infallible

Infallible is an adjective describing something that is incapable of making mistakes or being wrong. In everyday language it may describe a person, belief, or system that is exceptionally reliable; in practice, speakers often use it hyperbolically to express strong confidence. In philosophy and epistemology, infallibility is considered in relation to the possibility of error: even strong theories may be fallible, and most knowledge is treated as provisional rather than certain.

Etymology: the word comes from Latin infallibilis, formed with in- “not” + fallibilis “liable to err,” from fallere “to deceive or err.” The term has given rise to related expressions in many languages, used to signify absolute reliability or certainty in various domains.

Religious doctrine: in Roman Catholicism, papal infallibility is a defined doctrine stating that the pope, when speaking ex cathedra on matters of faith or morals, is preserved from error. This does not claim personal impeccability or sinlessness, nor does it apply to every utterance by the pope. In other traditions, discussions of infallibility or scriptural inerrancy are approached differently and are often subject to debate and nuance.

Secular usage and criticism: in non-religious contexts, infallibility is typically treated as an ideal, not a practical reality, with most individuals and institutions acknowledged to be fallible. In science and philosophy, the aim is robust, testable explanations rather than absolute certainty, and theories remain open to revision in light of new evidence.