KNOWLEDGE BY CAUSES 343 



time). Thus also I have reached other general notions. It seems 

 then that I have gathered many notions of what seem to me uni- 

 formities in nature (Maws' of nature) by this process of simple 

 enumeration. Such a process is a form of reasoning, but it is the 

 most rudimentary form. " This is the kind of induction which is 

 natural to the mind when unaccustomed to scientific efforts" 1 

 " True knowledge is knowledge by causes. For that knowledge 

 that proceeds by simple enumeration is a puerile thing, and con- 

 cludes uncertainly, and is exposed to danger from any con- 

 tradictory instance, and for the most part pronounces from fewer 

 instances than it ought, and of these only from such as are at 

 hand." 2 " Popular notions are usually founded on induction by 

 simple enumeration ; in science it carries us but a little way, we 

 are forced to begin with it ; we must often rely on it provisionally 

 in the absence of means of more searching investigation. But for 

 the accurate study of nature we require a surer and more potent 

 instrument." 3 It is a remarkable fact, however, that in much recent 

 work (e.g. in the statistical work of idealist thinkers) it is maintained, 

 or at least implied, that the method of simple enumeration is the 

 only means by which correct (and, therefore, scientific) results can 

 be ensured. 



578. But, after I have learned by such enumeration that real 

 things have properties that vary in kind and degree and that 

 certain uniformities exist in nature, I have data that enable me to 

 think in a new way. I can now say to myself, "Ifit is true that 

 real bodies exist and have properties which bring them into rela- 

 tion with one another in definite ways, and z/it is true that certain 

 uniformities run through nature, then given certain conditions, 

 even combinations of conditions of which I have no previous 

 experience, certain results must follow, and can be thought of by 

 me even when I have had, and can have had no previous experience 

 of them. When I think thus, I think in terms of cause and effect, 

 and have passed from the notion of invariable to that of necessary 

 succession. The latter is not identical with the former ; it is a 

 superstructure reared on it. 



579. Thus, after I have acquired through experience definite 

 ideas of plane surfaces and of lines which are straight, perpen- 

 dicular, and parallel, I am able to pass the bounds of direct 

 experience and declare that straight lines, on the same plane 

 surface and perpendicular to another straight line, will never meet, 



1 Op. cit., Bk. III., chap, iii., 2. * Bacon, Novum Organon, i. 105. 



3 J. S. Mill, Logic, Bk. III., chap, iii., 2. 



