Anthony Kenny criticized the Five Ways, by Thomas Aquinas, in a widespread and influential book. About the First Way, among other critiques, Kenny considers that Thomas Aquinas failed to prove that “whatever is in motion is put in motion by another”. As this principle is central for the argument developed by Aquinas on the “first mover, put in movement by no other”, the First Way is insufficient and grounded on a mistake. In this article, Aristotle’s and Aquinas’s works are analysed (...) to expose that their arguments about movement are sound and persuasive. On the contrary, Kenny’s criticism is not consistent and is misled by bad interpretation of texts and concepts. Oderberg and Weisheipl agree with Aquinas and Aristotle, and their papers reinforce the conclusions of this article, favourable to the Medieval philosopher and against Kenny. (shrink)