Part 5

(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, 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.

(1) Now, in order at length to pass on to the second part of this method, I shall first set forth the object aimed at, and next the means for its attainment. (2) The object aimed at is the acquisition of clear and distinct ideas, such as are produced by the pure intellect, and not by chance physical motions. (3) In order that all ideas may be reduced to unity, we shall endeavor so to associate and arrange them that our mind may, as far as possible, reflect subjectively the reality of nature, both as a whole and as parts.

(1) As for the first point, it is necessary (as we have said) for our purpose that everything should be conceived, either solely through its essence, or through its proximate cause. (2) If the thing be self-existent, or, as is commonly said, the cause of itself, it must be understood through its essence only; if it be not self-existent, but requires a cause for its existence, it must be understood through its proximate cause. (3) For, in reality, the knowledge, of an effect is nothing else than the acquisition of more perfect knowledge of its cause.

(1) Therefore, we may never, while we are concerned with inquiries into actual things, draw any conclusion from abstractions; we shall be extremely careful not to confound that which is only in the understanding with that which is in the thing itself. (2) The best basis for drawing a conclusion will be either some particular affirmative essence, or a true and legitimate definition. (93:3) For the understanding cannot descend from universal axioms by themselves to particular things, since axioms are of infinite extent, and do not determine the understanding to contemplate one particular thing more than another.

(1) Thus the true method of discovery is to form thoughts from some given definition. (2) This process will be the more fruitful and easy in proportion as the thing given be better defined. (3) Wherefore, the cardinal point of all this second part of method consists in the knowledge of the conditions of good definition, and the means of finding them. (4) I will first treat of the conditions of definition.

(1) A definition, if it is to be called perfect, must explain the inmost essence of a thing, and must take care not to substitute for this any of its properties. (2) In order to illustrate my meaning, without taking an example which would seem to show a desire to expose other people's errors, I will choose the case of something abstract, the definition of which is of little moment. (95:3) Such is a circle. (4) If a circle be defined as a figure, such that all straight lines drawn from the center to the circumference are equal, every one can see that such a definition does not in the least explain the essence of a circle, but solely one of its properties. (5) Though, as I have said, this is of no importance in the case of figures and other abstractions, it is of great importance in the case of physical beings and realities: for the properties of things are not understood so long as their essences are unknown. (6) If the latter be passed over, there is necessarily a perversion of the succession of ideas which should reflect the succession of nature, and we go far astray from our object.

In order to be free from this fault, the following rules should be observed in definition:--

I. (1) If the thing in question be created, the definition must (as we have said) comprehend the proximate cause. (2) For instance, a circle should, according to this rule, be defined as follows: the figure described by any line whereof one end is fixed and the other free. (3) This definition clearly comprehends the proximate cause.

II. (4) A conception or definition of a thing should be such that all the properties of that thing, in so far as it is considered by itself, and not in conjunction with other things, can be deduced from it, as may be seen in the definition given of a circle: for from that it clearly follows that all straight lines drawn from the center to the circumference are equal. (5) That this is a necessary characteristic of a definition is so clear to anyone, who reflects on the matter, that there is no need to spend time in proving it, or in showing that, owing to this second condition, every definition should be affirmative. (6) I speak of intellectual affirmation, giving little thought to verbal affirmations which, owing to the poverty of language, must sometimes, perhaps, be expressed negatively, though the idea contained is affirmative.

The rules for the definition of an uncreated thing are as follows:--

I. The exclusion of all idea of cause--that is, the thing must not need explanation by Anything outside itself.

II. When the definition of the thing has been given, there must be no room for doubt as to whether the thing exists or not.

III. It must contain, as far as the mind is concerned, no substantives which could be put into an adjectival form; in other words, the object defined must not be explained through abstractions.

IV. Lastly, though this is not absolutely necessary, it should be possible to deduce from the definition all the properties of the thing defined.

All these rules become obvious to anyone giving strict attention to the matter.

(1) I have also stated that the best basis for drawing a conclusion is a particular affirmative essence. (2) The more specialized the idea is, the more it is distinct, and therefore clear. (3) Wherefore a knowledge of particular things should be sought for as diligently as possible.

(1) As regards the order of our perceptions, and the manner in which they should be arranged and united, it is necessary that, as soon as is possible and rational, we should inquire whether there be any being (and, if so, what being), that is the cause of all things, so that its essence, represented in thought, may be the cause of all our ideas, and then our mind will to the utmost possible extent reflect nature. (2) For it will possess, subjectively, nature's essence, order, and union. (3) Thus we can see that it is before all things necessary for us to deduce all our ideas from physical things--that is, from real entities, proceeding, as far as may be, according to the series of causes, from one real entity to another real entity, never passing to universals and abstractions, either for the purpose of deducing some real entity from them, or deducing them from some real entity. (4) Either of these processes interrupts the true progress of the understanding.

(1) But it must be observed that, by the series of causes and real entities, I do not here mean the series of particular and mutable things, but only the series of fixed and eternal things. (2) It would be impossible for human infirmity to follow up the series of particular mutable things, both on account their multitude, surpassing all calculation, and on account of the infinitely diverse circumstances surrounding one and the same thing, any one of which may be the cause of its existence or non-existence. (3) Indeed, their existence has no connection with their essence, or (as we have said already) is not an eternal truth.

(1) Neither is there any need that we should understand their series, for the essences of particular mutable things are not to be gathered from their series or order of existence, which would furnish us with nothing beyond their extrinsic denominations, their relations, or, at most, their circumstances, all of which are very different from their inmost essence. (101:2) This inmost essence must be sought solely from fixed and eternal things, and from the laws, inscribed (so to speak) in those things as in their true codes, according to which all particular things take place and are arranged; nay, these mutable particular things depend so intimately and essentially (so to phrase it) upon the fixed things, that they cannot either be conceived without them.

(1) But, though this be so, there seems to be no small difficulty in arriving at the knowledge of these particular things, for to conceive them all at once would far surpass the powers of the human understanding. (2) The arrangement whereby one thing is understood, before another, as we have stated, should not be sought from their series of existence, nor from eternal things. (3) For the latter are all by nature simultaneous. (4) Other aids are therefore needed besides those employed for understanding eternal things and their laws. (5) However, this is not the place to recount such aids, nor is there any need to do so, until we have acquired a sufficient knowledge of eternal things and their infallible laws, and until the nature of our senses has become plain to us.