§ 10. Wolf.
Project Gutenberg EPUB3 edition
Schopenhauer, Arthur and Hillebrand, Karl, Mme.
The first writer who explicitly separated the two chief significations of our principle, and stated the difference between them in detail, was therefore Wolf. Wolf, however, does not place the principle of sufficient reason in Logic, as is now the custom, but in Ontology. True, in § 71 he urges the necessity of not confounding the principle of sufficient reason of knowing with that of cause and effect; still he does not clearly determine here wherein the difference consists. Indeed, he himself mistakes the one for the other; for he quotes instances of cause and effect in confirmation of the principium rationis sufficientis in this very chapter, de ratione sufficiente, §§ 70, 74, 75, 77, which, had he really wished to preserve that distinction, ought rather to have been quoted in the chapter de causis of the same work. In said chapter he again brings forward precisely similar instances, and once more enunciates the principium cognoscendi (§ 876), which does not certainly belong to it, having been already discussed, yet which serves to introduce the immediately following clear and definite distinction between this principle and the law of causality, §§ 881-884. Principium, he continues, dicitur id, quod in se continet rationem alterius; and he distinguishes three kinds:
1. Principium Fiendi (causa), which he defines as ratio actualitatis alterius, e.g., si lapis calescit, ignis aut radii solares sunt rationes, cur calor lapidi insit.—
2. Principium Essendi, which he defines as ratio possibilitatis alterius; in eodem, exemplo, ratio possibilitatis, cur lapis calorem recipere possit, est in essentia seu modo compositionis lapidis. This last conception seems to me inadmissible. If it has any meaning at all, possibility means correspondence with the general conditions of experience known to us à priori, as Kant has sufficiently shown. From these conditions we know, with respect to Wolf's instance of the stone, that changes are possible as effects proceeding from causes: we know, that is, that one state can succeed another, if the former contains the conditions for the latter. In this case we find, as effect, the state of being warm in the stone; as cause, the preceding state of a limited capacity for warmth in the stone and its contact with free heat. Now, Wolf's naming the first mentioned property of this state principium essendi, and the second, principium fiendi, rests upon a delusion caused by the fact that, so far as the stone is concerned, the conditions are more lasting and can therefore wait longer for the others.
That the stone should be as it is: that is, that it should be chemically so constituted as to bring with it a particular degree of specific heat, consequently a capacity for heat which stands in inverse proportion to its specific heat; that besides it should, on the other hand, come into contact with free heat, is the consequence of a whole chain of antecedent causes, all of them principia fiendi; but it is the coincidence of circumstances on both sides which primarily constitutes that condition, upon which, as cause, the becoming warm depends, as effect. All this leaves no room for Wolf's principium essendi, which I therefore do not admit, and concerning which I have here entered somewhat into detail, partly because I mean to use the word myself later on in a totally different sense; partly also, because this explanation contributes to facilitate the comprehension of the law of causality.—
3. Wolf, as we have said, distinguishes a Principium Cognoscendi, and refers also under causa to a causa impulsiva, sive ratio voluntatem determinans.