Achilles, the Tortoise and Quantum Mechanics Alfred Driessen prof. emer. University of Twente In several places of his Physica Aristotle analyzes the famous antimony of Zeno about the competition between Achilles and the Tortoise. He emphasizes that any movement, or more general any change, is actually a continuum, i.e. an unity. It depends on the specific movement or change whether this continuum is potentially divisible in parts. In fact, there could be certain minima of the division. In line with this approach, Quantum Mechanics states that there are minima or quanta of movement (or change), with other words, there are no gradual changes in the world of micro- and nano-structures. This behavior is completely unexpected when starting with the mechanistic approach of classical physics. Taking another finding of Aristotle, the four aspects of causality including final cause, one gets another ingredient of Quantum Mechanics. Movements and changes are not only influenced by the initial state -describing the present situation- but also by the final state which takes account of the future situation. As an example one may mention Fermi’s golden rule, where the initial and final state symmetrically determine the transition probability. Bringing these two philosophical concepts of Aristotle together namely quanta of movement and final cause, a new light is shed on fundamental issues in Quantum Mechanics. One may mention the experimental evidence for contextuality, which is considered one of the weird phenomena in Quantum Mechanics. As illustration, some of the examples of experiments with optical microresonators are given. This talk has been presented at the 20th International Interdisciplinary Seminar "Can Science and Technology Shape a New Humanity", Netherhall House, London, 5-1-2018