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652 objects,' 165; just as the necessity by which twice two=four 'lies only in the act of understanding by which we compare these ideas.' Power and necessity are qualities of perceptions, not of objects, and are internally felt by the soul, not perceived externally in bodies, 166 (cf. 408); propensity of the mind to 'spread itself on external objects,' 167; we are driven by our nature to seek for an efficacious quality in objects, which yet really lies only in ourselves, 266; still the operation of nature are independent of our thought and reasoning, e.g. the contiguity, succession and resemblance of objects 'is independent of and antecedent to the operations of the understanding,' 168; 'the uniting 'principle among our internal perceptions is as unintelligible as that among external objects,' 169 (cf. 636).

Two definitions of cause, 170.

§ 10. Corollaries: (a) all causes are of the same kind—no distinction between efficient, formal, etc., nor between cause and occasion (in pride and love we distinguish between the quality which operates, the subject in which it is placed, and the object, 379, 185, 330), (cf. 174, 504); (b) only one kind of necessity—no distinction between physical and moral necessity: also no medium between chance and an absolute necessity, 171 (cf. § 8. C.); the distinction between power and the exercise of it invalid, 172 (cf. 12); but admissible in morals, 311 (v. Power); (c) no absolute or metaphysical necessity that every beginning of existence should be attended by a cause, 172 (cf. § 5); (d) 'we can never have any reason to believe that an object exists of which we cannot fonn an idea,' 172.

§ 11. Rule by which to judge of causes and effects, 173 f. (cf. 146); anything may produce anything,' i.e. 'when objects are not contrary nothing hinders them from having that constant conjunction on which the relation of cause and effect totally depends,' and only existence and non-existence are contrary, 173-341; 'the same cause always produces the same effect, and the same effect never arises but from the same cause: this principle we derive from experience,' 173 [methods of induction, 174]; 'an object which exists for any time in its full perfection without any effect, is not the sole cause of that effect,' 174; these rules easy to invent, but hard to apply, especially in morals, where the circumstances are very complicated, and where many of our sentiments are 'even unknown in their existence,' 175 (cf. 110); difficult to distinguish the chief cause out of a number, 504; no multiplicity of causes in nature, 282, 578; uncertainty and variety of causes in the natural world, 461 n (cf. 110).

§ 12. Matter the cause of our perceptions, 246 f.; no reason a priori why thought should not be caused by matter: though there appears no manner of connexion between motion or thought, the case is the same with all causes and edects, 247; matter actually