Entry 0244: Aquinas’ Five Ways and Aristotle (VII)
Concerning Aristotle’s influence on the formulation of the
Way, in his The Philosophical Theology of St. Thomas Aquinas,
([Leiden, The Netherlands: E. J. Brill, 1990], 121-125) Leo Elders writes:
“The teleological argument is that proof of God’s existence which is most widely found in religious and philosophical tradition. The reason is that it is obvious to man that order does not come from nothing but requires someone who arranges things.
“In the prologue to the Lectura super Evang. Ioannis St. Thomas calls this the most efficacious way.
“Aristotle gives a version of this proof of God in De philosophia (Fr. 10 R). And in Metaph. XII 10, 1076 a 3 Aristotle attributes to Homer the thesis that there must be one principle which governs the cosmos.
St. Thomas agrees with Aristotle that this
teleological organization shows most in animal life (In II Phys., I.13, n.259).
“Against the objection that it is impossible to speak of finality in inanimate bodies,
St. Thomas maintains that natural things
without knowledge act for an end, because they always act in the same way so as
to obtain the best result (‘id quod est optimum’).
“What does Aquinas mean by his statement that these natural things are always or almost always acting in the same way and reach what is best? When we read this text against the background of the commentary on Aristotle’s Physics II, lesson 13 which explicitly studies this question, we notice that to act for an end is distinguished from chance events. What happens by chance is not directed towards a certain purpose. The classic example is that of a tile falling from a roof which hits a pedestrian who happens to be passing.
“It is impossible that things which happen always or in most cases in the same way, come about by chance. (The wording of the first lines of the
Way is very close to Aristotle’s text [Phys. II, c.8] and that of St. Thomas commentary [ibid.,
n.256]). The reason is that in chance events there is no intended connection
between an action and the result obtained. Therefore this result comes about in
a capricious manner.
“In the activity of natural things where there is a final term, there is an intended connection between the action itself and its result.
St. Thomas explains this in his already
quoted commentary: when something is done naturally in a certain way, it has a
natural disposition and aptitude (‘aptum natum est’) to be done in this way (In II Phys., n.257). This is precisely
what Aristotle writes himself: ‘and as they are by nature such as to be, so
they are done, if there is no impediment’ (Phys.,
199 a 10 transl. by W. Charlton).
“What Aristotle writes is obvious: every year in spring the sun climbs higher in the ecliptic, it warms the atmosphere and the higher temperature melts the snow; the chemical elements react with one another according to a set affinity; in the course of the seasons of the year plants act always or almost always in a regular pattern to reach certain ends. They do so according to their natural aptitude. Nature has fitted them out in such a way that these activities follow conveniently and easily. (See In II Phys., I,12, n.252.)”