SECT. 4.] On certain kinds of Groups or Series. 7 



there should be as many as eight heads and therefore as few 



as two tails, or vice versa. But take a thousand throws, and 



it becomes in turn exceedingly likely that there should be 



j as much as, or more than, a difference of six between the 



| respective numbers. On the other hand the proportion of 



! heads to tails in the case of the thousand throws will be very 



much nearer to unity, in most cases, than when we only took 



, ten. In other words, the longer a game of chance continues 



the larger are the spells and runs of luck in themselves, but 



the less their relative proportions to the whole amounts 



| involved. 



4. In speaking as above of events or things as to the 

 details of which we know little or nothing, it is not of course 

 implied that our ignorance about them is complete and uni 

 versal, or, what comes to the same thing, that irregularity 

 may be observed in all their qualities. All that is meant is 

 that there are some qualities or marks in them, the existence 

 of which we are not able to predicate with certainty in the 

 individuals. With regard to all their other qualities there 

 may be the utmost uniformity, and consequently the most 

 complete certainty. The irregularity in the length of human 

 life is notorious, but no one doubts the existence of such 

 organs as a heart and brains in any person whom he happens 

 to meet. And even in the qualities in which the irregularity 

 is observed, there are often, indeed generally, positive limits 

 within which it will be found to be confined. No person, 

 for instance, can calculate what may be the length of any 

 particular life, but we feel perfectly certain that it will not 

 stretch out to 150 years. The irregularity of the individual 

 instances is only shown in certain respects, as e.g. the length 

 of the life, and even in these respects it has its limits. The 

 same remark will apply to most of the other examples with 

 which we shall be concerned. The disorder in fact is not 



