An apparent paradox within the subjectivistic interpretation of probability theory, in which two people wager over whose necktie is cheapest, with the owner of the more expensive tie giving it to the other. Taking the wager seems to be to the advantage of both people.

(economics) The phenomenon that uncertainty about future prices can theoretically push rational consumers to temporarily trade away their preferred consumption goods (or currency) for non-preferred goods (or currency), as part of a plan to trade back to the preferred consumption goods after prices become clearer.

(computing, robotics) The observation that, contrary to traditional assumptions, reasoning (which is high-level in humans) requires very little computation, but sensorimotor skills (comparatively low-level in humans) require enormous computational resources.

(probability) A problem within the classical interpretation of probability theory, illustrating how the principle of indifference may not produce definite, well-defined results for probabilities if it is applied uncritically when the domain of possibilities is infinite.

plural of twin paradox

The observation that, because of the very large number of degrees of freedom in an unfolded polypeptide chain, the molecule has an astronomically large number of possible conformations, and therefore sequentially sampling all the possible conformations is not practical, yet most small proteins fold spontaneously on a millisecond or even microsecond timescale.

The situation in which a phenomenon being observed for study is unwittingly influenced by the presence of the observer.

(logic) A paradox arising from vague predicates and repeatedly applying a small difference. For example, removing one grain from a heap of sand still leaves a heap, yet removing enough grains will eventually not leave a heap.

plural of sorites paradox

A paradox of choice in which people's decisions produce inconsistencies with subjective expected utility theory.