Fonseca, Peter (1528–1599)
Peter Fonseca, the neo-Scholastic Aristotelian philosopher, was born at Proença-a-Nova, Portugal, and died at Lisbon. He entered the Society of Jesus at the age of twenty, completed philosophical and theological studies in that order, and spent most of his life as a professor of philosophy at Coimbra, where he was the leader of a group of scholars who produced a famous series of textbooks (Cursus Conimbricensis ). Fonseca has been called the Aristotle of Portugal. His Institutionum Dialecticarum (Eight Books on Logic; Lisbon, 1564), was widely used as a textbook throughout Europe, and in 1625 it was in its thirty-fourth printing.
Basically an interpreter of the philosophy of Aristotle, Fonseca corrected the Aristotelian text then in use, using Greek manuscripts, and started the process of improving the Renaissance Latin versions. His logic is the traditional syllogistic which continued to be taught in Europe until J. S. Mill and the nineteenth-century mathematicians broadened the scope of the subject. As a student Fonseca had, of course, been taught a modified form of Thomism, but he showed a great deal of independence on specific questions. In theory of knowledge he maintained that a singular thing is directly known by the human intellect (contrary to Thomas Aquinas), and he seems to have felt (with the later Ockhamists) that the theory of intelligible species as intellectual determinants of the process of conceptualization is useless.
Fonseca placed great emphasis on the unity of the formal concept of being (influencing Francisco Suárez) and taught that this concept is univocal and not analogical in its reference to individual realities. However, he approximated the Thomistic real distinction of essence and existence by treating essence as an ultimate intrinsic mode of the nature of a thing and existence as a contingent addition to this nature. He is, then, partly responsible for the introduction of the terminology of modes into early modern metaphysics. Fonseca abandoned Thomism in denying that matter is pure potency and in rejecting quantified matter as the principle of individuation in bodies. He explained individuation as due to a positive difference (differentia ) added to the essence of a thing, a theory reminiscent of John Duns Scotus.
works by fonseca
Commentariorum in Libros Metaphysicorum Tomi IV (Commentary on Aristotle's Metaphysics). Vols. I and II, Rome, 1577–1589; Vol. III, Evora, 1604; Vol. IV, Lyons, 1612.
Isagoge Philosophica (Introduction to philosophy). Lisbon, 1591.
works on fonseca
Ashworth, Earline J. "Petrus Fonseca and Material Implication." Notre Dame Journal of Formal Logic 9 (1968): 227–228.
Ashworth, Earline J. "Petrus Fonseca on Objective Concepts and the Analogy of Being." In Logic and the Workings of the Mind, edited by Patricia A. Easton. Atascadero, CA: Ridgeview, 1997.
Coombs, Jeffrey. "The Ontological Source of Logical Possibility in Catholic Second Scholasticism." In The Medieval Heritage in Early Modern Metaphysics and Modal Theory, 1400–1700, edited by Russell L. Friedman. Dordrecht: Kluwer Academic, 2003.
Giacon, C. La seconda scolastica. Vol. II, 31–66. Milan: Fratelli Bocca, 1946.
Gomes, Joaquim F. "Pedro Da-Fonseca, Sixteenth Century Portuguese Philosopher." International Philosophical Quarterly 6 (1966): 632–644.
Nedelhofen, M. Die Logik des Petrus Fonseca. Bonn, 1916.
Vernon J. Bourke (1967)
Bibliography updated by Tamra Frei (2005)