x.] THE THEORY OF PROBABILITY. 215 



Locke remarks, "He that will not stir till he infallibly 

 knows the business he goes about will succeed, will 

 have but little else to do but to sit still and perish." l 

 There is not a moment of our lives when we do not lie 

 under a slight danger of death, or some most terrible fate. 

 There is not a single action of eating, drinking, sitting 

 down, or standing up, which has not proved fatal to some 

 person. Several philosophers have tried to assign the 

 limit of the probabilities which we regard as zero ; Buffon 

 named T^^, because it is the probability, practically 

 disregarded, that a man of 56 years of age will die the next 

 day. Pascal remarked that a man would be esteemed a 

 fool for hesitating to accept death when three dice gave 

 sixes twenty times running, if his reward in case of a 

 different result was to be a crown ; but as the chance of 

 death in question is only I -r- 6 60 , or unity divided by 

 a number of 47 places of figures, we may be said to incur 

 greater risks every day for less motives. There is far 

 greater risk of death, for instance, in a game of cricket or 

 a visit to the rink. 



Nothing is more requisite than to distinguish carefully 

 between the truth of a theory and the truthful application 

 of the theory to actual circumstances. As a general rule, 

 events in nature and art will present a complexity of 

 relations exceeding our powers of treatment. The intricate 

 action of the mind often intervenes and renders complete 

 analysis hopeless. If, for instance, the probability that 

 a marksman shall hit the target in a single shot be I in 

 10, we might seem to have no difficulty in calculating 

 the probability of any sucession of hits ; thus the proba- 

 bility of three successive hits would be one in a thousand. 

 But, in reality, the confidence and experience derived from 

 the first successful shot would render a second success 

 more probable. The events are not really independent, 

 and there would generally be a far greater preponderance 

 of runs of apparent luck, than a simple calculation of 

 probabilities could account for. In some persons, howe v er, 

 a remarkable series of successes will produce a degree of 

 excitement rendering continued success almost impossible. 



Attempts to apply the theory of probability to the 



1 tfssay concerning Human Understanding, bk. iv. eh. 14. j. 



