Voluntarism is the classical compatibilist definition of freedom as freedom from coercions. Today this negative freedom includes freedom from internal constraints as well, such as addictions or mental disabilities. Mortimer Adler and Robert Kane call this self-realization, contrasting the negative freedom of voluntarism with the libertarian positive freedom of self-determination. Honderich calls it voluntariness, contrasting it with the libertarian freedom of origination, without which, he says, we are not the authors of our own actions. The ancient Greeks had the ideas of spontaneity and origination, but it is difficult to identify specific Greek terms with these ideas. For example, the idea that at least some of our actions are "up to us," that we can be the "authors of our own actions," and that they are not caused by external events, is perhaps the most ancient concept of "free will." Although the Romans had the same complex combination of free and will in their term (liberum arbitrium or libera voluntas), the Greeks had no such combination. For the Greeks, and particularly for Aristotle, the term closest to the modern complex idea of free will, (which combines freedom and determination in an apparent internal contradiction) was ἐφ ἡμῖν - "on us" or "depends on us." The original idea was thus supportive of accountability or moral responsibility, that our actions originate "within ourselves" (ἐν ἡμῖν), that as "agents" we are "causes" that are the fresh starting points (ἀρχάι) of new causal chains. Despite calling free will a "pseudo-problem" that could be resolved (or "dis-solved") by careful attention to the proper use of language, no analytic language philosopher appears to have resolved the one complex idea into two opposing but complementary concepts. Analytic philosophers should note that John Locke was in the seventeenth century quite concerned that misuse of language lay behind the problem. In the Essay Concerning Human Understanding, Book II, Chapter XXI, Of Power, we find in section 14 that Locke calls the question of Freedom of the Will "unintelligible" (as had Thomas Hobbes before him). But for Locke, it is only because the adjective "free" applies to the agent, not to the will, which is determined by the mind, and which determines the action. This seems to be Aristotle's view as well. Here is how he put it in Nicomachean Ethics, III, v, 6.
εἰ δὲ ταῦτα φαίνεται καὶ μὴ ἔχομεν εἰς ἄλλας ἀρχὰς ἀναγαγεῖν παρὰ τὰς ἐν ἡμῖν, ὧν καὶ αἱ ἀρχαὶ ἐν ἡμῖν, καὶ αὐτὰ ἐφ' ἡμῖν καὶ ἑκούσια. But if it is manifest that a man is the author of his own actions, and if we are unable to trace our conduct back to any other origins than those within ourselves, then actions of which the origins are within us, themselves depend upon us, and are voluntary. (Loeb translation.)