834 president's address. 



"which claims an empirical freedom of will amid the strife of 

 motives," and as it is impossible " to save for this self even the 

 power of directing attention on one motive rather than another," 

 so, whenever the organism is regarded as a vehicle of energy, it is 

 vain to aim at vindicating the idea of final cause by claiming for 

 it any empirical power of determining the distribution of that 

 energy for ends or purposes. 



In the same able essa}' from which I have quoted the reference 

 to purposive distribution of energy, allusion is made to the well- 

 known phenomena manifested in the regeneration of the ampu- 

 tated limb of a newt. After summarising the process by which 

 the bud of embr3'^onic tissue goes on to re-form all the tissues of 

 the lost limb, bone, muscle, nerve, itc, the writer proceeds : — 

 " Every cell performs its appropriate duty until the whole busi- 

 ness is accurately finished without fail. Is it conceivable that 

 each of the thousands of separately existing cells concerned in 

 the process should have a mechanism within it which would cause 

 it in spite of all obstacles to take up the position and undergo the 

 modification requisite for the proper performance of its work in 

 the newly developed hand? Or is it conceivable that mechanical 

 pressure of any kind should cause the bud to grow into a 

 perfect hand 1 The alternative hypothesis is that each cell is 

 determined directly in its action simply by what it has to do in 

 order that the vital activity of the newt may be restored to its 

 normal condition." 



Now to my mind it is not only not impossible but it is almost 

 imperative that we should conceive just such mechanical arrange- 

 ments as are here assumed to be out of the question. Without 

 such presupposed mechanism no conception of detailed sequences 

 of events could be formed and the entire natural process would 

 have to be regarded as physicallj^ unintelligible. But some 

 definite chain of physical events in such a case there nutsf be ; 

 and each event must have its physical antecedents and conditions 

 which must almost necessarily be embodied in some sort of 

 structural mechanism. What that mechanism is is of course 

 precisely the kind of question which it is the function of Natural 



