CONCLUSION 115 



able in the textbooks of psychology as in those of physics, and the 

 extent to which this may occur will depend entirely upon the extent 

 to which theorist and experimenter cooperate in their efforts to bring 

 it about. On the other hand, it is neither to be expected nor to be 

 desired that quantitative formulations can in any sense represent all 

 of the complexities of any psychological process, or a fortiori, the 

 true "inwardness" of conscious life. 



If this brief summary of theoretical developments to date leaves 

 the reader with a feeling of incompleteness, as of a story interrupted 

 before it is well under way, this is only as it should be. For the authors 

 the hardest task in presenting each topic has been to leave it incom- 

 plete rather than to postpone the writing of it while pursuing it fur- 

 ther. In general, we have summarized each topic as far as it has yet 

 been developed. On the other hand, we have had to leave out many 

 things that might have been included. To mention a few of these, 

 Landahl (1940) has given an interpretation of factor-loadings in 

 terms of time-scores; and he has suggested (Landahl, 1939) a pos- 

 sible solution of the "bottle-neck" problem of the visual pathway; 

 Coombs (1941) has discussed the galvanic skin response; Household- 

 er (1939) has discussed a mechanism for a certain Gestalt-phenome- 

 non; Householder and Amelotti (1938) have outlined a theory of the 

 delay in the conditioned reflex. Rashevsky (1938) has outlined sev- 

 eral theories of rational thinking. Pitts (1943) has given a formal 

 theory of learning and conditioning, and Lettvin and Pitts (1943) 

 have developed a formal theory of certain psychotic states. While 

 neither of these last two theories provides an explicit neural mech- 

 anism, both carry, by implication, fairly clear suggestions for these 

 and their construction is in progress. Finally, Rashevsky's work on 

 visual aesthetics, referred to in the introduction, is now the subject 

 of extensive experimental test with very satisfactory preliminary re- 

 sults. Only part of this theory has been published as yet. 



While Rashevsky is actively developing his theory of aesthetics, 

 additional work is now under way and soon to be published dealing 

 with shock and certain psychotic mechanisms, with apparent move- 

 ment, and with further elaboration of the theory of color-vision. 



But all this together— the work accomplished and the work under 

 way— touches only a very small part of the field of psychology, and 

 the theories as we have them now represent at best a number of pre- 

 liminary attempts, many of them still untested. We do not present 

 them as finished products. Quite the contrary, no one would be more 

 surprised — or disappointed !— than the authors if a decade hence does 

 not find every one of these theories considerably modified if not 

 wholly discarded for a better. 



