i] CHEMICAL EMBRYOLOGY 31 



No doubt the most powerful solvent of vitalism will turn out to 

 be the set of changes now taking place in physics. It is as yet too 

 early to describe very definitely the effects of these, and several 

 modern writers on the subject are rather free in their use of the word 

 "mysticism", but it is at any rate clear that physicists are coming to 

 see more clearly than before the impHcations and the limitations of 

 the study of the metrical aspects of the world, which is what science is. 

 Behind these sets of numbers and quantities the background of the 

 world is enigmatic, and Heisenberg's Principle of Indeterminacy 

 indicates that extreme accuracy can only be obtained at a cost. 

 Again, the abandonment of the model in physics is a highly important 

 step, and physics seems to have reached a point at which there is no 

 analogy in our everyday experience for the phenomena with which 

 it is dealing, so that we cannot even picture in ordinary words what 

 is happening. Eddington, in his great work The Nature of the Physical 

 World, also shows that physics no longer speaks of the motion of 

 every individual particle in the universe being rigidly determined but 

 rather of the relative probabilities of its motions, i.e. the odds on 

 them. If this funeral of Laplace's Calculator should turn out to 

 be enduring, a good deal of difficulty may vanish from the biological 

 sphere. But I should prefer to leave the working out of these possi- 

 bilities to those better qualified than myself, and to suggest simply 

 that if the mechanical theory of the world is being reconstructed by 

 modern physics, there may be a widespread sapping of the force of 

 neo-vitaHstic contentions in the near future. I have often thought 

 that neo-vitalists were thinkers whose religious sense had got into the 

 wrong place; unable to set up commonsense watertight compart- 

 ments on the one hand, or to work out a philosophy of the forms of 

 experience on the other, they brought the numinous into biology and 

 abused biophysics. The fundamental contention of the mechanists 

 always was that science and the scientific method were one and that 

 biology was complicated physics — this remains unaltered. But if 

 physics is more and more obviously throwing off the links which 

 bound it in the past to metaphysical materiahsm, and admitting 

 itself to be the study of the metrical aspects of the world, there will 

 be perhaps less excuse for the misplacement of the numinous, as it 

 might be called; and the affirmation that biology must be based 

 upon physics will cause less antagonism than in the past. In a word, 

 the vitaHsts wished to introduce mysticism at the wrong level; the right 



