78 
without the substance of the atom. As regards size or 
bulk, an atom is the smallest and simplest subject or vehicle 
of conatus ; but I think it possible to show that there are 
simple subjects of enormous extent. Before proceeding to 
that part of the discussion, and for the sake of more clearly 
illustrating the meaning of what I have to say, I would 
observe that all the visible subjects of nature are more or 
^ess compounds of conatus, that is to say, many kinds or 
intensities of force and their subjects exist in one subject, 
yet in that subject there is one conatus that controls the 
whole, and makes out of many a unit. This all-pervading 
conatus I would call the simplest, because the most univer- 
sal, and therefore, relatively, a conatus and subject of enor- 
mous extent. Now, every element or atom of which a tree 
is composed has its own conatus and its own subject. To 
suppose that these respective and differing intensities of 
conatus and their subjects are annihilated during the time 
that they are making up a tree is to suppose the annihila- 
tion of the tree whilst it exists. But as all these various 
forces make up but one subject, it is clear that there must 
be one conatus that controls the whole, and which makes 
all the other forces yield it service. This whole subject 
now becomes the vehicle for the all-governing conatus, be- 
cause in its government it makes up of all the other forces 
and their subjects what we call in this illustration a tree. 
And we know nothing of the all-pervading conatus of a tree 
excepting as it manifests itself in the effects which its sub- 
ject produces. Nor could all the conatus that make a 
tree from within subsist as a tree without the reaction of 
conatus from without, that is, from atmospheric air, &c # 
Hence, if there be no vehicle or subject there is no conatus, 
and if there be a conatus there must be a vehicle or subject 
and if there be a subject there must be action and reaction. 
All the subjects of nature afford an illustration of what I 
have called the government of compound conatus by an alb 
