Infallibilism is, in epistemology, the position that knowledge is, by definition, a true belief which cannot be rationally doubted. Other beliefs may be rationally justified, but they do not rise to the level of knowledge unless absolutely certain. Infallibilism's opposite, fallibilism, is the position that a justified true belief may be considered knowledge, even if we can rationally doubt it. Fallibilism is endorsed by virtually all contemporary epistemologists. Fallibilism is not to be confused with skepticism, which is the belief that knowledge is unattainable for rational human beings. René Descartes, an early proponent of infallibilism argued, “my reason convinces me that I ought not the less carefully to withhold belief from what is not entirely certain and indubitable, than from what is manifestly false” Infallibilism can be expressed in logic as 'if I know that p, then I can’t be mistaken about p’ A case against Infallibilism can be made by Howard-Snyder, et.al.’s (2003) zebra case:
We visit the zoo one Saturday morning and rush to our favorite display: the zebra. In the display labeled ‘Equus burchelli’ we see what looks like a zebra. Naturally enough, we believe that there’s a zebra. However, suppose that last night the zookeeper, Fred, inadvertently poisoned the zoo’s only zebra, Zak, and in order to keep zoo-goers from being disappointed, painted his mule, Moses, to look exactly like Zak.
In religion, infallibilism is the belief that certain texts or persons are incapable of being in the wrong. The most famous example of this is probably the Catholic doctrine of Papal Infallibility, under which the Pope is considered infallible in certain matters of doctrine, when his decisions are promulgated ex cathedra (as opposed to personal statements or views). Since 1870, the Church has officially declared that its earthly head, the Pope, in certain circumstances, is so grounded in the mission of the church that he teaches "infallibly." Papal Infallibility also belongs to the body of bishops as a whole, when, in doctrinal unity with the pope, they solemnly teach a doctrine as true.