The Philosophy of Nature of St. Thomas Aquinas / Malebranche Dialogues on Metaphysics and on Religion / The Diffident Naturalist: Robert Boyle and the Philosophy of Experiment

Leo Elders, The Philosophy of Nature of St. Thomas Aquinas (Frankfurt am Main: Peter Lang, 1997), pp. 387. index. ISBN 3-631-31602-X.

Nicholas Jolley and David Scoff (eds.), Malebranche Dialogues on Metaphysics and on Religion, Cambridge Texts in the History of Philosophy, (Cambridge, England: Cambridge University Press, 1997), pp. 287. index.

Rose-Mary Sargent, The Diffident Naturalist: Robert Boyle and the Philosophy of Experiment (Chicago: The University of Chicago Press, 1995), pp. 355. index, bibliography. ISBN 0-226-73497-8.

The Middle Ages inherited an understanding of causation deriving from Aristotelian and Neo-Platonic sources. The three books under review help fill in the picture of the medieval and modern understanding of causation; the third book discusses the emergence of modern experimental philosophy inspired in part by Bacon. I have chosen a few topics within the field of natural philosophy in order to contrast their treatments of causal topics. The first topic is locomotion, the second is qualitative change and perception, and the third is God's causal power.

1. Local Motion 1.1. Thomas Aquinas

Leo Elder's book places Aquinas's views on nature in the context both of medieval thought and of modern speculation. It divides its subject into a general philosophy of nature and a particular philosophy of nature. The second part is in turn divided into three: movement, alteration, and the philosophy of organic life. The third section takes up plant, animal, and human life with chapters on sense perception, cognition, intellect, and will.

Let us begin with something we all take for granted: we often see something moving. This fact is not disputed among the philosophers under review here. But a framework for understanding motion is not shared. Does motion arise from within the ball moving? Is its motion due to its natural heaviness? Or is there an impetus from outside?

Aquinas accepts the Aristotelian view that bodies tend to rest in their natural places. (Elders 111). This view requires an explanation of motion and posits a first mover. The need for a first mover, of course, is at the basis of proofs for the existence of God. The source of motion is either internal (as it can be in substances that have a soul) or external.

The 17th century abandoned the notion of bodies seeking their natural places...