THE THEORY OF PROBABILITY. 247 



relations exceeding our powers of treatment. The infinitely 

 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 succession 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 many persons, 

 however, a remarkable series of successes will produce a 

 degree of excitement rendering continued success almost 

 impossible. 



Attempts to apply the theory of probabilities to the 

 results of judicial proceedings have proved of little value, 

 simply because the conditions are far too intricate. As 

 Laplace said, g 'Tant de passions, d'interets divers et de 

 circonstances compliquent les questions relatives a ces 

 objets, qu'elles sont presque toujours insolubles.' Men 

 acting on a jury, or giving evidence before a court, are 

 subject to so many complex influences that no mathema- 

 tical formulae can be framed to express the real conditions. 

 Jurymen or even judges on the bench cannot be regarded 

 as acting independently, with a definite probability in 

 favour of each delivering a correct judgment. Each man 

 of the jury is more or less influenced by the opinion of the 

 others, and there are subtle effects of character and manner 

 and strength of mind which defy human analysis. Even 

 in physical science we shall in comparatively few cases be 

 able to apply the theory in a definite manner, because the 



8 Quoted by Todhunter, 'History of the Theory of Probability,' p. 410. 



