EFFORT, THINKING, AND MOTIVATION
strain, but in connection with carrying forward an activity to its fulfillment: it all depends, as we say, upon the end.
Two considerations follow. (1) On the one hand, when an activity persists in spite of its temporary blocking by an obstacle, there is a situation of mental stress: a peculiar emotional condition of combined desire and aversion. The end continues to make an appeal, and to hold one to the activity in spite of its interruption by difficulties. This continued forward appeal gives desire. The obstacle, on the other hand, in the degree in which it arrests or thwarts progress ahead, inhibits action, and tends to divert it into some other channel—to avert action, in other words, from the original end. This gives aversion. Effort, as a mental experience, is precisely this peculiar combination of conflicting tendencies—tendencies away from and tendencies towards: dislike and longing.
(2) The other consideration is even more important, for it decides what happens. The emotion of effort, or of stress, is a warning to think,
