158 INTRODUCTION 



guesses ; but it must consist in tracing the necessary 

 connexions of things or finding definitely measurable 

 relations between them connexions and relations which 

 the understanding can clearly grasp. That is, in brief, 

 the mechanical view of what explanation ought to be, 

 as the Cartesians held it in opposition to the Scholastics. 



Now Leibniz, as we have seen, is not so exclusively 

 enamoured of the clear and distinct as Descartes was. 

 He thinks Descartes has gone too far in the zeal of his 

 reformation. Doubtless the Scholastics were guilty of 

 gross absurdities, but if we are to be satisfied with no 

 explanation which is not absolutely perfect in its intelli- 

 gibility, we shall have to do without explanations of most 

 things, and our science will perforce be very abstract and 

 very limited. For to be perfectly intelligible or clear and 

 distinct in the Cartesian sense, an explanation must either 

 be a self-evident truth or must be logically reducible to 

 such a truth. And Leibniz maintains that, while ideas 

 or abstractions (' possible ' things) may be capable of such 

 explanation as this, it is impossible so thoroughly to 

 explain any actually existing finite thing or phenomenon. 

 We may ' clearly and distinctly ' explain how such a 

 thing is possible ; we cannot * clearly and distinctly ' 

 explain why it exists. No absolute reason can be given 

 for its existence ; we must be content with a sufficient 

 reason. An examination of the measurable relations or 

 connexions of things does not yield an exhaustive account 

 of their nature, and accordingly, while such an exam- 

 ination is valuable so far as it goes, it requires to be 

 supplemented by other considerations. The infinite 

 complexity of things makes a perfect analysis impossible, 

 and consequently, if we confine ourselves to a strictly 

 mathematical method, our science must remain a science 

 of abstractions and not of actual things as they exist. 



Leibniz, then, admits the value of the mechanical view 

 as regards phenomena, considered in abstraction from the 

 realities of which they are the phenomena, but he returns 



