192 THE PRINCIPLES OF SCIENCE 



We seek to understand the characteristics of hchens by viewing 

 them as aggregates of algae and fungi, which parts we study in 

 abstraction from each other. But of course the properties of a hchen 

 are not simply the sum or average of alga and fungus properties. 

 There is a co-operative phenomenon to which, as usual, we give a 

 special name: symbiosis. Symbiosis is not something new and mys- 

 terious; it symbolizes just those interactions originally neglected. In 

 pharmacy we come to consider ( as "synergism" ) the special features 

 of the joint action of two drugs originally considered singly; in medi- 

 cine to consider (as "psychosomatic") phenomena that seem to in- 

 volve the interaction of the two polarities— mind and body— physi- 

 cians ordinarily treat in complete abstraction from one another. 



A very few modern investigators have joined Driesch in maintain- 

 ing that, by its approach through "parts," science condemns itself to 

 eternal ignorance of wholes clearly more than any sum of parts. 

 Whatever superficial plausibility this argument may present, I 

 hold it fundamentally specious. Given "parts," often the able scientist 

 can conceive wholes! What could be more outrageously arbitrary 

 than the parts into which the embryologist's microtome cleaves his 

 specimen? But from hundreds of these flat "sections" the skilled 

 embryologist recreates in thought the three-dimensional totality of 

 the intact embryo. Far more than that, by carrying through the 

 same operation with a whole series of embryos of different age, he 

 at last grasps the entire course of development of the single intact 

 embryo. Behold the completed superposition of parts that could 

 scarcely be more "unnatural"! 



I find no basis whatever for the happy confidence with which ob- 

 scurantists predict the defeat of science in the face of "the great prob- 

 lem of life." The life of an organism we seek to comprehend in terms 

 of parts: anatomical, histological, and molecular. But no scientist is 

 simple enough to suppose that the organism can in thought be re- 

 constituted without due attention to the interactions of these parts 

 on macroscopic, microscopic, and molecular levels. We hope ulti- 

 mately to find "life" emergent from chemical systems the components 

 of which are not alive in any meaningful sense; this alone could for 

 us represent a rational explanation. Far from being an annoyance or 

 disaster, the co-operative phenomena that make superposition differ- 

 ent from summation are, in fact, the essential presupposition of every 

 attempt to explain the qualities of wholes. 



