A mathematical formalism for describing knowledge of the world in terms of patterns that can be studied using statistical methods.

(ecology) A theory regarding the selection of combinations of traits in an organism that represent a trade-off between quantity and quality of offspring.

A speculative theory that human language originated from the imitation of animal vocalisations.

A speculative theory that human language originated from emotional exclamations of pain, pleasure, surprise, etc.

A speculative theory that human language emerged from instinctive noises made by humans during physical exertion, and especially while involved in collective rhythmic labour.

A speculative theory that human language originated from using tongue movements to mimic manual gestures.

(politics) A theorem stating that no voting system can be perfectly fair in all circumstances

(logic) A theorem stating that, in any formal system F with Peano arithmetic, for any formula P, if it is provable in F that "if P is provable in F then P is true", then P is provable in F.

(mathematics) A theorem stating that any non-singular algebraic curve defined by algebraic number coefficients represents a compact Riemann surface which is a ramified covering of the Riemann sphere, ramified at three points only.

(economics) A theorem stating that, if trade in an externality is possible and there are sufficiently low transaction costs, bargaining will lead to a Pareto efficient outcome regardless of the initial allocation of property.