LIFE 333 



of metaphysic dogma. If the biologist gives us an 

 accurate account of the development of the ovum and 

 then remarks that the changes are due to " forces resident 

 in the &^%" he certainly cannot mean that the chemist 

 and physicist are capable of explaining what has taken 

 place. He probably considers that the conceptual short- 

 hand of chemistry and physics would suffice to describe 

 what he has himself described in other language. If we 

 always remember that the physicist's fundamental con- 

 ception of change of motion is that the change of motion 

 of one particle is associated with its position relative to 

 other particles, and that force is a certain convenient 

 measure of this change, then, I think, we shall be in a 

 safer position to interpret clearly the numerous biological 

 statements which involve an appeal to the conception of 

 force. We must in each case ask what individual thing 

 it is which is conceptualised as moving, what is the field 

 with regard to which it is considered as moving, and how 

 its motion is conceived to be measured. When we have 

 completed this investigation, then, we shall be better able 

 to appreciate the real substance which lies beneath the 

 metaphysical clothing with which biological, like physical, 

 statements are too often draped.^ 



Admitting, therefore, that our object in biology is 

 identical with that in physics, namely, to describe the 

 widest ranges of phenomena in the briefest possible 

 formulae (p. 97), we see that the biologist cannot throw 

 back life for an explanation on physics. Whether he can 

 hope to describe life in physical shorthand is a point to 

 which we shall return a little later. If we look upon 

 biology as a conceptual description of organic phenomena, 



1 We are told, for example, that "force is always bound up with matter," 

 that too small an "amount of matter" may be present to exercise a "con- 

 trolling agency " over the development of the embryo, and when we seek 

 to associate this " amount of matter " with some definite group of sense- 

 impressions we find that no perceptual equivalent has been found for it. 

 What the biologist is clearly striving to do is to form a conceptual model of 

 the embryo by aid of the relative motions of the parts of a geometrical or 

 rather kinetic structure (p. 315), but it is difficult to reach his ideas beneath 

 the metaphysical language in which he projects matter, force, and germ-plasm 

 into real substrata of sense-impression (see Weismann : Essays on Heredity, 

 pp. 226-7). 



