144 THE SCIENCE OF LOGIC 



Apart, however, from the question of the origin of such con 

 ceptions, there are undoubtedly in our minds the tendencies to 

 which we have referred. They have been crystallized in the 

 course of time by philosophers into maxims such as that known 

 as &quot;Occam s 1 razor&quot;: Entia non sunt multiplicanda praeter 

 necessitate, which may be interpreted as affirming &quot; a presump 

 tion in favour of theories which require the smallest number of 

 ultimate principles,&quot; 2 for example, &quot;in favour of the derivation 

 of the chemical element from some common source, or of the 

 reduction of the laws of gravitation, electricity, light and heat to 

 a common basis&quot;. 3 It simply voices the innate yearning of the 

 human intellect to unify, as far as possible, the manifold of experi 

 ence. The same sort of prepossession is also expressed in the 

 maxims: &quot;Simplex indicium veri&quot; and &quot; Natura non abundat 

 superftuis sed delectatur paucissimis &quot;. In other words, we are 

 prompted to regard the simplicity of a conception or hypothesis 

 as an index of its truth. We give our preference to the simplest 

 of a number of equally probable alternative explanations, not 

 merely from the motive of practical convenience, but with a feel 

 ing that because the actual universe is rational the simplest theory 

 of things ought to be the true one. 4 



We can hardly say that the guiding principles embodied in 

 such maxims are &quot; preconceived ideas &quot; pure and simple. Rather, 

 they are gradually moulded in our minds by our progressive 

 understanding of the universe. But further reflection will teach 

 us that, if followed blindly and unquestioningly, they may mislead 

 us. It would be unwise to demand simplicity in hypotheses 

 merely on the ground that Nature always acts in the simplest way. 

 &quot;Even so,&quot; writes M. Rabier, 6 &quot;to determine a priori what are 

 the simplest ways possible , we should know what is the minimum 

 of complication necessary. And since we have no data to deter 

 mine the latter, it is quite useless to attempt an a priori solution 

 of the former. . . . The idea of the simplicity of nature s 

 methods, without its indispensable corrective, viz. a realization 



1 Occam was one of the later mediaeval Scholastics. He lived in the first half of 

 the fourteenth century. C/. DE WULF, History of Medieval Philosophy, pp. 420-5. 



a JOSEPH, of. cit., p. 470. 3 ibid. 



4 Hence, for instance, the ratio of the inverse square in the law of gravitation 

 is regarded as the true ratio, though some more complex ratio might yield results 

 deviating so slightly from those of the former as to escape detection in our actual 

 measurements and observations. C/. JOSEPH, ibid. 



*Logique, p. 239. 



