combination of chances implies a mixture of causes among the chances, 126; the question, 'how is a thing probable?'=the question what is the effect on the mind of a superior number of equal chances? 127; the vivacity of thought or the original impulse to come to a conclusion is split up into a number of impulses, and the probability of chances is the victory of one combination of there separate impulses over all others, 129; 'what the vulgar call chance is nothing but a secret and concealed cause, 130.
C. i. Probability of causes=(a) imperfect experience-i.e. a habit of transition not yet complete, (6) assurance modified by contrariety in experience, (c) uncertainty or contrariety of events not due to contingency in the causes but to the secret operation of contrary causes, 'since the connexion between all causes and effects is equally necessary,' 132 (cf. 404, 461 n); this contrariety results in a hesitating belief, (a) by weakening our habit of transition, 132; (b) indirectly, by dividing and afterwards joining in different parts that perfect habit which makes us conclude that instances of which we have no experience must necessarily resemble those of which we have,' 135 (cf. 105); probability 'a superior vivacity arising from the concurrence of a superior number of views,' 137; it is that amount of vivacity which remains when you have subtracted the vivacity produced by an inferior number of experiments from that which is produced by a superior number, 158.
ii. Two great principles of all arguments from causation. (a) no object in itself can afford a reason for drawing a conclusion beyond it, (b) constant conjunction of objects affords us no reason for drawing an inference concerning any objects beyond those of which we have experience, 139; the belief that a certain future event will occur derived from an operation of the fancy which extracts from the balance of experiments a single lively idea, 140; but a voluntary repetition of experiments does not produce this lively idea since 'these separate acts of the mind are not united by any common object producing them,' 140, ch xxii, xxiii; the minute differences in probabilities not felt, e.g. the difference between ninety-nine and one hundred experiments: our preference of the greater number based on general rules, 141, cf. 146, 173 (but cf. 103).
iii. Analogy, a third kind of probability of causes, where the resemblance of the present object to one of the objects conjoined is weak, and the transition correspondingly weak, 142.
D. Unphilosophical probability=(a) diminished assurance resulting from a diminished vivacity of the related impression owing to time or distance: such difference in degree of evidence not admitted as solid or legitimate, otherwise the force of an argument would vary from day to day, 143; we are also the victims of such probability when (b) we allow ourselves to be more influenced by a recent than
