THE EVOLUTION OF SCIENTIFIC THEORIES 277 



at an earlier stage it is difficult to get a distinctive pattern growth or 

 pattern value started. Not infrequently, when a pattern has attained 

 realization or reached saturation, its limitations appear to be felt and 

 efforts are made to alter or enlarge it. If these efforts take the form of 

 a pause in activity, there may be a reconstitution of energy and direc- 

 tion, . . . growth is renewed along somewhat new and broader lines. 



Infancy and youth. As first born, a scientific theory is most often 

 comparatively crude in construction. Taton remarks: 



The innovator who reverses a theory and tries to replace it by another 

 cannot hope to produce the most unimpeachable arguments and the 

 most convincing demonstrations. The effort to rebuild an entire edi- 

 fice, patiently constructed and consolidated by the work of many gen- 

 erations of scientists and by long tradition, is so immense that it is 

 rare for one man to accomplish this transformation definitely by 

 himself. 



The new theory will reflect its creator's novel insights, but also his 

 limitations— in part produced by his inability wholly to free himself 

 of the older pattern of thought in which he was reared. The con- 

 ceptual structure he creates will ordinarily be blemished by sub- 

 stantial inconsistencies, irrelevancies, superfluities, exclusions, or the 

 like. 



Advances in observation and experiment may help to bring about 

 improvement, but the major refinements of the new theoretic idiom 

 will be made by eliminating conceptual flaws its creator may have 

 been wholly unable to recognize, much less to repair. Thus Kepler's 

 reconstruction of the Copernican theory— in which all epicycles are 

 eliminated through the introduction of elliptic orbits— demanded a 

 freedom from obsession with perfect circular motion that Coper- 

 nicus himself probably could not have approved, and never attained. 

 Newton's Principia oflFers his system in a highly developed form, but 

 an error in the calculation of the lunar orbit remains to be corrected 

 by Clairaut; and approximately a century elapses before Laplace 

 gives Newton's system its definitive and most powerful development. 



Dalton's own conception of the chemical atomic theory was so 

 fundamentally defective that he completely failed to realize the im- 

 mense value to that theory of the discoveries of Gay-Lussac and the 

 suggestions of Avogadro. An adequate foundation for the theory was 

 not constructed until 50 years after Dalton's work, and today we en- 



