by the subject. Sometimes the linkage
keeps the thoughts within the sphere of the same original experience,
and sometimes switches them from one past experience to another, or
even away from any specific past experience to general considerations;
yet always the linkage has this character, that the item that now acts
as stimulus has been formerly combined in observation with the other
item that now follows as the response. One fact recalls another when
the two have been previously observed as belonging together.

But suppose, as is commonly the case, that the fact now present in my
mind has been linked, in different past {378} experiences, with
several different facts. Then two questions demand our attention:
whether all these facts are recalled; and, if not, what gives the
advantage to the fact actually recalled over the others that are not
recalled.

The answer to the first question is plain. The fact first present in
mind does not call up all the associated facts, but usually only one
of them, or at least only one at a time. My neighbor, in the example
given, though previously associated with a dozen other facts, now
calls up but two of these facts, and those two not simultaneously but
one after the other. We see a law here that is very similar to a law
stated under the head of attention. There, we said that of all the
objects before us that might be noticed only one was noticed at a
time; and here we say that of all the objects that might be recalled
to mind by association only one is recalled at a time. Both statements
can be combined into the one general "law of reaction" which was
mentioned before, that of all the responses linked to a given stimulus
(or complex of stimuli) only one is actually aroused at the same
instant, though several may be aroused in succession, provided the
stimulus continues.

In revery, the stimulus usually does not continue. The first fact
thought of gives way to the fact that it recalls, and that to one that
it recalls in turn, and so on, without much dwelling on any fact. But
if we do dwell on any fact--as upon the thought of a certain
person--then this stimulus, continuing to act, calls up in succession
quite a number of associated facts.

If, then, only one of the several facts associated with the stimulus
is recalled at once, our second question presents itself, as to what
are the factors of advantage that cause one rather than another of the
possible responses to occur. The fac