According to Fabro, the judgmental knowledge of ‘existence’ so emphasized by Gilson is preceded by the intellect’s direct and immediate apprehension of the actus essendi. Fabro was familiar with Gilson’s position and strongly argued against it. In Fabro’s view it is not through the ‘act of judgement’ that the mind has access to the notion of actus essendi.
Fabro addresses the issue in his “The Transcendentality of Ens-Esse and the Grounds of Metaphysics” (International Philosophical Quarterly, 6, pp 389-427, 1966) in unequivocal terms.
[The following clarification] concerns the locus intentionalis of esse or the actus essendi, that is, the phase or function of the mind that grasps reality insofar as it is in act. Such an absolutely primary function, when it is a question of ens, stands poles apart from abstraction and cannot be an object of abstracting reflection properly so-called, but only of direct and immediate apprehension. One interpretation, quite widespread among Neo-Thomists, tries to resolve the question with a good deal of elegance: just as in simple apprehension ‘essence’ is grasped, so too in the judgment esse is grasped. (See Actualite et originalite de l’esse thomiste, Revue Thomiste, 56, 1956, p. 485 and Participazione e Causalita, Italian Ed., p. 41.) They maintain that the texts of Thomas are explicit on this meaning: Cum in re duo sint quidditas rei et esse eius, his duobus respondet duplex operatio intellectus. Una quae dicitur a philosophis formatio, qua apprehendit quidditates rerum. Alia autem comprehendit esse rei componendo affirmationis. (See In I Sent. 37, 1, 3, In I Sent. 19, 5, 1, and In Boeth. De Trin. 5, 3.) But let it be said for the peace of us all: these and other similar texts do not treat at all of our precise question: they deal with the characteristic function of the two operations of the mind which divide the two-fold content of the notion of ens, ‘essence’ and actus essendi. Therefore, the notio entis precedes them both, just as, in fact, ens precedes res and verum in the grounding of the transcendentals.