Medieval Logic And Metaphysics

Originally published in 1972, Medieval Logic and Metaphysics shows how formal logic can be used in the clarification of philosophical problems. An elementary exposition of Leśniewski’s Onotology, an important system of contemporary logic, is followed by studies of central philosophical themes such as Negation and Non-being, Essence and Existence, Meaning and Reference, Part and Whole. Philosophers and theologians discussed include St Anselm, St Thomas Aquinas, Abelard, Ockham, Scotus, Hume and Russell.

For medieval thinkers, the distinction between intentional and extra-mental reality does not precipitate a Kantian turn to the subject. Rather, they allow that metaphysics and natural philosophy study things as they are and leave to logic the investigation of things as conceived. Within this broad scheme, there is much room for debate regarding whether and to what extent Aristotle’s categories comprise an accurate picture of what types of things exist. Closely tied to consideration of what types of things exist are questions concerning how language reflects the relations that hold among these things. For instance, both substances and the accidents parasitic on their existence are said to be, but not in the same way. The essays in Categories, and What is Beyond draw on the philosophical traditions of late antiquity and the middle ages to study what types of things there are, the extent to which our knowledge of these entities is accurate, how (and whether) the semantics of analogy are competent to adjust for the difference and diversity found amongst analogates, and some ways in which these considerations bear on our ability to learn and speak of God.

This book begins with standard ontological topics--such as the nature of existence--and of metaphysics generally, such as the status of universals, form, and accidents. What is the proper subject matter of metaphysical speculation? Are essence and existence really distinct in bodies? Does the body lose its unifying form at death? Can an accident of a substance exist in separation from that substance? Are universals real, and, if so, are they anything more than general concepts? Among the figures it examines are Thomas Aquinas, John Duns Scotus, William of Ockham, Walter Chatton, John Buridan, Dietrich of Freiburg, Robert Holcot, Walter Burley, and the 11th-century Islamic philosopher Ibn-Sina (Avicenna).There is also an emphasis on metaphysics broadly conceived. Thus, additional discussions of connected topics in medieval logic, epistemology, and language provide a fuller account of the range of ideas included in the later medieval worldview.

Mereology is the metaphysical theory of parts and wholes, including their conditions of identity and persistence through change. Hylomorphism is the metaphysical doctrine according to which all natural substances, including living organisms, consist of matter and form as their essential parts, where the substantial form of living organisms is identified as their soul. The theories date to Plato and Aristotle and figure prominently in the history of philosophy up until the seventeenth century, where their influence wanes relative to a reductive materialism that culminates with deflationary accounts of objects and persons, where mere conglomerates constitute things and we are left to account for mental phenomena in terms of the powers of physical materials. In view of such difficulties, there is a renewed interest in hylomorphism, as its forms structure matter and can account for natural kinds, with their various capacities and powers. This volume presents medieval theories of hylomorphism and mereology, articulating the conceptual framework in which they developed and with an eye on their relevance today.

One of the most debated topics in medieval philosophy was the metaphysics of identity—that is, what accounts for the distinctness (non-identity) of different individuals of the same, specific kind and the persistence (self-identity) of the same individuals over time and in different possible situations, especially with regard to individuals of our specific kind, namely, human persons. The first three papers of this volume investigate the comparative development of positions. One problem, considered by William of Auvergne and Albert the Great, deals with Aristotle’s doctrine of the active intellect and its relation to Christian philosophical conceptions of personhood. A larger set of issues on the nature and post-mortem fate of human beings is highlighted as common inquiry among Muslim philosophers and Thomas Aquinas, as well as Aquinas and the modern thinker John Locke. Finally, the last two papers offer a debate over Aquinas’s exact views regarding whether substances persist identically across metaphysical “gaps” (periods of non-existence), either by nature or divine power.