APPENDIX G 277 



hinder or condition its existence, and accordingly, if it be pos- 

 sible, it must exist. The value of Leibniz's argument depends 

 on the worth of the distinction he makes between ( possible ' 

 and ' compossible,' that is to say between a metaphysical or 

 absolute necessity and a moral or inclining necessity. How 

 are these two kinds of necessity related to one another ? It is 

 hardly a satisfactory solution of the opposition between them 

 to refer the one to the understanding and the other to the 

 will of God. We have here again the fundamental weakness 

 of Leibniz's philosophy, the uncertainty of the relation between 

 the principle of contradiction and that of sufficient reason. 



Kant rejects the whole argument as a paralogism, on the 

 ground that ' existence ' can never be a predicate, that is to 

 say, that we are never justified logically in passing from a 

 mere idea to the existence of its content. (See Critique of 

 Pure Reason, Rosenkranz, ii. 462 ; Hartenstein, ii. 456 ; Meikle- 

 john's Tr., 364.) It is true that we can never pass from a mere 

 idea to the existence of its content ; but to adduce this as an 

 argument here is to beg the question. For a mere idea is an 

 idea of that which may be non-existent ; while the idea of 

 a necessary being is the idea of that which cannot be non- 

 existent. Gaunilo in his Liber pro insipiente, anticipates the 

 objection of Kant, and to this Anselm replied in his Liber 

 apologeticus contra respondentem pro insipiente, saying, among 

 other things : * Let us assume that the Summum cogitabile 

 need not exist merely because it is thought. Mark the con- 

 sequence. That which can be thought without really existing 

 would not, if it did exist, be the summum cogitabile ; so that, 

 by the hypothesis, the summum cogitabile is and is not the 

 summum cogitabile, which is in the last degree absurd ' (Rigg's 

 St. Anselm of Canterbury, p. 71. See the whole of his chap. v). 

 Cf. Introduction, Part iv. p. 173. 



