276 THE MONADOLOGY 



God, which contains all simple forms taken absolutely, is 

 possible. Now we have proved above that God is, provided 

 He is possible. Therefore He exists.' (G. iv. 294 and 296.) 

 Thus Leibniz, as he himself says (G. iv. 405), holds a middle 

 position between those who regard the Cartesian proof as a 

 sophism and those who say that it is a complete demonstra- 

 tion. God's existence, for Leibniz, follows immediately from 

 His possibility, for all real possibility includes a tendency to 

 existence, and there can be nothing to hinder this tendency in 

 a being supposed to be perfect. In the Reponses aux Deuxiemes 

 Objections, Descartes maintains the possibility of the idea of 

 a most perfect being. But he does not make this a prominent 

 or essential part of his proof, as Leibniz does. Cf. Descartes, 

 Meditation 5 ; Prindpia Philosophise, Part i. 14 sqq. 



In the Animadversiones in partem generalem Principiorum 

 Cartesianorum (1692) (G. iv. 359) Leibniz suggests that the 

 argument might be simplified by omitting the reference to 

 'perfection,' and merely saying 'a necessary Being exists or 

 a Being whose essence is existence, or Being in itself [ens a se] 

 exists as is evident from the terms. Now God is such a being 

 (from the definition of God), therefore God exists. This argu- 

 ment holds if it be granted that a necessary being is possible 

 and does not involve a contradiction, or, what is the same 

 thing, that the essence from which existence follows is possible.' 

 Elsewhere (E. 177 b ; G. iv. 406) Leibniz points out that 'those 

 who hold that from notions, ideas, definitions or possible 

 essences alone we can never infer actual existence . . . deny the 

 possibility of being in itself [ens a se]. But ' if being in itself 

 is impossible, all beings through another ' [entia ab alio] ' are 

 also impossible, since indeed they are only through being in 

 itself: thus nothing can exist.' 



As against Spinoza, Leibniz's argument would be that not 

 all that is possible is actual, but only the compossible or com- 

 patible. There are unrealized ' possibles,' essences which do 

 not involve existence, and consequently the necessary being, 

 whose essence involves existence, is not the all, but is some- 

 thing distinct from the world of created things. The essence 

 of a created being does not involve its existence, because it is 

 limited, and thus its existence depends upon its .' fitting into ' 

 other essences so as to constitute, along with them, the best 

 possible world. But the essence of a necessary being involves 

 its existence because it is unlimited. There is nothing to 



