Apropos recent discussions of how theurgy is (just) cultus, a passage from Proclus’ treatise On Providence. Proclus is responding to an argument against providence, where his interlocutor claims that the possibility of knowing the future through divination entails that nothing is up to us.
In §37, Proclus presents the objection, and begins his response by discussing how the foreknowledge humans obtain through divination can prepare us to cooperate (or not cooperate) with coming future events.
In §38, we get the reference to theurgy. Proclus writes:
Besides, not only rites of divination, but also prayers and all the rituals of the priests contribute to these events, people say. Or should we send away and banish the priests, having “anointed them with myrrh and crowned them”? And shall we not allow people to raise their hands, nor allow supplications addressed to those who can repulse the celestial influences? In vain, then, all human beings “always invoke a God” in difficult circumstances in which they have hope, and Apollo himself announced in vain in his oracle that it is possible for those who do these things to escape the punishment that depends on the heavenly cycles, whereas those who fail to do so will inevitably meet with terrible [vengeance]. Yet if it did not depend on them to do something or not do something, how would it not be utterly absurd to make such distinctions and to ascribe what follows from the oracles to their choices? But we should not inveigh against God nor should we do away with the utility of divination and theurgy from human lives… (trans. Steel; his brackets, my emphasis)
Here, Proclus both continues the discussion of divination (since that’s the core of the objection to which he’s responding), and adds in the reference to theurgy. Since all the material that precedes this quote is exclusively about divination, his discussion of “theurgy” must be found in what’s quoted here.
So from this passage, what is indicated by “theurgy”? It’s “prayers and all the rituals of the priests.” It’s people raising their hands, supplicating and invoking the Gods. Here as throughout this treatise, Proclus appeals to the common notions shared by human beings, and to the ordinary practices carried out, in ordinary circumstances, by ordinary people.