THE PRINCIPLES OF SCIENCE 175 



possess these qualities. If atoms are really to explain the origin of 

 color and smell of visible material bodies, then they cannot possess 

 properties like color and smell. 



But close to the beginning of the era of modern science we find the 

 same insight in Newton, though not in all of his contemporaries ( or 

 ours ) . Having in mind a further question ( What is responsible for the 

 cohesive strength of an "atomic hook"? ) , he remarks : 



The parts of all homogeneal hard bodies which fully touch one 

 another, stick together very strongly. And for explaining how this may 

 be, some have invented hooked atoms, which is begging the ques- 

 tion; . . . 



The qualities for us "explained" by a theory can only be those not 

 imputed to the primary entities of that theory. The greater their 

 penury— the fewer the qualities they possess— the more numerous 

 become the qualities rendered potentially explicable by the theory. 

 Any quality so explained is then shown comprehensibly emergent ( in 

 a sense presently to be examined) from the deportment in a context 

 of entities lacking precisely that quality. 



Evolutionary theories have in this respect immense explanatory 

 appeal. Carrying this line of thought to its extreme, we set out from 

 Gamow's concept of a qualitatively undiflFerentiated super-hot super- 

 dense plasma in which, some billions of years ago, a nuclear explosion 

 on a cosmic scale was followed by a physical evolution of elements. 

 That development he supposes followed (and completed) by an 

 astronomical evolution of galaxies, suns, planets, etc.; and that in 

 turn by such a geological evolution as has produced the varied topog- 

 raphy of our planet. Instructed by Oparin and others, we may then 

 conceive a chemical evolution, yielding moderately complex mole- 

 cules, and carrying on through some step(s) as yet unknown to the 

 production of one or more rudimentary forms of life. By a further 

 biological evolution we may, with Darwin, suppose higher animals 

 like ourselves produced, then to undergo a sociologic evolution, and 

 so on and on. 



In this chain of theories many links are at present little more than 

 speculations. But such an evolutionary development does propose a 

 potentially acceptable scientific explanation— conspicuously charac- 

 terized by the continual emergence of diverse qualities and com- 

 plexity from systems having fewer qualities and less complexity. 



