A line of eclectic social science theories and research with its roots in a Soviet theory pioneered by Sergei Rubinstein in the 1930s, seeking to understand human activities as systemic and socially situated phenomena and to go beyond paradigms of reflexology and classical conditioning.

(cognitive science, psychology) A theory of categorization in cognitive science, particularly in psychology and cognitive linguistics.

An informal metaphor for chronic illness or disability that uses "spoons" to represent the finite units of physical and mental energy that a person has available for daily tasks.

(film) The view of film as an art form with an original and personal stylistic vision, especially in contrast to collective authorship in the studio system.

(mathematics, computer science) A branch of mathematical logic and theoretical computer science concerned with types.

The idea that morality is simply a cultural manner that hides man's innate amorality.

(mathematics) The study of harmonic functions.

(physics) A proposed mechanism, involving a rotating, convecting, and electrically conducting fluid, by which a celestial body generates and maintains a magnetic field over astronomical time scales.

(mathematics) The study of iterative non-linear systems in which arbitrarily small variations in initial conditions become magnified over time.

(mathematics) The branch of pure mathematics concerned with the properties of integers.