During a delightful rural ramble outside Prague, I mentioned to Daniel Novotný that Arthur Schopenhauer had a high opinion of Francisco Suárez (1548-1617). Daniel said he had heard as much but wondered where Schopenhauer had indicated his high regard for the scholastic philosopher. Here are some passages, though I have the sense that I am overlooking a more striking quotation than any of the ones I have just now managed to locate.
1. There is a place in the early On the Four-Fold Root of the Principle of Sufficient Reason where Schopenhauer is speaking of the four causes mentioned by Aristotle at Analyt. Post., II, 11. Schopenhauer describes the Metaphysical Disputations of Suárez as diesem wahren Kompendio der Scholastik, "this true compendium of scholasticism." (Ueber die vierfache Wurzel des Satzes vom zureichenden Grunde, Zweites Kapitel, sec. 6, Felix Meiner Verlag, Hamburg, p. 15.)
If the index to Schopenhauer's magnum opus, The World as Will and Representation (two vols., tr. Payne, Dover) is to be trusted, there are exactly six references to Suárez all of them in the first volume.
2."It was known even to the scholastics [note 24: Suarez, Disputationes metaphysicae, disp. III, sect. 3, tit. 3.] that, because the syllogism requires two premisses, no science can start from a single main principle that cannot be deduced further; on the contrary, it must have several, at least two, of these." (p. 63)
3. "Consequently, time and space are the principium individuationis, the subject of so many subtleties and disputes among the scholastics which are found collected in Suárez (Disp. 5, sect. 3)." (p. 113)
4. "That which for man is his unfathomable character, presupposed in every explanation of his actions from motives, is for every inorganic body precisely its essential quality, its manner of acting, whose manifestations are brought about by impressions from outside, while it itself, on the other hand, is determined by nothing outside it, and is thus inexplicable. Its particular manifestations, by which alone it becomes visible, are subject to the principle of sufficient reason; it itself is groundless. In essence this was correctly understood by the scholastics, who described it as forma substantialis. (Cf. Suárez, Disputationes Metaphysicae, disp. XV, sect. 1.) (p. 124)
5. P. 152, fn. 21: "The scholastics therefore said quite rightly: Causa finalis movet non secundum suum esse reale, sed secundum esse cognitum. See Suárez, Disp. Metaph., disp. XXIII, sect. 7 et 8. ('The final cause operates not according to its real being, but only according to its being as that is known.' [Tr.]"
6. The following excerpt is from "Criticism of the Kantian Philosophy," an appendix to the first volume of WWR, pp. 422-423, emphasis added):
We may regard as the third point the complete overthrow of the Scholastic philosophy, a name by which I wish here to denote generally the whole period beginning with Augustine, the Church Father, and ending just before Kant. For the chief characteristic of Scholasticism is, indeed, that which is very correctly stated by Tennemann, the guardianship of the prevailing national religion over philosophy, which had really nothing left for it to do but to prove and embellish the cardinal dogmas prescribed [pg 013] to it by religion. The Schoolmen proper, down to Suárez, confess this openly; the succeeding philosophers do it more unconsciously, or at least unavowedly. It is held that Scholastic philosophy only extends to about a hundred years before Descartes, and that then with him there begins an entirely new epoch of free investigation independent of all positive theological doctrine. Such investigation, however, is in fact not to be attributed to Descartes and his successors, but only an appearance of it, and in any case an effort after it. Descartes was a man of supreme ability, and if we take account of the age he lived in, he accomplished a great deal. But if we set aside this consideration and measure him with reference to the freeing of thought from all fetters and the commencement of a new period of untrammelled original investigation with which he is credited, we are obliged to find that with his scepticism still lacking in true earnestness, and thus abating and passing away so quickly and so completely, he has the appearance of wishing to discard all at once all the fetters of the early implanted opinions belonging to his age and nation; but does so only apparently and for a moment, in order to assume them again and hold them all the more firmly; and it is just the same with all his successors down to Kant.
7. "The word 'Idea,' first introduced by Plato, has retained ever since, through twenty-two centuries, the meaning in which he used it; for not only all the philosophers of antiquity, but also all of the scholastics, and even the Church Fathers, and the theologians of the Middle Ages, used it only with that Platonic meaning, in the sense of the Latin word exemplar, as Suárez expressly mentions in his twenty-fifth Disputation, Sect. 1." (p. 488)