XXXIV PHILOSOPHICAL SOCIETY OF WASHINGTON. 
doctrine reappears under one form or another in every dualistic 
conception of matter and mind—now in the purple light of Plato’s 
imperial fancy, and now in the pallid shades of that metaphysical 
theology which, in the days of Origen and St. Augustine, arrayed 
the doctors of the Church into opposing schools on the great ques- 
tion of Traducianism or Creationism. 
In whatever way the Atomic Philosophy was begotten in’ the 
Greek mind, we know that on its emergence it was subjected to 
the solvents of philosophical criticism, and underwent a variety 
of transformations. So soon as we come within the lines of 
definite history we find a bifurcation of ideas between such typical 
teachers as Anaxagoras on the one hand, and Leucippus and 
Democritus on the other. This dissidence of opinions had regard 
to the nature and the constitution of the ultimate atoms which 
compose the substance of matter. The doctrine of Anaxagoras 
was qualitative; the doctrine of Democritus was quantitative. 
Anaxagoras held that the atoms which compose the physical Uni- 
verse in its fleeting forms, and at the same time in its enduring 
substance, are eternally differentiated in kinds, and that it was by 
the collocation and adhesion of like parts—of bony atoms to make 
bone, of fleshy atoms to make flesh, of stony atoms to make stones 
—that the actual varieties of body in the Universe were built up. 
This is the famous doctrine of Homeomeria which fares so ill in 
the spiritual philosophy of Plato, and which fares no better in the 
materialistic philosophy of Lucretius. Aristotle tells us that 
Anaxagoras was driven to adopt this hypothesis in order to relieve 
the doctrine of atoms at the points where the heaviest stress and 
tightest pinch seemed to be laid upon it by the dogma De nthilo 
nihil fit; for how else, said Anaxagoras, could we account for the 
existing varieties of matter unless there be an original and eternal 
variety in its constituent elements? 
Democritus simplified the theory of atoms by giving to it a purely 
mechanical reduction. Conceiving atoms to be invisible by reason 
of their smallness, he at the same time conceived them to be indi- 
visible, not as mathematically considered, but as physically consid- 
ered; and while holding them to be infinite in number and infinite 
in their-shapes, he at the same time held that they differed not at 
all in inherent quality, but simply in their shapes, sizes,,situations, 
and motions, and that hence it was by the different combination of 
