I normally reply: 'Spontaneously.' However, I hardly ever point out that basically pure spontaneity is in Daoist philosophy recognized as ziran, which is pretty much 'self so' or 'so of itself' or 'so on its own'. However, I would say it is better not to really feel the will need to act, to continue being in wuwei right until ziran decides it. It is the constructive theory straight contrasting the detrimental wuwei.