Laws and Hypotheses for Behavior 247 
or less likelihood that the same current will be conducted 
from the former to the latter rather than to some other place. 
The strength or weakness of the connection is a condition 
of the synapse. What condition of the synapse it is remains 
a matter for hypothesis. Close connection might mean pro- 
toplasmic union, or proximity of the neurones in space, or a 
greater permeability of a membrane, or a lowered electrical 
resistance, or a favorable chemical condition of some other 
sort. Let us call this undefined condition which parallels 
the strength of a connection between situation and response 
the intimacy of the synapse. Then the modifiability or 
connection changing ‘of a neurone equals its power to alter 
the intimacy of its synapses. 
As a provisional hypothesis to account for what satisfies 
and what annoys an animal, I ‘Suggest the following : — 
keep intimate those by whose intimacy its other life pro- 
cesses are favored and to weaken the intimacy of those 
whereby its other life processes are hindered..) The animal’s 
action-system as a whole consequently does nothing to avoid 
that response whereby the life processes of the neurones 
other than connection-changing are maintained, but does 
cease those responses whereby such life processes of the 
neurones are hindered. 
This hypothesis has two important consequences. First : 
Learning by the law of effect is then more fully adaptive for 
the neurones in the changing intimacy of whose synapses 
learning consists, than for the animal as a whole. It is 
adaptive for the animal as a whole only in so far as his or- 
ganization makes the neurones concerned in the learning 
welcome states of affairs that are favorable to his life and 
that of his species and reject those that are harmful. 
Second: A mechanism in the neurones gives results in 
