vicious regress regress that is in some way unacceptable, where a regress is an infinite series of items each of which is in some sense dependent on a prior item of a similar sort, e.g. an infinite series of events each of which is caused by the next prior event in the series. Reasons for holding a regress to be vicious might be that it is either impossible or that its existence is inconsistent with things known to be true. The claim that something would lead to a vicious regress is often made as part of a reductio ad absurdum argument strategy. An example of this can be found in Aquinas’s argument for the existence of an uncaused cause on the ground that an infinite regress of causes is vicious. Those responding to the argument have sometimes contended that this regress is not in fact vicious and hence that the argument fails. A more convincing example of a vicious regress is generated by the principle that one’s coming to know the meaning of a word must always be based on a prior understanding of other words. If this principle is correct, then one can know the meaning of a word w1 only on the basis of previously understanding the meanings of other words (w2 and w3). But a further application of the principle yields the result that one can understand these words (w2 and w3) only on the basis of understanding still other words. This leads to an infinite regress. Since no one understands any words at birth, the regress implies that no one ever comes to understand any words. But this is clearly false. Since the existence of this regress is inconsistent with an obvious truth, we may conclude that the regress is vicious and consequently that the principle that generates it is false.
See also EPISTEMIC REGRESS ARGUMENT , REDUCTIO AD ABSURDU. W.T.