Em meio à exposição acerca dos erros provenientes de certas posições acerca da natureza dos juízos, Brentano faz uma interessante síntese da querela medieval sobre a relação entre essentia e existentia. E ainda que não faça muito mais do que apontar aí aquilo que pensa serem acertos e enganos nas duas teses, é possível entrever algo de sua própria posição:
Meanwhile, this false root naturally put forth various erroneous offshoots which branched out further and extended not only into the domain of psychology, but into those of metaphysics and logic as well. The ontological argument for the existence of God is but one of their fruits.
The fierce disputes in which the Medieval schools engaged concerning essentia and esse, indeed, concerning the esse essentiae and the esse existentiae, are testimony to the convulsive efforts by which an energetic intellectual power strove to master this indigestible element. Thomas, Scotus, Ockham, Suarez—all ardently took part in this fight; each one was correct in his polemics, but none in his positive assertions. The question always turns on whether the existence of a being is the same or a different reality than the being itself. Scotus, Ockham, Suarez rightly deny that it is a different reality (which is very much to Scotus’s credit, especially; in fact in his case it should be regarded as nothing less than a miracle). But as a consequence they fall into the error of thinking that the existence of a thing belongs to the essence of the thing itself, and they regard it as the thing’s most general concept. Here the Thomists’ opposition was correct, although their criticism did not touch upon the real weak point, but was based primarily on the foundation of erroneous assumptions which were held in common. How, they cried, could the existence of a thing be its most general concept?—This is impossible!—Then its existence would follow from its definition, and consequently the existence of a creature would be just as self-evident and antecedently necessary as the existence of the Creator Himself. The only thing which follows from the definition of a created being is that it is not contradictory and hence is possible. The essence of a creature, therefore, is its mere possibility, and every actual creature is composed of two parts, a real possibility and a real actuality. The one is asserted of the other in the existential proposition, and they are related to one another somewhat as Aristotle’s matter and form are related in physical objects. The boundaries of possibility are naturally also those of the reality encompassed in it. Thus existence, which in itself is something limitless and all embracing, is limited in the creature. It is different in the case of God. He is that which exists necessarily in itself, upon which everything accidental depends. He is thus not composed of possibility and actuality. His essence is His existence; the claim that He does not exist is a contradiction. And for this very reason He is infinite. Encompassed by no possibility, His existence is unlimited; He is, therefore, the epitome of all reality and perfection.
BRENTANO, F. Psychology from an Empirical Standpoint, p. 178