THE UNITY OF SCIENCE 23 



important generalizations in his own province either by es- 

 sentially distinct and independent hypotheses or by independ- 

 ent and laborious inductions concerning the unique character- 

 istics of the group of phenomena with which he was con- 

 cerned. A certain very general kinship in methods of pro- 

 cedure doubtless ran through all science ; but the unity of 

 knowledge and the complete logical continuity of scientific 

 explanation remained rather a platonic ideal than a serviceable 

 working principle in the advancement of learning. Talk 

 about it was left largely to the philosophers, especially the 

 philosophers of the more materialistic sort. The special 

 scientist in his hours of ease usually listened to this talk with 

 a good deal of complacency and a certain pious sense of edifi- 

 cation ; but he made small application of it to his serious 

 affairs. For his real interests he was satisfied to busy himself 

 in cultivating his private garden. 



This, I suppose, will be recognized as a fair description 

 of the average state of science, and the average state of mind 

 of the scientific investigator, during most of the eighteenth 

 and nineteenth centuries. It would not be very wide of the 

 mark as a characterization of the actual practical attitude of 

 most men of science of the present time. But many things 

 have happened during the past century, within the limits of 

 the special sciences themselves, to bring the ideal of unifica- 

 tion, or at least of a real rapprochement between contiguous 

 provinces of knowledge, more sharply to the fore. As in- 

 quiry progressed, it appeared that the problems of one study 

 were not so distinct from those of another, nor its phenomena 

 so unique and qualitatively irreducible, as they had for a time 

 appeared. The apparent ultimate diversities of different 

 groups of phenomena, though hardly eliminated, were cer- 

 tainly diminished in number. Facts that for a long time had 

 stood as disconnected have been found to have common de- 

 nominators with other facts ; in particular, certain definite dis- 

 coveries have been made which have seemed to make it pos- 

 sible to apprehend the sheer qualitative differences subsisting 



