I] CHEMICAL EMBRYOLOGY 19 



conclusion of the thought of Bosanquet and Henderson was that, 

 though teleology was a conception which it was impossible to 

 do without, yet any limitation of it to, or special association of it 

 with, living organisms, was inadmissible. The question remained, 

 What has teleology to do with science? 



This point has been approached best by J. W. Jenkinson with his 

 usual clarity. "Those who uphold teleological doctrine", he said, 

 "seem to have fallen into a confusion between two different things, 

 the formal and the final cause. The material, efficient, and formal 

 causes, if we mean by the last the idea of the effect in the mind of a 

 sentient being, all precede in time the occurrence of the effect; and 

 this kind of teleology is not, as it is asserted to be, a doctrine of final, 

 but one of formal causes. The final cause stands for the use to which 

 an object is to be put, the effect it will produce, the function it will 

 perform, which obviously succeed in time the existence of the object 

 itself The final cause, then, cannot be taken as ever determining in 

 time the existence of the object itself, and is therefore a conception 

 which belongs not to science but to metaphysics. The only necessary 

 conditions of a phenomenon ascertainable by science are those 

 material and efficient causes which precede it." Or, as Streeter puts 

 it, "If there is purpose in nature, we ought not to expect science to 

 reveal it. Purpose is activity, the direction of which is determined 

 by an end, that is, by an apprehension of quality or value. But 

 quaUty cannot be measured, and therefore from its essential nature 

 it — and along with it purpose — lies outside the sphere of science". 

 Or, finally, to go straight to the fountain-head, "If I say", says 

 Kant, "that I must judge according to merely mechanical laws of 

 the possibility of all events in material nature and consequently of all 

 forms regarded as its products, I do not therefore say: they are 

 possible in this way alone. All that is impUed is: I must always 

 reflect on them according to the principle of the mere mechanism 

 of nature and consequently investigate this as far as I can ; because 

 unless this Ues at the basis of investigation there can be no proper 

 knowledge of nature at all". Purposiveness, in fact, is not a concep- 

 tion which interlocks with quantitative treatment; that mathematical 

 expression of relationships which is the ideal type of all science 

 has here nothing upon which to impinge, and the pulling force, 

 perpetually going on before, eludes and must always elude, if this 

 analysis is correct, the advancing web of mechanical explanation. 



