238 THE SCIENCE OF LOGIC 



too, the &quot; discovery of laws&quot; according to which natural agencies 

 co-operate in maintaining the order of nature, is, eo ipso, the 

 &quot; demonstration of properties &quot; which characterize those agencies. 

 Mr. Joseph points to what is rather a contrast of terminology than 

 a conflict of views when he says l &quot; Science seeks to-day to 

 establish for the most part what are called laws of nature ; 

 and these are generally answers rather to the question Under 

 what conditions do such and such a change take place ? than 

 to the question What is the definition of such and such a sub 

 ject ? or What are its essential attributes ? &quot; He seems to 

 think that the contrast lies in the different manner of putting the 

 problems : &quot; though it is possible to bring many scientific in 

 vestigations to-day under one or other of the types of question 

 which Aristotle says we inquire into, yet looking to his examples, 

 one must confess that (as is natural) he puts the problems of 

 science to himself in a very different manner from that in which 

 scientific men put them now &quot;. 2 But the difference lies rather 

 in the nature and scope of the problems themselves: the pro 

 gress of discovery since the days of Aristotle has inevitably given 

 rise to scientific problems of which he could not have had even 

 a suspicion. And Mr. Joseph admits that it is &quot; more in respect 

 of the problems to be answered than of the logical character of 

 the reasoning by which we must prove our answers to them, that 

 Aristotle s views (as represented in the Topics} are antiquated&quot;. 3 



It will serve to bring out more clearly the nature of scientific 

 explanation, if we contrast it briefly with the process of Illustra 

 tion, which sometimes gets the name of &quot; Popular Explanation &quot;. 

 While the former enables us to understand things by what is 

 naturally prior to them, the latter helps us to take in and realize 

 new facts by what is prior in our experience to these latter. All 

 progress in knowledge must be from the better known to the less 

 known : ignotum per ignotius is not an aid to knowledge, but an 

 impediment. 



Since, however, explanatory principles are more remote from 

 experience than familiar facts, we often have to try to take in 



1 op. cit., pp. 358-9. 



a ibid., p. 359, n. i. He refers to Anal. Post., ii., c. i. i : rk ^rovfj.fvd ianv laa. rbv 

 aptGnbv 8crairep &ri&amp;lt;TT&amp;lt;/uefla. frjToC/i 5i rtrrapa, rb Sri, rb $i6ri, fl &amp;lt;t&amp;lt;TTt, rl fffrtv. 

 From the context these four would appear to be two alternative ways of asking (i) 

 whether a thing is, and (2) why it is. In other words, it distinguishes two kinds of 

 proof, namely, proof of fact, and causal proof or strict demonstration. Cf. 254. 



3 ibid. 



