e. g. in discovering a particular cause by one experiment, 104; but in this case custom has already established the principle 'that like objects placed in like circumstances will always produce like effects' (cf. 89, 90, 134), and this habitual principle 'comprehends' the connexion of the ideas which is not habitual after one experiment, 105.
C. Belief arises only from causation, 107; custom and the relation of cause and effect give our ideas as much reality as those of the memory and senses—indeed, realities may be divided into two classes—the objects of the memory and the senses, and the objects of the judgment, e.g. the idea of Rome, 108; the effect of the relations of contiguity and resemblance when single is uncertain, for they can be feigned arbitrarily and are subject to caprice, whereas custom is unchangeable and irresistible, 109; in arguments from cause and effect we employ principles of imagination, which are permanent, irresistible, and universal, 225 (cf. 231, 267); the objects presented by the relation of cause and effect are 'fixed and unalterable,' the mind cannot hesitate or choose the idea to which it shall pass from a given impression, 110 (cf. 175, 461 n, 504); still resemblance and contiguity augment the vivacity of any conception, III f.; the want of resemblance especially weakens belief and overthrown what custom has established, 114.
D. Two kinds of custom, q. v. one indirectly giving vivacity to an idea by producing an easy transition from an impression, the other directly introducing a lively idea into the mind and so producing belief, 115; this done by education, 116, which, however, is an artificial and not a natural cause, and so not regarded by philosophers as an adequate ground of belief, 'though in reality it be built on almost the same foundation of custom and repetition as our reasonings from causes and effects, 117 (cf 145 f.); education 'a fallacious ground of assent to any opinion,' 118.
E. Reasoning from causation is able to operate on our will and passions (q. v.), 119; as belief excites the passions so the passions excite belief; 120; a lively imagination, madness, and folly influence the judgment and produce belief by enlivening the ideas just as completely as inference and sensation, 123; causation where united with contiguity and resemblance produces sympathy, 318, 320; an action 'obliquely' caused by a judgment, 459; reason can never cause a passion but is perfectly inert and inactive, 458, 415-416 (cf. 103).
§ 8. [Probability] A. Arguments from cause and effect not probable in the ordinary sense of the word, since they are free from doubt and uncertainty though based on experience, 124; two kinds of probability, one founded on chance, the other on causes, 124.
B. Chance, the negation of cause,=total indifference or absence of determination in thought; all chances equal, 125; the calculation or
