, may be
intrinsically delightful and self-sufficient activity. Under the
conditions of modern industry, however, especially of machine
production, much--in many cases, most--of the activity
by which an individual earns his living, utilizes only some of
his native tendencies to act, while the working day does not,
under normal conditions, absorb all his energy. Whatever
vitality is not, therefore, absorbed in necessary work goes into
forms of purely gratuitous activity. Which form "play"
shall take in the adult depends on the degree to which certain
impulses are in him stronger than others, either by native
endowment or cultivation, and which impulses have not been
sufficiently utilized in him during the day's work. A man
musically gifted will find his recreation in some performance
on a musical instrument, let us say; on the other hand, if his
work is music, those impulses, strong though they be, that
make him a musician, will have been sufficiently exhausted in
the day's work to make some other activity a more satisfactory
recreation.

The relations between play and work can be better understood
by a consideration of the physiological importance of
variety in activity. A certain regular recurrence of response
may be pleasant, as in rowing or canoeing, or in listening to
the rhythms of poetry or music, but a prolonged repetition of
precisely the same stimulus or the same set of stimuli may
make responses dissatisfying to the degree of pain. Ideal
activity, biologically, would be one where every impulse was
just sufficiently frequently called upon to make response easy,
fluent, and satisfactory.

The reason "work" has traditionally come to be regarded
as unpleasant and "play" as pleasant is not because the former
is activity and the second is torpor. Leisure does not necessarily
mean laziness. Many a vacation, a camping party, a
walking expedition, is literally more strenuous than the work
an individual normally does. But work means human energy
expended for the sole purpose of accomplishing some end.
And an end involves the deliberate shutting-out of every
impulse which does not contribute to its fulfillment. A man
weeding a garden may tire of the weeding long before he is
really physically exhausted. One response is being repeatedly
made, while at the same time a dozen other impulses are
being stimulated. When Tom Sawyer, under the compulsion
of his aunt, is whitewashing a fence, it is shortly no fun for
him.