68 THE AIM AND ACHIEVEMENTS OF SCIENTIFIC METHOD. 



intelligible by means of concepts drawn from diverse fields 

 of experience already explored ; the choice of concept being 

 determined only partly by the actual Objective data, and for 

 the other part by psychological conditions.* Of course, it may 

 be maintained that there is really a question of facts at issue : 

 a purpose either does or does not lie at the back of the 

 phenomena. Here we are confronted by a difficulty which will 

 be considered at a later stage."f We may decline to discuss it 

 in the present connection on the ground that few thinkers, 

 if any, would regard the Objectivity of a purpose as capable of 

 proof except as a " residual phenomenon " after the application 

 of all possible physico-chemical explanations. It is not likely 

 that any biologists would maintain that this stage has actually 

 been reached. We may conclude then that the only considera- 

 tions which should interfere with the purely individual choice 

 of one type of interpretation over another are considerations, if 

 such can be arrived at, of the relative usefulness of particular 

 kinds of hypotheses at the particular stage of exploration of the 

 province of fact under discussion.^ 



24. 



From this point of view the opposition between " causal " 

 and "final" explanations appears in a new light. Both 

 " cause " (" Ursache ") and " end " or " purpose " (" Zweck ") are 

 concepts abstracted from definite experiential contexts. We 

 have maintained that any such concept may be used to make 

 Objective facts intelligible to an individual investigator : the 

 question as to the Objectivity of 'the cause or the purpose may 

 ultimately have to be decided in a given case, but at the 



* It is not implied, of course, that the selection of the Objective data 

 for interpretation is independent of these psychological conditions. 

 Bunge and Dr. Jennings, starting from different points of view, inevitably 

 deal with data of somewhat different characters. See p. 144. 



t Infra, Ch. V. 



j See, for example, Bieganski, Neo- Vitalismus in der moderne Biologie 

 (Ann. der Natur philosophic, IV, i). 



