from home whatever relates to it touches me more nearly than when I am 200 leagues distant though even at that distance the reflecting on anything in the neighborhood of my friends and family naturally produces an idea of them. But as in this latter case both the objects of the mind are ideas not withstanding there is an easy transition betwixt them. That transition alone is not able to give a superior vivacity to any of the ideas for what of some immediate impression. Footnote 6 Reader's note the Latin quotation from Cicero Definebus book 5 is not read here because it is translated to English immediately following. End of footnote 6 Reader's note the text's translation of Cicero should I, he said, attribute to instinct or to some kind of delusion the fact that when we see those places in which we are told notable men spent much of their time we are more powerfully affected than when we hear of the exploits of the men themselves or read something written. This is just what is happening to me now for I am reminded of Plato who we are told was the first to take a practice of holding discussions here. Those gardens of his nearby do not merely put me in mind of him they seem to set the man himself before my very eyes. Speusipus was here, so was Xenocrates so was his pupil Palermo and that very seat which we may view was his. Then again when I looked at our Senate House the old building of Hostileus not this new one when it was enlarged it diminished in my estimation I used to think of Scipio, Cato, Leelius and in particular of my own grandfather such is the power of places to evoke associations so it is with good reason that they are used as a basis for memory training. Readers note and of the texts translation of Cicero No one can doubt but causation has the same influence as the other two relations of resemblance and contiguity. Superstitious people are fond of the relics of saints and holy men for the same reason that they seek after types and images in order to enliven their devotion and give them a more intimate and strong conception of those exemplary lives which they desire to imitate. Now it is evident one of the best relics a devotee could procure would be the handiwork of a saint and if his clothes and furniture are ever to be considered in this light it is because they were once at his disposal and were moved and defected by him in which respect they are to be considered as imperfect effects and as connected with him by a shorter chain of consequences than any of those from which we learn the reality of his existence. This phenomenon clearly proves that a present impression with a relation of causation may enliven any idea and consequently produce belief or assent according to the precedent definition of it. But why need we seek for other arguments to prove that a present impression with a relation or transition of the fancy may enliven any idea when this very instance of our reasonings from cause and effect will alone suffice to that purpose. It is certain we must have an idea of every matter of fact which we believe. It is certain that this idea arises only from a relation to a present impression. It is certain that the belief super adds nothing to the idea but only changes our manner of conceiving it and renders it more strong and lively. The present conclusion concerning the influence of relation is the immediate consequence of all these steps and every step appears to me sure and infallible. There enters nothing into this operation of the mind but a present impression, a lively idea and a relation or association in the fancy betwixt the impression and idea so that there can be no suspicion of mistake. In order to put this whole affair in a fuller light let us consider it as a question in natural philosophy which we must determine by experience and observation. I suppose there is an object presented from which I draw a certain conclusion and form to myself ideas which I am said to believe or assent to. Here it is evident that however that object which is present to my senses and that other whose existence I infer by reasoning may be thought to influence each other by their particular powers or qualities. Yet as the phenomenon of belief which we at present examine is merely internal these powers and qualities being entirely unknown can have no hand in producing it. It is the present impression which is to be considered as the true and real cause of the idea and of the belief which attends it. We must therefore endeavor to discover by experiments the particular qualities by which it is enabled to produce so extraordinary an effect. First then I observe that the present impression has not this effect by its own proper power and efficacy and when considered alone as a single perception limited to the present moment. I find that an impression from which on its first appearance I can draw no conclusion may afterwards become the foundation of belief when I have had experience of its usual consequences. We must in every case have observed the same impression in past instances and have found it to be constantly conjoined with some other impression. This is confirmed by such a multitude of experiments that it admits not of the smallest doubt. From a second observation I conclude that the belief which attends the present impression and is produced by a number of past impressions and conjunctions that this belief I say arises immediately without any new operation of the reason or imagination. Of this I can be certain because I never am conscious of any such operation and find nothing in the subject on which it can be founded. Now as we call everything custom which proceeds from a past repetition without any new reasoning or conclusion we may establish it as a certain truth that all the belief which follows upon any present impression is derived solely from that origin. When we are accustomed to see two impressions conjoined together the appearance or idea of the one immediately carries us to the idea of the other. Being fully satisfied on this head I make a third set of experiments in order to know whether anything be requisite beside the customary transition towards the production of this phenomenon of belief. I therefore change the first impression into an idea and observe that the customary transition to the correlative idea still remains yet there is in reality no belief nor persuasion. A present impression then is absolutely requisite to this whole operation and when after this I compare an impression with an idea and find that their only difference consists in their different degrees of force and vivacity I conclude upon the whole that belief is a more vivid and intense conception of an idea proceeding from its relation to a present impression. Thus all probable reasoning is nothing but a species of sensation. It is not solely in poetry and music we must follow our taste and sentiment but likewise in philosophy. When I am convinced of any principle it is only an idea which strikes more strongly upon me. When I give the preference to one set of arguments above another I do nothing but decide from my feeling concerning the superiority of their influence. Objects have no discoverable connection together nor is it from any other principle but custom operating upon the imagination that we can draw any inference from the appearance of one to the existence of another. It will here be worth our observation that the past experience on which all our judgments concerning cause and effect depend may operate on our mind in such an insensible manner as never to be taken notice of and may even in some measure be unknown to us. A person who stops short in his journey upon meeting a river in his way foresees the consequences of his proceeding forward and his knowledge of these consequences is conveyed to him by past experience which informs him of such certain conjunctions of causes and effects. But can we think that on this occasion he reflects on any past experience and calls to remembrance instances that he has seen or heard of in order to discover the effects of water on animal bodies? No, surely this is not the method in which he proceeds in his reasoning. The idea of sinking is so closely connected with that of water and the idea of suffocating with that of sinking that the mind makes the transition without the assistance of the memory. The custom operates before we have time for reflection. The objects seem so inseparable that we interpose not a moment's delay in passing from the one to the other. But as this transition proceeds from experience and not from any primary connection betwixt the ideas, we must necessarily acknowledge that experience may produce a belief and a judgment of causes and effects by a secret operation and without being once thought of. This removes all pretext if there yet remains any for asserting that the mind is convinced by reasoning of that principle that instances of which we have no experience must necessarily resemble those of which we have. For we here find that the understanding or imagination can draw inferences from past experience without reflecting on it much more without forming any principle concerning it or reasoning upon that principle. In general, we may observe that in all the most established and uniform conjunctions of causes and effects such as those of gravity, impulse, solidity, etc., the mind never carries its view expressly to consider any past experience. Though in other associations of objects which are more rare and unusual, it may assist the custom and transition of ideas by this reflection. Nay, we find in some cases that the reflection produces the belief without the custom or more properly speaking that the reflection produces the custom in an oblique and artificial manner. I explain myself. It is certain that not only in philosophy but even in common life we may attain the knowledge of a particular cause merely by one experiment provided it be made with judgment and after a careful removal of all foreign and superfluous circumstances. Now, as after one experiment of this kind the mind upon the appearance either of the cause or the effect can draw an inference concerning the existence of its correlative and as a habit can never be acquired merely by one instance it may be thought that belief cannot in this case be esteemed the effect of custom. But this difficulty will vanish if we consider that though we are here supposed to have had only one experiment of a particular effect yet we have many millions to convince us of this principle that like objects placed in like circumstances will always produce like effects and as this principle has established itself by a sufficient custom it bestows an evidence and firmness on any opinion to which it can be applied. The connection of the ideas is not habitual after one experiment but this connection is comprehended under another principle that is habitual which brings us back to our hypothesis. In all cases we transfer our experience to instances of which we have no experience either expressly or tacitly either directly or indirectly. I must not conclude this subject without observing that it is very difficult to talk of the operations of the mind with perfect propriety and exactness because common language has seldom made any very nice distinctions among them but has generally called by the same term all such as nearly resemble each other. And as this is a source almost inevitable of obscurity and confusion in the author so it may frequently give rise to doubts and objections in the reader which otherwise he would never have dreamed of. Thus my general position that an opinion or belief is nothing but a strong and lively idea derived from a present impression related to it may be liable to the following objection by reason of a little ambiguity in those words strong and lively. It may be said that not only an impression may give rise to reasoning but that an idea may also have the same influence especially upon my principle that all our ideas are derived from correspondent impressions. For suppose I form at present an idea of which I have forgot the correspondent impression. I am able to conclude from this idea that such an impression did once exist and as this conclusion is attended with belief it may be asked from whence are the qualities of force and vivacity derived which constitute this belief. And to this I answer very readily from the present idea. For as this idea is not here considered as the representation of any absent object but as a real perception in the mind of which we are intimately conscious it must be able to bestow on whatever is related to it the same quality call it firmness or solidity or force or vivacity with which the mind reflects upon it and is assured of its present existence. The idea here supplies the place of an impression and is entirely the same so far as regards our present purpose. Upon the same principles we need not be surprised to hear of the remembrance of an idea that is of the idea of an idea and of its force and vivacity superior to the loose conceptions of the imagination. In thinking of our past thoughts we not only delineate out the objects of which we were thinking but also conceive the action of the mind in the meditation of which it is impossible to give any definition or description but which everyone sufficiently understands. When the memory offers an idea of this and represents it as past it is easily conceived how that idea may have more vigor and firmness than when we think of a past thought of which we have no remembrance. After this anyone will understand how we may form the idea of an impression and of an idea and how we may believe the existence of an impression and of an idea. End of file 23