  Both promising and communicating one's intention to do something, according to Reinach, belong to the category of what he calls “spontaneous” acts, i.e. acts which involve a subject's bringing something about within his own psychic sphere, as contrasted with passive experiences of, say, feeling a pain or hearing an explosion (1913, p. 706, Eng. p. 18). Certain types of spontaneous act are such as to require as a matter of necessity a linguistic utterance or some other overt performance of a non-natural and rule-governed sort. This does not hold of judging or deciding, nor even of forgiving, but it does hold of apologizing, commanding, or accusing. We may accordingly divide spontaneous acts into two classes, which we might call internal and external, according to whether the act's being brought to overt expression is a separable or an inseparable moment of the relevant complex whole.