SECT. 10.] On certain kinds of Groups or Series. 13 



required. It is altogether unnecessary, for instance, to form 

 any opinion upon the questions discussed in metaphysics as 

 to the independent existence of substances. We have dis 

 covered, on examination, a series composed of groups of 

 substances and attributes, or of attributes alone. At such 

 a series we stop, and thence investigate our rules of infer 

 ence ; into what these substances or attributes would them 

 selves be ultimately analysed, if taken in hand by the 

 psychologist or metaphysician, it is no business of ours to 

 enquire here. 



10. The stage then which we have now reached is 

 that of having discovered a quantity of things (they prove 

 on analysis to be groups of things) which are capable of 

 being classified together, and are best regarded as consti 

 tuting a series. The distinctive peculiarity of this series is 

 our finding in it an order, gradually emerging out of disorder, 

 and showing in time a marked and unmistakeable uniformity. 



The impression which may possibly be derived from the 

 description of such a series, and which the reader will pro 

 bably already entertain if he have studied Probability before, 

 is that the gradual evolution of this order is indefinite, and 

 its approach therefore to perfection unlimited. And many of 

 the examples commonly selected certainly tend to confirm 

 such an impression. But in reference to the theory of the 

 subject it is, I am convinced, an error, and one liable to lead 

 to much confusion. 



The lines which have been prefixed as a motto to this 

 work, &quot; So careful of the type she seems, so careless of the 

 single life,&quot; are soon after corrected by the assertion that 

 the type itself, if we regard it for a long time, changes, 

 and then vanishes and is succeeded by others. So in Pro 

 bability; that uniformity which is found in the long run, 

 and which presents so great a contrast to the individual 



