Speaking in the abstract, the will may assume one of three distinct attitudes toward sufficient grace. It may consent, it may resist, or it may remain neutral. It cannot consent except with the aid of a predetermining _gratia efficax_, to merit which is beyond its power. If it withstands, it _eo ipso_ renders itself unworthy of the _gratia efficax_. If it takes a neutral attitude, (which may in itself be a sinful act), and awaits efficacious grace, of what use is sufficient grace?
To resist sufficient grace involves an abuse of liberty. Now, where does the right use of liberty come in? If coöperation with sufficient grace moves God to bestow the _gratia per se efficax_, as the Thomists contend, then the right use of liberty must lie somewhere between the _gratia sufficiens_ and the _gratia efficax per se_. But there is absolutely no place for it in the Thomistic system. The right use of liberty for the purpose of obtaining efficacious grace is attributable either to grace or to unaided nature. To assert that it is the work of unaided nature would lead to Semipelagianism. To hold that it is owing to grace would be moving in a vicious circle, thus: “Because the will offers no resistance, it is efficaciously moved to perform a salutary act; that it offers no sinful resistance is owing to the fact that it is efficaciously moved to perform a salutary act.”(726)
It is impossible to devise any satisfactory solution of this difficulty which will not at the same time upset the very foundation on which the Thomistic system rests, viz.: “_Nulla secunda causa potest operari, nisi sit efficaciter determinata a prima [scil. per applicationem potentiae ad actum]_,” that is to say, no secondary cause can act unless it be efficaciously determined by the First Cause by an application of the latter to the former as of potency to act.
b) The Thomistic _gratia efficax_, conceived as a _praedeterminatio ad unum_, inevitably destroys free-will.
α) It is important to state the question clearly: Not physical premotion as such,(727) but the implied connotation of _praevia determinatio ad unum_, is incompatible with the dogma of free-will. The freedom of the will does not consist in the pure contingency of an act, or in a merely passive indifference, but in active indifference either to will or not to will, to will thus or otherwise. Consequently every physical predetermination, in so far as it is a _determinatio ad unum_, must necessarily be destructive of free-will. Self-determination and physical predetermination by an extraneous will are mutually exclusive. Now the Thomists hold that the _gratia per se efficax_ operates in the manner of a supernatural _praedeterminatio ad unum_. If this were true, the will under the influence of efficacious grace would no longer be free.