42 PHILOSOPHICAL SOCIETY OF WASHINGTON. 
establishment of the Newtonian philosophy, and the discovery of 
the discrete character of substance. 
In point of fact, experience would point to extreme porosity or 
discreteness as characteristic of substance, rather than to its oppo- 
site—perfect continuity. The infinite divisibility of space has 
nothing in the world to do with the question, though this is a con- 
fusion often fallen into. On the contrary, there is an infinite dis- 
tinction between the infinitesimal discrete units of substance, occu- 
pying extension by their interactivity, and the passive infinitesimal 
resolvability of space continuity. This is the antipodean difference 
between the Epicurean and the Cartesian conceptions; the former 
admitting of the operations of force, the free exhibition of motion, 
the organization of material phenomena, which are phenomena of 
mobility; the latter constituting a plenum, with only ideal divisions, 
and phenomenally as necessarily barren a negation as space itself. 
Substance is purely experiential. In its essence it is still incom- 
prehensible, because experience has not yet reached down to those 
recesses. We know nothing of substance except by its manifesta- 
tions. These manifestations are cognized by us through sense im- 
pressions, weighed, compared, adjusted, and analyzed in the mys- 
terious alembic of the mind. First impressions have enormous 
predominance, and are intensified by heredity of cerebral predis- 
position and function. 
We cognize substance only in bulk by direct perception, and 
these vast aggregations stand in thought for matter. A drop of 
water contains incomparably more molecules than the ocean con- 
tains drops; a grain of sand more particles than the earth contains 
grains; and it is this vast mesh of complicated forces that forms 
the integrated concept of matter to our apprehension. The child, 
before he can walk, encounters obstacles to movement, reaction to 
his every muscular effort, of equal measure to his own; and thus 
his first and profoundest convictions of objective existence are asso- 
ciated with resistance, opposition, repulsion. This impression of 
matter is so early that it remains with us as its most natural and 
obvious characteristic. 
The idea of weight is also one of the earliest experiences. This 
idea would not be conceivable to a denizen of the deep sea, for 
our first ancestor who emerged from the water gained theexperience 
at the cost of great struggle and enterprise. By the natural devel- 
