114 STUDIES IN GENERAL PHYSIOLOGY 
were formerly believed to be determined by the “will” of 
the animal, the authors are still dissatisfied. They did not 
doubt that ultimately a physical solution of the question 
would be found, but they expected something more sublime, 
something which is more closely related to the mysticism of 
the ganglion cells. Of course, our knowledge of the process 
is not exhausted when it is proved that the direction of the 
rays of light prescribes the direction of the progressive move- 
ments of Hamatococcus swarm-spores or the Nauplii of 
Balanus; just as little as the knowledge of the chemical 
effects of light is today exhausted. Yet no one will say 
that “instinct” is the determining circumstance in these 
physical phenomena. 
6. Just as the past generation of physiologists felt it 
to be a handicap that instead of looking for the causes of 
life-phenomena, investigators were satisfied with the phrase, 
“The vital force is the cause,” so it is a handicap to us that 
within the more limited sphere of the so-called psychic life- 
phenomena the influence of this scholastic method of think- 
ing has survived to the present time. The handicap lies in 
the fact, that if one says that “instinct” or “will” deter- 
mines a motion, the true problem involved is ignored or 
concealed. This true problem is the analysis of the circum- 
stances which in each case detérmine unequivocally the 
“voluntary” movements of an animal. It was the object of 
this paper to point out that we must endeavor to solve this 
problem with as little concern for ‘‘instinct” and “will” as 
for ‘vital force.” 
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