1p8sc2.md (4796B)
1 No doubt it will be difficult for those who think about things loosely, and have 2 not been accustomed to know them by their primary causes, to comprehend the 3 demonstration of Prop. vii.: for such persons make no distinction between the 4 modifications of substances and the substances themselves, and are ignorant of 5 the manner in which things are produced; hence they may attribute to substances 6 the beginning which they observe in natural objects. Those who are ignorant of 7 true causes, make complete confusion–think that trees might talk just as well 8 as men–that men might be formed from stones as well as from seed; and imagine 9 that any form might be changed into any other. So, also, those who confuse the 10 two natures, divine and human, readily attribute human passions to the deity, 11 especially so long as they do not know how passions originate in the mind. But, 12 if people would consider the nature of substance, they would have no doubt about 13 the truth of Prop. vii. In fact, this proposition would be a universal axiom, 14 and accounted a truism. For, by substance, would be understood that which is in 15 itself, and is conceived through itself–that is, something of which the 16 conception requires not the conception of anything else; whereas modifications 17 exist in something external to themselves, and a conception of them is formed by 18 means of a conception of the thing in which they exist. Therefore, we may have 19 true ideas of non–existent modifications; for, although they may have no actual 20 existence apart from the conceiving intellect, yet their essence is so involved 21 in something external to themselves that they may through it be conceived. 22 Whereas the only truth substances can have, external to the intellect, must 23 consist in their existence, because they are conceived through themselves. 24 Therefore, for a person to say that he has a clear and distinct–that is, a 25 true–idea of a substance, but that he is not sure whether such substance 26 exists, would be the same as if he said that he had a true idea, but was not 27 sure whether or no it was false (a little consideration will make this plain); 28 or if anyone affirmed that substance is created, it would be the same as saying 29 that a false idea was true–in short, the height of absurdity. It must, then, 30 necessarily be admitted that the existence of substance as its essence is an 31 eternal truth. And we can hence conclude by another process of reasoning–that 32 there is but one such substance. I think that this may profitably be done at 33 once; and, in order to proceed regularly with the demonstration, we must 34 premise:-— 35 36 1. The true definition of a thing neither involves nor expresses anything beyond 37 the nature of the thing defined. From this it follows that-— 38 39 2. No definition implies or expresses a certain number of individuals, inasmuch 40 as it expresses nothing beyond the nature of the thing defined. For instance, 41 the definition of a triangle expresses nothing beyond the actual nature of a 42 triangle: it does not imply any fixed number of triangles. 43 44 3. There is necessarily for each individual existent thing a cause why it should 45 exist. 46 47 4. This cause of existence must either be contained in the nature and definition 48 of the thing defined, or must be postulated apart from such definition. 49 50 It therefore follows that, if a given number of individual things exist in 51 nature, there must be some cause for the existence of exactly that number, 52 neither more nor less. For example, if twenty men exist in the universe (for 53 simplicity's sake, I will suppose them existing simultaneously, and to have had 54 no predecessors), and we want to account for the existence of these twenty men, 55 it will not be enough to show the cause of human existence in general; we must 56 also show why there are exactly twenty men, neither more nor less: for a cause 57 must be assigned for the existence of each individual. Now this cause cannot be 58 contained in the actual nature of man, for the true definition of man does not 59 involve any consideration of the number twenty. Consequently, the cause for the 60 existence of these twenty men, and, consequently, of each of them, must 61 necessarily be sought externally to each individual. Hence we may lay down the 62 absolute rule, that everything which may consist of several individuals must 63 have an external cause. And, as it has been shown already that existence 64 appertains to the nature of substance, existence must necessarily be included in 65 its definition; and from its definition alone existence must be deducible. But 66 from its definition (as we have shown, notes ii., iii.), we cannot infer the 67 existence of several substances; therefore it follows that there is only one 68 substance of the same nature. Q.E.D. 69 70