そう (pro-form)

The word そう used as a pro-form ('pronoun-like') standing in for a previously mentioned action, state, or idea — 'so, like that.' そうした ('did so'), そうなる ('become so'), そう言う ('say so'), 私もそうだ ('I am like that too / me too'). Compresses anaphora compactly. Distinct from the appearance-based ~そう ('looks like, seems').