Diego Alvarez states the Thomist view and its definition of free choice
Diego Alvarez, archbishop of Trani and Salpi and the leading figure among the more recent Thomists, explains his view as follows.
'It must be held that freedom of choice necessarily requires this: given everything required before the act, whether in order of reason or of time, it can act or not act. That is, together with those same prerequisites there is present in free choice the faculty and power by which it can act or not act, if it wishes.
'The proof is this. If any of the things required for performing a given act took from free choice the faculty or power of not acting, or of performing the opposite act, it would be God's efficacious motion by which free choice is predetermined to that act. But such motion does not remove the faculty of not performing that act or of performing the contrary one. It brings about only this: free choice, though able to perform the act or not, does in fact perform it infallibly and freely...
'Yet it is not part of the nature or definition of free choice that, given all that is required in advance in the order of causality for performing a given act, it can leave that same act undone in the composed sense, if the composition is made between those prerequisites and the absence of that act, or the contrary act.
'So these two things cannot coexist: that in free choice, at some instant of time, all that is required in advance in the order of causality for producing a given act is present, and yet it does not produce that act but produces the contrary. And freedom of choice nevertheless stands together with this impossibility.' (Summary of the work on the aids of divine grace, book 4, chapter 14, nos. 5 and 6.)
To avoid all ambiguity, then, the proper definition of free choice on his account is: 'Free choice is the faculty of will and reason for acting or not acting, either way, and for doing one thing or another.'
Latin
XLIX. Sic mentem suam hac de re exponit Didacus Alvares Archiepiscopus Tranensis & Salpensis, inter recentiores Thomistas praecipuus. Dicendum est, inquit, ad libertatem arbitrii necessario requiri, quod positis omnibus antecedenter secundum ordinem rationis vel temporis ad actum praerequisitis possit operari, vel non operari, ita videlicet, ut cum iisdem praerequisitis stet simul in libero arbitrio facultas & potentia, qua possit operari, vel non operari, si velit. Et probatur, Nam si aliquod ex praerequisitis ad operandum talem actum in particulari tolleret a libero arbitrio facultatem, seu potentiam ad non operandum, vel ad operandum actum oppositum; id efficeret motio Dei efficax, qua ad talem actum praedeterminatur: sed hujusmodi motio non tollit a libero arbitrio facultatem non operandi illum actum, vel operandi actum contrarium, sed solum efficit, quod cum liberum arbitrium possit operari, & non operari talem actum; infallibiliter tamen & libere operetur illum.... Non tamen est de ratione, aut definitione liberi arbitrii, quod positis omnibus, secundum ordinem causalitatis antecedenter praerequisitis, ad operandum talem actum, possit eundem actum non operari in sensu composito, si compositio fiat inter ejusmodi praerequisita, & carentiam talis actus, seu actum contrarium. Itaque haec duo simul sunt incompossibilia, quod scilicet, in libero arbitrio, pro aliquo instanti temporis, sint omnia antecedenter praerequisita secundum ordinem causalitatis, ad productionem talis actus, & non producat illum sed producat actum contrarium. Et nihilominus cum hac impossibilitate stat simul libertas arbitrii. In summa operis de auxiliis Divinae gratiae lib. 4. cap. 14. num. 5. & 6. Ideoque ad vitandam omnem aequivocationem, haec est, juxta ipsum, liberi arbitrii legitima definitio, liberum arbitrium est facultas voluntatis, & rationis ad utrumlibet agendum, vel non agendum, & agendum unum, vel alterum.