On the contrary, it is perfectly cogent. Nor does it contradict observed reality.Read Thomas’ First Way again. The First Mover can only be a Being having no potency, a pure act, a spirit, owing its existence to no other. Thomas, after Aristotle, begins with " observed reality," things which are moved and changed. But one cannot go on endlessly in such a series. One must come to some Being which is pure act.
This is the culmination of Thomas’ analysis of Aristotle’s entire philosophy ( with necessary corrections, which is summed up in Thomas’ Commentaries on Aristotle’s Physics and Metaphysics (
dhspriory.org/thomas/ ).
Thomas immediately recognized such a Being met the criteria of the God of Christianity. God said to Moses, " …tell the Israelites
I Am sends you…" This is Thomas’ conclusion to the First Way. Then he proceeds in the remainder of Part 1 of the Summa to analyse and explain the attributes of the Unmoved Mover, which necessarily follow.
This is perfectly legitimate and is no different than the what science does; for example, following out the " implications " involved in General and Special Relativity. Except that science is drawing out the physical " implications, " whereas Thomas is drawing out the metaphysical or ultimate underlying causes/meaning of his discovery.
Edward Feser gives a good analysis of the Five Ways in his Aquinas with further explanations in his blogspot (
edwardfeser.blogspot.com/ ) and he explains many of the underlying principles in his forthcoming book, Scholastic Metaphysics: A Contemporary Introduction…
Of course all of this is simply an intellectual explanation of what St. Paul meant when he said, " The evidence of Him is in the things He has made. "
Feser gives concrete examples of the causes of the movement of things which are moved.
I will give you a concrete example based on Aristotle’s notion of Nature. Aristotle gives a detailed explanation of this Principle in his Physics which is thoroughly analysed in Thomas’ Commentary of this work. Aristotle teaches that, " Nature is the principle of motion and rest in those things to which it belongs
per se." Fr. John A. Weisheiple ( RIP ) in his Motion and Change in the Middle Ages, explains and draws out the implications of this principle in a detailed, exhaustive manner. My example is based on his exposition.
Take a body, natural or man made, hurtling through space. This object is moving under some power, there is a cause of its motion. It does not " move it self, " as Aristotle has proven. This object has a potency to be moved or it would not move, which principle he has proven. Nothing moves itself from potency to act, from non being to being. Something has given this object the power of movement. Something then must have moved it. It is obvious that nothing is accompanying the object in its motion, so the power of motion is in the object, it is something flowing from its very nature. Its nature has been changed so that it retains the power of moving through the external application of some impetus. The cause of this impetus, ultimately, can only be a Being which is Pure Act, which has created the " thing’s " Nature, giving it the potential to be modified by an externally applied impetus. In other words the object is moved, naturally by its modified nature and will continue to move until it encounters some other contrary force.
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