(physics) A physical paradox that arises when considering the buoyant force exerted on a relativistic bullet (or in a submarine) immersed in a fluid subject to an ambient gravitational field. If a bullet has neutral buoyancy at rest in a perfect fluid and is then launched at relativistic speed, observers at rest within the fluid would conclude that the bullet should sink, since its density will increase due to the length contraction effect. On the other hand, in the bullet's proper frame it is the moving fluid that becomes denser and hence the bullet would float.

The situation where a group of people collectively decide on a course of action that goes against the preferences of many or all of the individuals in the group, because the individuals choose to side with what they believe is the majority preference.

(psychotherapy) A psychotherapeutic technique used to treat anxiety by repeatedly rehearsing the anxiety-inducing pattern of thought or behaviour, often with exaggeration and humor.

(physics) A relativistic paradox concerning the concept of Born rigidity within special relativity, where an ideally rigid cylinder that is made to rotate about its axis of symmetry. The radius R as seen in the laboratory frame is always perpendicular to its motion and should therefore be equal to its value R₀ when stationary. However, the circumference should appear Lorentz-contracted to a smaller value than at rest. This leads to the contradiction that R = R₀ and R < R₀.

(medicine) An aggressive behaviour sometimes manifested by patients taking certain drugs, such as benzodiazepines.

plural of paradoxical rage reaction

(set theory) The paradox that supposing the existence of a set of all ordinal numbers leads to a contradiction; construed as meaning that it is not a properly defined set.

The paradox whereby aid agencies report the success of most of their programs, yet it is impossible to establish any significant correlation between aid and GDP growth in developing countries.

A semantic paradox of self-reference, where, supposing that "autological" means "self-describing" and "heterological" means "not self-describing", then "heterological" itself cannot be meaningfully classified as either of the two.

The apparent contradiction that, although water is generally more useful than diamonds, diamonds command a higher price in the market.