The graph is 心, heart, under 之, to go: the heart going toward something. That is the sense the texts use — not willpower but direction.

Suwen 2 gives the will a different instruction in every season. In spring, cause it to grow (以使志生). In summer, keep it from anger (使志無怒). In autumn, settle it (使志安寧) and do not send it outward (無外其志). In winter, as though crouching, as though concealed (使志若伏若匿). Four seasons, four directions for the same thing.