Conditions for description are general rules to which language must conform if it is to serve descriptive purposes. It is argued that the existence of such rules renders scepticism about them incoherent. The only way we can decide whether or not there are such conditions is by seeing in practice whether or not there are certain rules such that we cannot in fact break them without making language unfit for describing. The case is similar to that of, e.g., the law (...) of contradiction, which is itself a condition for description. If we find other conditions, the sceptic, like anyone else, will have to accept that he is bound by them no less than he is bound by the law of contradiction. (shrink)

It is generally agreed that the argument about Achilles and the tortoise was intended to prove that the concept of movement was contradictory or ambiguous and therefore that it did not belong in the foundations of ontology. It is suggested here that the argument stands unless we are prepared to define a standard time by means of dynamical concepts. It would be a premature assumption, however, to suppose that Zeno himself should have been so prepared.