On the Improvement of the Understanding/Part 1
First part of method
 (1) Let us then make a beginning with the first part of the method, which is, as we have said, to distinguish and separate the true idea from other perceptions, and to keep the mind from confusing with true ideas those which are false, fictitious, and doubtful. (2) I intend to dwell on this point at length, partly to keep a distinction so necessary before the reader's mind, and also because there are some who doubt of true ideas, through not having attended to the distinction between a true perception and all others. (3) Such persons are like men who, while they are awake, doubt not that they are awake, but afterwards in a dream, as often happens, thinking that they are surely awake, and then finding that they were in error, become doubtful even of being awake. (4) This state of mind arises through neglect of the distinction between sleeping and waking.
 (1) Meanwhile, I give warning that I shall not here give essence of every perception, and explain it through its proximate cause. (2) Such work lies in the province of philosophy. (3) I shall confine myself to what concerns method - that is, to the character of fictitious, false and doubtful perceptions, and the means of freeing ourselves therefrom. (4) Let us then first inquire into the nature of a fictitious idea.
 (1) Every perception has for its object either a thing considered as existing, or solely the essence of a thing. (2) Now "fiction" is chiefly occupied with things considered as existing. (3) I will, therefore, consider these first - I mean cases where only the existence of an object is feigned, and the thing thus feigned is understood, or assumed to be understood. (4) For instance, I feign that Peter, whom I know to have gone home, is gone to see me, [r] or something of that kind. (5) With what is such an idea concerned? (6) It is concerned with things possible, and not with things necessary or impossible.
 (1) I call a thing impossible when its existence would imply a contradiction; necessary, when its non-existence would imply a contradiction; possible, when neither its existence nor its non-existence imply a contradiction, but when the necessity or impossibility of its nature depends on causes unknown to us, while we feign that it exists. (2) If the necessity or impossibility of its existence depending on external causes were known to us, we could not form any fictitious hypotheses about it;
 (1) Whence it follows that if there be a God, or omniscient Being, such an one cannot form fictitious hypotheses. (2) For, as regards ourselves, when I know that I exist, [s] I cannot hypothesize that I exist or do not exist, any more than I can hypothesize an elephant that can go through the eye of a needle; nor when I know the nature of God, can I hypothesize that He or does not exist. [t] (54:3) The same thing must be said of the Chimaera, whereof the nature implies a contradiction. (4) From these considerations, it is plain, as I have already stated, that fiction cannot be concerned with eternal truths. [u]
 (1) But before proceeding further, I must remark, in passing, that the difference between the essence of one thing and the essence of another thing is the same as that which exists between the reality or existence of one thing and the reality or existence of another; therefore, if we wished to conceive the existence, for example, of Adam, simply by means of existence in general, it would be the same as if, in order to conceive his existence, we went back to the nature of being, so as to define Adam as a being. (2) Thus, the more existence is conceived generally, the more is it conceived confusedly and the more easily can it be ascribed to a given object. (55:3) Contrariwise, the more it is conceived particularly, the more is it understood clearly, and the less liable is it to be ascribed, through negligence of Nature's order, to anything save its proper object. (4) This is worthy of remark.
 (1) We now proceed to consider those cases which are commonly called fictions, though we clearly understood that the thing is not as we imagine it. (2) For instance, I know that the earth is round, but nothing prevents my telling people that it is a hemisphere, and that it is like a half apple carved in relief on a dish; or, that the sun moves round the earth, and so on. (56:3) However, examination will show us that there is nothing here inconsistent with what has been said, provided we first admit that we may have made mistakes, and be now conscious of them; and, further, that we can hypothesize, or at least suppose, that others are under the same mistake as ourselves, or can, like us, fall under it. (4) We can, I repeat, thus hypothesize so long as we see no impossibility. (56:5) Thus, when I tell anyone that the earth is not round, &c., I merely recall the error which I perhaps made myself, or which I might have fallen into, and afterwards I hypothesize that the person to whom I tell it, is still, or may still fall under the same mistake. (6) This I say, I can feign so long as I do not perceive any impossibility or necessity; if I truly understood either one or the other I should not be able to feign, and I should be reduced to saying that I had made the attempt.
 (1) It remains for us to consider hypotheses made in problems, which sometimes involve impossibilities. (2) For instance, when we say - let us assume that this burning candle is not burning, or, let us assume that it burns in some imaginary space, or where there are no physical objects. (3) Such assumptions are freely made, though the last is clearly seen to be impossible. (4) But, though this be so, there is no fiction in the case. (57:5) For, in the first case, I have merely recalled to memory, [x] another candle not burning, or conceived the candle before me as without a flame, and then I understand as applying to the latter, leaving its flame out of the question, all that I think of the former. (6) In the second case, I have merely to abstract my thoughts from the objects surrounding the candle, for the mind to devote itself to the contemplation of the candle singly looked at in itself only; I can then draw the conclusion that the candle contains in itself no causes for its own destruction, so that if there were no physical objects the candle, and even the flame, would remain unchangeable, and so on. (7) Thus there is here no fiction, but, [y] true and bare assertions.
 (1) Let us now pass on to the fictions concerned with essences only, or with some reality or existence simultaneously. (2) Of these we must specially observe that in proportion as the mind's understanding is smaller, and its experience multiplex, so will its power of coining fictions be larger, whereas as its understanding increases, its capacity for entertaining fictitious ideas becomes less. (58:3) For instance, in the same way as we are unable, while we are thinking, to feign that we are thinking or not thinking, so, also, when we know the nature of body we cannot imagine an infinite fly; or, when we know the nature of the soul, [z] we cannot imagine it as square, though anything may be expressed verbally. (4) But, as we said above, the less men know of nature the more easily can they coin fictitious ideas, such as trees speaking, men instantly changed into stones, or into fountains, ghosts appearing in mirrors, something issuing from nothing, even gods changed into beasts and men and infinite other absurdities of the same kind.
 (1) Some persons think, perhaps, that fiction is limited by fiction, and not by understanding; in other words, after I have formed some fictitious idea, and have affirmed of my own free will that it exists under a certain form in nature, I am thereby precluded from thinking of it under any other form. (2) For instance, when I have feigned (to repeat their argument) that the nature of body is of a certain kind, and have of my own free will desired to convince myself that it actually exists under this form, I am no longer able to hypothesize that a fly, for example, is infinite; so, when I have hypothesized the essence of the soul, I am not able to think of it as square, &c.
 (1) But these arguments demand further inquiry. (2) First, their upholders must either grant or deny that we can understand anything. If they grant it, then necessarily the same must be said of understanding, as is said of fiction. (3) If they deny it, let us, who know that we do know something, see what they mean. (4) They assert that the soul can be conscious of, and perceive in a variety of ways, not itself nor things which exist, but only things which are neither in itself nor anywhere else, in other words, that the soul can, by its unaided power, create sensations or ideas unconnected with things. (5) In fact, they regard the soul as a sort of god. (60:6) Further, they assert that we or our soul have such freedom that we can constrain ourselves, or our soul, or even our soul's freedom. (7) For, after it has formed a fictitious idea, and has given its assent thereto, it cannot think or feign it in any other manner, but is constrained by the first fictitious idea to keep all its other thoughts in harmony therewith. (8) Our opponents are thus driven to admit, in support of their fiction, the absurdities which I have just enumerated; and which are not worthy of rational refutation.
 (1) While leaving such persons in their error, we will take care to derive from our argument with them a truth serviceable for our purpose, namely, [61a] that the mind, in paying attention to a thing hypothetical or false, so as to meditate upon it and understand it, and derive the proper conclusions in due order therefrom, will readily discover its falsity; and if the thing hypothetical be in its nature true, and the mind pays attention to it, so as to understand it, and deduce the truths which are derivable from it, the mind will proceed with an uninterrupted series of apt conclusions; in the same way as it would at once discover (as we showed just now) the absurdity of a false hypothesis, and of the conclusions drawn from it.
 (1) We need, therefore, be in no fear of forming hypotheses, so long as we have a clear and distinct perception of what is involved. (2) For, if we were to assert, haply, that men are suddenly turned into beasts, the statement would be extremely general, so general that there would be no conception, that is, no idea or connection of subject and predicate, in our mind. (3) If there were such a conception we should at the same time be aware of the means and the causes whereby the event took place. (4) Moreover, we pay no attention to the nature of the subject and the predicate.
 (1) Now, if the first idea be not fictitious, and if all the other ideas be deduced therefrom, our hurry to form fictitious ideas will gradually subside. (2) Further, as a fictitious idea cannot be clear and distinct, but is necessarily confused, and as all confusion arises from the fact that the mind has only partial knowledge of a thing either simple or complex, and does not distinguish between the known and the unknown, and, again, that it directs its attention promiscuously to all parts of an object at once without making distinctions, it follows, first, that if the idea be of something very simple, it must necessarily be clear and distinct. (3) For a very simple object cannot be known in part, it must either be known altogether or not at all.
 (1) Secondly, it follows that if a complex object be divided by thought into a number of simple component parts, and if each be regarded separately, all confusion will disappear. (2) Thirdly, it follows that fiction cannot be simple, but is made up of the blending of several confused ideas of diverse objects or actions existent in nature, or rather is composed of attention directed to all such ideas at once, [64b] and unaccompanied by any mental assent. (3) Now a fiction that was simple would be clear and distinct, and therefore true, also a fiction composed only of distinct ideas would be clear and distinct, and therefore true. (4) For instance, when we know the nature of the circle and the square, it is impossible for us to blend together these two figures, and to hypothesize a square circle, any more than a square soul, or things of that kind.
 (1) Let us shortly come to our conclusion, and again repeat that we need have no fear of confusing with true ideas that which is only a fiction. (2) As for the first sort of fiction of which we have already spoken, when a thing is clearly conceived, we saw that if the existence of a that thing is in itself an eternal trut fiction can have no part in it; but if the existence of the conceived be not an eternal truth, we have only to be careful such existence be compared to the thing's essence, and to consider the order of nature. (64:3) As for the second sort of fiction, which we stated to be the result of simultaneously directing the attention, without the assent of the intellect, to different confused ideas representing different things and actions existing in nature, we have seen that an absolutely simple thing cannot be feigned, but must be understood, and that a complex thing is in the same case if we regard separately the simple parts whereof it is composed; we shall not even be able to hypothesize any untrue action concerning such objects, for we shall be obliged to consider at the same time the causes and manner of such action.
 (1) These matters being thus understood, let us pass on to consider the false idea, observing the objects with which it is concerned, and the means of guarding ourselves from falling into false perceptions. (2) Neither of these tasks will present much difficulty, after our inquiry concerning fictitious ideas. (3) The false idea only differs from the fictitious idea in the fact of implying a mental assent - that is, as we have already remarked, while the representations are occurring, there are no causes present to us, wherefrom, as in fiction, we can conclude that such representations do not arise from external objects: in fact, it is much the same as dreaming with our eyes open, or while awake. (67:4) Thus, a false idea is concerned with, or (to speak more correctly) is attributable to, the existence of a thing whereof the essence is known, or the essence itself, in the same way as a fictitious idea.
 (1) If attributable to the existence of the thing, it is corrected in the same way as a fictitious idea under similar circumstances. (2) If attributable to the essence, it is likewise corrected in the same way as a fictitious idea. (67:3) For if the nature of the thing known implies necessary existence, we cannot possible be in error with regard to its existence; but if the nature of the thing be not an eternal truth, like its essence, but contrariwise the necessity or impossibility of its existence depends on external causes, then we must follow the same course as we adopted in the of fiction, for it is corrected in the same manner.
 (1) As for false ideas concerned with essences, or even with actions, such perceptions are necessarily always confused, being compounded of different confused perceptions of things existing in nature, as, for instance, when men are persuaded that deities are present in woods, in statues, in brute beasts, and the like; that there are bodies which, by their composition alone, give rise to intellect; that corpses reason, walk about, and speak; that God is deceived, and so on. (68:2) But ideas which are clear and distinct can never be false: for ideas of things clearly and distinctly conceived are either very simple themselves, or are compounded from very simple ideas, that is, are deduced therefrom. (3) The impossibility of a very simple idea being false is evident to everyone who understands the nature of truth or understanding and of falsehood.
 (1) As regards that which constitutes the reality of truth, it is certain that a true idea is distinguished from a false one, not so much by its extrinsic object as by its intrinsic nature. (2) If an architect conceives a building properly constructed, though such a building may never have existed, and amy never exist, nevertheless the idea is true; and the idea remains the same, whether it be put into execution or not. (69:3) On the other hand, if anyone asserts, for instance, that Peter exists, without knowing whether Peter really exists or not, the assertion, as far as its asserter is concerned, is false, or not true, even though Peter actually does exist. (4) The assertion that Peter exists is true only with regard to him who knows for certain that Peter does exist.
 (1) Whence it follows that there is in ideas something real, whereby the true are distinguished from the false. (2) This reality must be inquired into, if we are to find the best standard of truth (we have said that we ought to determine our thoughts by the given standard of a true idea, and that method is reflective knowledge), and to know the properties of our understanding. (70:3) Neither must we say that the difference between true and false arises from the fact, that true knowledge consists in knowing things through their primary causes, wherein it is totally different from false knowledge, as I have just explained it: for thought is said to be true, if it involves subjectively the essence of any principle which has no cause, and is known through itself and in itself.
 (1) Wherefore the reality (forma) of true thought must exist in the thought itself, without reference to other thoughts; it does not acknowledge the object as its cause, but must depend on the actual power and nature of the understanding. (2) For, if we suppose that the understanding has perceived some new entity which has never existed, as some conceive the understanding of God before He created thing (a perception which certainly could not arise any object), and has legitimately deduced other thoughts from said perception, all such thoughts would be true, without being determined by any external object; they would depend solely on the power and nature of the understanding. (71:3) Thus, that which constitutes the reality of a true thought must be sought in the thought itself, and deduced from the nature of the understanding.
 (1) In order to pursue our investigation, let us confront ourselves with some true idea, whose object we know for certain to be dependent on our power of thinking, and to have nothing corresponding to it in nature. (2) With an idea of this kind before us, we shall, as appears from what has just been said, be more easily able to carry on the research we have in view. (72:3) For instance, in order to form the conception of a sphere, I invent a cause at my pleasure - namely, a semicircle revolving round its center, and thus producing a sphere. (4) This is indisputably a true idea; and, although we know that no sphere in nature has ever actually been so formed, the perception remains true, and is the easiest manner of conceiving a sphere. (72:5) We must observe that this perception asserts the rotation of a semicircle - which assertion would be false, if it were not associated with the conception of a sphere, or of a cause determining a motion of the kind, or absolutely, if the assertion were isolated. (6) The mind would then only tend to the affirmation of the sole motion of a semicircle, which is not contained in the conception of a semicircle, and does not arise from the conception of any cause capable of producing such motion. (72:7) Thus falsity consists only in this, that something is affirmed of a thing, which is not contained in the conception we have formed of that thing, as motion or rest of a semicircle. (8) Whence it follows that simple ideas cannot be other than true - e.g., the simple idea of a semicircle, of motion, of rest, of quantity, &c. (72:9) Whatsoever affirmation such ideas contain is equal to the concept formed, and does not extend further. (10) Wherefore we form as many simple ideas as we please, without any fear of error.
 (1) It only remains for us to inquire by what power our mind can form true ideas, and how far such power extends. (2) It is certain that such power cannot extend itself infinitely. (3) For when we affirm somewhat of a thing, which is not contained in the concept we have formed of that thing, such an affirmation shows a defect of our perception, or that we have formed fragmentary or mutilated ideas. (4) Thus we have seen that the notion of a semicircle is false when it is isolated in the mind, but true when it is associated with the concept of a sphere, or of some cause determining such a motion. (73:5) But if it be the nature of a thinking being, as seems, prima facie, to be the case, to form true or adequate thoughts, it is plain that inadequate ideas arise in us only because we are parts of a thinking being, whose thoughts - some in their entirety, others in fragments only - constitute our mind.
 (1) But there is another point to be considered, which was not worth raising in the case of fiction, but which give rise to complete deception - namely, that certain things presented to the imagination also exist in the understanding - in other words, are conceived clearly and distinctly. (2) Hence, so long as we do not separate that which is distinct from that which is confused, certainty, or the true idea, becomes mixed with indistinct ideas. (3) For instance, certain Stoics heard, perhaps, the term "soul," and also that the soul is immortal, yet imagined it only confusedly; they imaged, also, and understood that very subtle bodies penetrate all others, and are penetrated by none. (74:4) By combining these ideas, and being at the same time certain of the truth of the axiom, they forthwith became convinced that the mind consists of very subtle bodies; that these very subtle bodies cannot be divided &c.
 (1) But we are freed from mistakes of this kind, so long as we endeavor to examine all our perceptions by the standard of the given true idea. (2) We must take care, as has been said, to separate such perceptions from all those which arise from hearsay or unclassified experience. (3) Moreover, such mistakes arise from things being conceived too much in the abstract; for it is sufficiently self-evident that what I conceive as in its true object I cannot apply to anything else. (75:4) Lastly, they arise from a want of understanding of the primary elements of nature as a whole; whence we proceed without due order, and confound nature with abstract rules, which, although they be true enough in their sphere, yet, when misapplied, confound themselves, and pervert the order of nature. (5) However, if we proceed with as little abstraction as possible, and begin from primary elements - that is, from the source and origin of nature, as far back as we can reach, - we need not fear any deceptions of this kind.
 (1) As far as the knowledge of the origin of nature is concerned, there is no danger of our confounding it with abstractions. (2) For when a thing is conceived in the abstract, as are all universal notions, the said universal notions are always more extensive in the mind than the number of individuals forming their contents really existing in nature. (3) Again, there are many things in nature, the difference between which is so slight as to be hardly perceptible to the understanding; so that it may readily happen that such things are confounded together, if they be conceived abstractedly. (4) But since the first principle of nature cannot (as we shall see hereafter) be conceived abstractedly or universally, and cannot extend further in the understanding than it does in reality, and has no likeness to mutable things, no confusion need be feared in respect to the idea of it, provided (as before shown) that we possess a standard of truth. (5) This is, in fact, a being single and infinite [76z] ; in other words, it is the sum total of being, beyond which there is no being found. [76a]
 (1) Thus far we have treated of the false idea. We have now to investigate the doubtful idea - that is, to inquire what can cause us to doubt, and how doubt may be removed. (2) I speak of real doubt existing in the mind, not of such doubt as we see exemplified when a man says that he doubts, though his mind does not really hesitate. (77:3) The cure of the latter does not fall within the province of method, it belongs rather to inquiries concerning obstinacy and its cure.
 (1) Real doubt is never produced in the mind by the thing doubted of. (2) In other words, if there were only one idea in the mind, whether that idea were true or false, there would be no doubt or certainty present, only a certain sensation. (3) For an idea is in itself nothing else than a certain sensation. (4) But doubt will arise through another idea, not clear and distinct enough for us to be able to draw any certain conclusions with regard to the matter under consideration; that is, the idea which causes us to doubt is not clear and distinct. (5) To take an example. (78:6) Supposing that a man has never reflected, taught by experience or by any other means, that our senses sometimes deceive us, he will never doubt whether the sun be greater or less than it appears. (7) Thus rustics are generally astonished when they hear that the sun is much larger than the earth. (8) But from reflection on the deceitfulness of the senses [78a] doubt arises, and if, after doubting, we acquire a true knowledge of the senses, and how things at a distance are represented through their instrumentality, doubt is again removed.
 (1) Hence we cannot cast doubt on true ideas by the supposition that there is a deceitful Deity, who leads us astray even in what is most certain. (2) We can only hold such an hypothesis so long as we have no clear and distinct idea - in other words, until we reflect the knowledge which we have of the first principle of all things, and find that which teaches us that God is not a deceiver, and until we know this with the same certainty as we know from reflecting on the are equal to two right angles. (3) But if we have a knowledge of God equal to that which we have of a triangle, all doubt is removed. (79:4) In the same way as we can arrive at the said knowledge of a triangle, though not absolutely sure that there is not some arch-deceiver leading us astray, so can we come to a like knowledge of God under the like condition, and when we have attained to it, it is sufficient, as I said before, to remove every doubt which we can possess concerning clear and distinct ideas.
 (1) Thus, if a man proceeded with our investigations in due order, inquiring first into those things which should first be inquired into, never passing over a link in the chain of association, and with knowledge how to define his questions before seeking to answer them, he will never have any ideas save such as are very certain, or, in other words, clear and distinct; for doubt is only a suspension of the spirit concerning some affirmation or negation which it would pronounce upon unhesitatingly if it were not in ignorance of something, without which the knowledge of the matter in hand must needs be imperfect. (2) We may, therefore, conclude that doubt always proceeds from want of due order in investigation.
 (1) These are the points I promised to discuss in the first part of my treatise on method. (2) However, in order not to omit anything which can conduce to the knowledge of the understanding and its faculties, I will add a few words on the subject of memory and forgetfulness. (81:3) The point most worthy of attention is, that memory is strengthened both with and without the aid of the understanding. (4) For the more intelligible a thing is, the more easily is it remembered, and the less intelligible it is, the more easily do we forget it. (5) For instance, a number of unconnected words is much more difficult to remember than the same number in the form of a narration.
 (1) The memory is also strengthened without the aid of the understanding by means of the power wherewith the imagination or the sense called common, is affected by some particular physical object. (2) I say particular, for the imagination is only affected by particular objects. (3) If we read, for instance, a single romantic comedy, we shall remember it very well, so long as we do not read many others of the same kind, for it will reign alone in the memory (4) If, however, we read several others of the same kind, we shall think of them altogether, and easily confuse one with another. (82:5) I say also, physical. (6) For the imagination is only affected by physical objects. (7) As, then, the memory is strengthened both with and without the aid of the understanding, we may conclude that it is different from the understanding, and that in the latter considered in itself there is neither memory nor forgetfulness.
 (1) What, then, is memory? (2) It is nothing else than the actual sensation of impressions on the brain, accompanied with the thought of a definite duration, [83d] of the sensation. (3) This is also shown by reminiscence. (4) For then we think of the sensation, but without the notion of continuous duration; thus the idea of that sensation is not the actual duration of the sensation or actual memory. (83:5) Whether ideas are or are not subject to corruption will be seen in philosophy. (6) If this seems too absurd to anyone, it will be sufficient for our purpose, if he reflect on the fact that a thing is more easily remembered in proportion to its singularity, as appears from the example of the comedy just cited. (83:7) Further, a thing is remembered more easily in proportion to its intelligibility; therefore we cannot help remember that which is extremely singular and sufficiently intelligible.
 (1) Thus, then, we have distinguished between a true idea and other perceptions, and shown that ideas fictitious, false, and the rest, originate in the imagination - that is, in certain sensations fortuitous (so to speak) and disconnected, arising not from the power of the mind, but from external causes, according as the body, sleeping or waking, receives various motions. (2) But one may take any view one likes of the imagination so long as one acknowledges that it is different from the understanding, and that the soul is passive with regard to it. (3) The view taken is immaterial, if we know that the imagination is something indefinite, with regard to which the soul is passive, and that we can by some means or other free ourselves therefrom with the help of the understanding. (4) Let no one then be astonished that before proving the existence of body, and other necessary things, I speak of imagination of body, and of its composition. (5) The view taken is, I repeat, immaterial, so long as we know that imagination is something indefinite, &c.
 (1) As regards as a true idea, we have shown that it is simple or compounded of simple ideas; that it shows how and why something is or has been made; and that its subjective effects in the soul correspond to the actual reality of its object. (2) This conclusion is identical with the saying of the ancients, that true proceeds from cause to effect; though the ancients, so far as I know, never formed the conception put forward here that the soul acts according to fixed laws, and is as it were an immaterial automaton.
 (1) Hence, as far as is possible at the outset, we have acquired a knowledge of our understanding, and such a standard of a true idea that we need no longer fear confounding truth with falsehood and fiction. (2) Neither shall we wonder why we understand some things which in nowise fall within the scope of the imagination, while other things are in the imagination but wholly opposed to the understanding, or others, again, which agree therewith. (3) We now know that the operations, whereby the effects of imagination are produced, take place under other laws quite different from the laws of the understanding, and that the mind is entirely passive with regard to them.
 (1) Whence we may also see how easily men may fall into grave errors through not distinguishing accurately between the imagination and the understanding; such as believing that extension must be localized, that it must be finite, that its parts are really distinct one from the other, that it is the primary and single foundation of all things, that it occupies more space at one time than at another and other similar doctrines, all entirely opposed to truth, as we shall duly show.
 (1) Again, since words are a part of the imagination - that is, since we form many conceptions in accordance with confused arrangements of words in the memory, dependent on particular bodily conditions, - there is no doubt that words may, equally with the imagination, be the cause of many and great errors, unless we strictly on our guard.
 (1) Moreover, words are formed according to popular fancy and intelligence, and are, therefore, signs of things as existing in the imagination, not as existing in the understanding. (2) This is evident from the fact that to all such things as exist only in the understanding, not in the imagination, negative names are often given, such as incorporeal, infinite, &c. (3) So, also, many conceptions really affirmative are expressed negatively, and vice versa, such as uncreate, independent, infinite, immortal, &c., inasmuch as their contraries are much more easily imagined, and, therefore, occurred first to men, and usurped positive names. (89:4) Many things we affirm and deny, because the nature of words allows us to do so, though the nature of things does not. (5) While we remain unaware of this fact, we may easily mistake falsehood for truth.
 (1) Let us also beware of another great cause of confusion, which prevents the understanding from reflecting on itself. (2) Sometimes, while making no distinction between the imagination and the intellect, we think that what we more readily imagine is clearer to us; and also we think that what we imagine we understand. (3) Thus, we put first that which should be last: the true order of progression is reversed, and no legitimate conclusion is drawn.
[r]^ See below the note on hypotheses, whereof we have a clear understanding; the fiction consists in saying that such hypotheses exist in heavenly bodies.
[s]^ (1) As a thing, when once it is understood, manifests itself, we have need only of an example without further proof. (2) In the same way the contrary has only to be presented to our minds to be recognized as false, as will forthwith appear when we come to discuss fiction concerning essences.
[t]^ Observe, that although many assert that they doubt whether God exists, they have nought but his name in their minds, or else some fiction which they call God: this fiction is not in harmony with God's real nature, as we will duly show.
[u]^ (1) I shall presently show that no fiction can concern eternal truths. By an eternal truth, I mean that which being positive could never become negative. (2) Thus it is a primary and eternal truth that God exists, but it is not an eternal truth that Adam thinks. (3) That the Chimaera does not exist is an eternal truth, that Adam does not think is not so.
[x]^ (1) Afterwards, when we come to speak of fiction that is concerned with essences, it will be evident that fiction never creates or furnishes the mind with anything new; only such things as are already in the brain or imagination are recalled to the memory, when the attention is directed to them confusedly and all at once. (2) For instance, we have remembrance of spoken words and of a tree; when the mind directs itself to them confusedly, it forms the notion of a tree speaking. (3) The same may be said of existence, especially when it is conceived quite generally as an entity; it is then readily applied to all things together in the memory. (4) This is specially worthy of remark.
[y]^ We must understand as much in the case of hypotheses put forward to explain certain movements accompanying celestial phenomena; but from these, when applied to the celestial motions, we any draw conclusions as to the nature of the heavens, whereas this last may be quite different, especially as many other causes are conceivable which would account for such motions.
[z]^ (1) It often happens that a man recalls to mind this word soul, and forms at the same time some corporeal image: as the two representations are simultaneous, he easily thinks that he imagines and feigns a corporeal soul: thus confusing the name with the thing itself. (2) I here beg that my readers will not be in a hurry to refute this proposition; they will, I hope, have no mind to do so, if they pay close attention to the examples given and to what follows.
[61a]^ (1) Though I seem to deduce this from experience, some may deny its cogency because I have given no formal proof. (2) I therefore append the following for those who may desire it. (3) As there can be nothing in nature contrary to nature's laws, since all things come to pass by fixed laws, so that each thing must irrefragably produce its own proper effect, it follows that the soul, as soon as it possesses the true conception of a thing, proceeds to reproduce in thought that thing's effects. (4) See below, where I speak of the false idea.
[64b]^ (1) Observe that fiction regarded in itself, only differs from dreams in that in the latter we do not perceive the external causes which we perceive through the senses while awake. (2) It has hence been inferred that representations occurring in sleep have no connection with objects external to us. (3) We shall presently see that error is the dreaming of a waking man: if it reaches a certain pitch it becomes delirium.
[76z]^ These are not attributes of God displaying His essence, as I will show in my philosophy.
[76a]^ (1) This has been shown already. (2) For if such a being did not exist it would never be produced; therefore the mind would be able to understand more than nature could furnish; and this has been shown above to be false.
[78a]^ (1) That is, it is known that the senses sometimes deceive us. (2) But it is only known confusedly, for it is not known how they deceive us.
[83d]^ (1) If the duration be indefinite, the recollection is imperfect; this everyone seems to have learnt from nature. (2) For we often ask, to strengthen our belief in something we hear of, when and where it happened; though ideas themselves have their own duration in the mind, yet, as we are wont to determine duration by the aid of some measure of motion which, again, takes place by aid of imagination, we preserve no memory connected with pure intellect.