The Arbitrary

In Leonard Peikoff’s presentation of Objectivism, “the arbitrary” names a claim asserted with no supporting evidence at all. Peikoff treats it as a category apart: not merely false but cognitively void, on a separate plane of badness from ordinary mistaken ideas. An arbitrary assertion need not be argued against or refuted; it is to be dismissed outright, because engaging it as if it had cognitive standing concedes too much. The arbitrary is the lowest rung of a four-status scheme — arbitrary, possible, probable, certain — through which Peikoff says an idea climbs the validation ladder as evidence accumulates in its favor.

Critical Fallibilism rejects this entire ladder. CF’s core thesis is that ideas should not be scored by how good they are, on any scale, numeric or not. Peikoff’s grades are exactly such a scale of goodness, so CF discards arbitrary/possible/probable/certain along with credences, support, and probability of being true. CF replaces accumulating evidence with error correction: an idea is either refuted (has a known decisive criticism) or not. There is no separate plane for “no evidence” claims — an unsupported assertion is simply one with no goal it is known to achieve, evaluated like any other against goals and known criticisms.

CF does, however, share Peikoff’s instinct that some claims need not be dignified with rebuttal: an idea backed by no argument carries no problem for you to address, so objectivity permits setting it aside. The disagreement is structural — CF locates this in pass/fail binary judgment, not in a graded hierarchy of cognitive status.