320. Philosophical Teaching. -- Giles professes an eclectic Thomism, not sufficiently known. Following St. Thomas, he defends the real distinction between essence and existence, and between substance and faculties, the substantial simplicity of immaterial beings, the unity of form,^{1} the function of materia signata in individuation, the possibility of creation ab aeterno. But his eclecticism is revealed in his attachment to certain clearly Augustinian theses: the rationes seminales in physics, voluntarism in psychology and ethics, and in his manner of conceiving the relations between the Divine Science and the Divine Volition.^{2} To reconcile the Augustinian trilogy of the powers of the soul (memoria, intellectus, voluntas) with Aristotle's ideology, Giles identifies the intellectus agens with the intellectus possibilis. This has the effect of disfiguring his theory of knowledge with doubts and inconsistencies.^{3}

The treatise De Partibus Philosophiae Essentialibus reproduced the current thirteenth-century classification of the philosophical sciences (277): but Giles emphasizes the psychological grounds of this classification: the work thus contains some original views, and according to Baur^{4} it is the last treatise of its kind that possesses this merit.

{1} The treatise De Erroribus Philosophorum, attributed to Giles, opposes the unity or forms, whilst the De Gradibus Formarum defends this theory. One or other is certainly not the work of Giles -- the former in our opinion. DE WULF, Le Traits de Unitate Formae de G. de Lessines, p. 776.

{2} In theology, Giles emphasizes the practical and affective side of the science.

{3} According to WERNER, who attributes this theory to him (Der Augustinismus des späteren Mittelalters, pp. 23, 730), Giles defended elsewhere the real distinction between the two intellects. According to the same author, the image of the Blessed Trinity in man would not affect the essence of his soul, but only the operative powers of the latter; and this would be a point of difference between the doctrine of Giles and that of St. Thomas (p. 20). So too, while admitting that the existence of God is proved a posteriori, Giles would also have held that the proposition "God exists" is per se nota, at least for the learned. Werner's exposition is not easy to follow. His assertions need verification.

{4} BAUR, op. cit., pp. 380, 384. The following is the classification given by Giles: Philosophia: I. Scientia de entibus causantibus nostram scientiam (speculativa): Physica -- Mathematica -- Theologia. II. Scientia de entibus causatis a nobis (practica): de intentionalibus (logica) -- de realibus (moralibus). Baur mentions, as devoid of all originality, a treatise of ARNULPHUS PROVINCIALIS and certain anonymous tracts dealing with the same subject.