98 INTRODUCTION 



abstract and imperfect thought (i.e. in 'sense' or 

 ' imagination ' as distinct from thought proper) we are 

 presented with the phenomena of things variously 

 grouped in space, and these groups, qua groups, are 

 materia secunda l . 



Phenomena bene fundata. 



As materia secunda is always a mere aggregate, while 

 yet every aggregate pre-supposes as its reality an in- 

 divisible simple substance or soul, such aggregates or 

 groups of things, together with their powers, acts, and 

 affections, are sometimes described by Leibniz as well- 

 founded phenomena (phenomena bene fundata). They are 



1 Cf. Lettre a Arnauld (1686) (G. ii. 75, 76) : ' In my opinion, our 

 body in itself (setting aside the soul), or the Cadaver, can be called 

 one substance only by a wrong use of terms, like a machine or 

 a heap of stones, which are only beings by aggregation ; for regular 

 or irregular arrangement has nothing to do with unity of sub- 

 stance. ... I hold that a marble pavement is probably only 

 like a heap of stones, and thus cannot pass for only one sub- 

 stance, but is a collection of several. For suppose there are two 

 stones for example, the diamond of the Grand Duke and that of 

 the Great Mogul we might give them both, in respect of their 

 value, one and the same collective name, and we might say that 

 they are one pair of diamonds, although they are actually far 

 distant from one another. But it will not be said that these 

 diamonds compose one substance. Now more or less make no 

 difference here. Accordingly, if we bring them nearer one 

 another, and even make them touch one another, they will be 

 none the more united in substance ; and although, after they had 

 been brought into contact, we were to join to them some other 

 body in such a way as to prevent them separating again for 

 instance, if we were to set them in one ring all that would make 

 of them only what is called unum per accidens. For it is as by 

 accident that they are compelled to share in the same motion. 

 I hold then that a marble pavement is not one concrete [accomplie~\ 

 substance, any more than would be the water of a pond with all 

 the fish it holds, even although all the water and the fish were 

 frozen together ; or than a flock of sheep, in which the sheep 

 should be supposed to be so bound together that they could only 

 walk in step, and that one could not be touched without all the 

 others crying out. There would be as much difference between 

 a substance and such a being as between a man and a community, 

 like a people, army, society or college, which are moral beings and 

 in which there is something imaginary and created by our mind. 

 Unity of substance requires an indivisible and naturally inde- 

 structible concrete [accomplie~] being, since the notion of such a 

 being includes all that is ever to happen to it.' 



