Laws and Hypotheses for Behavior 267 
in the laws of exercise and effect. Jennings has formulated 
as an adequate account of learning the law that: ‘“‘When 
a certain physiological state has been resolved, through 
the continued action of an external agent, or otherwise, 
into a second physiological state, this resolution becomes 
easier, so that in course of time it takes place quickly and 
spontaneously ” (‘Behavior of the Lower Organisms,’ p. 289). 
“The law may be expressed briefly as follows: — The 
resolution of one physiological state into another becomes 
easier and more rapid after it has taken place a number of 
times. | Hence the behavior primarily characteristic for 
the second state comes to follow immediately upon the first 
state. The operations of this law are, of course, seen on 
a vast scale in higher organisms in the phenomena which 
we commonly call memory, association, habit formation 
and learning ” (bid., p. 291). This law may be expressed 
conveniently as a tendency of a series of states 
A->B->C7->D 
to become A~>D 
or A>B!>C!+>D 
B! and C! being states B and C passed rapidly and in a 
modified way so that they do not result in a reaction but 
are resolved directly into D. 
If Professor Jennings had applied to this law the same 
rigorous analysis which he has so successfully employed 
elsewhere, he would have found that it could be potent 
to cause learning only if supplemented by the law of effect 
and then only for a fraction of learning. 
For, the situations being the same, the state A cannot 
produce, at one time, now B and, at another time, abbrevi- 
ated, rudimentary B! instead of B. If A with S produces B 
once, it must always. If D orarudimentary B? is produced, 
there must be something other than A; A must itself have 
