In the 5th century B.C., Zeno of Elea offered arguments that led to conclusions contradicting what we all know from our experience. The arguments were paradoxes for the ancient philosophers and it took centuries to demonstrate that they were not true. For example, in his Achilles and the tortoise paradox, fast running Achilles races to catch a slower tortoise that has a head start; so, if Achilles hopes to overtake the tortoise, he must run first to the place where the tortoise presently is, but by the time he arrives there, it would have crawled to a new place, so then Achilles must run to this new place, but the tortoise meanwhile will have crawled on, and so forth Achilles will never catch the tortoise, concludes Zeno. From this well known paradox, it appears clearly that from wrong premises come wrong conclusions, something that for years has affected our perception of the role of immunotherapy in kidney cancer.