Act(ion)-type See ACTION THEORY, TYPE THEORY.

Action at a distance See FIELD THEORY.

Action theory the study of the ontological structure of human action, the...

Action verb a verb applied to an agent and describing an activity,...

Action, basic See PHILOSOPHY OF ACTION.

Action, philosophy of See ACTION THEORY.

Active euthanasia See EUTHANASIA.

Active power See POWER.

Activity verb See ACTION VERB.

Actual infinite See ARISTOTLE.

Actual occasion See WHITEHEAD.

Actual reality See REALITY.

Actualism See GENTILE.

Actualist See MODAL LOGIC.

Actuality See POSSIBLE WORLDS.

Actualization, first See ARISTOTLE.

Actualization, second See ARISTOTLE.

Ad hoc See CURVE-FITTING PROBLEM.

Ad hoc hypothesis See CURVE -FITTING PROBLEM.

Adam de Wodeham See WODEHAM.

Adaptation See DARWINISM.

Adaptive system See COMPUTER THEORY.

Adelard of Bath (c.1070–c.1145), English Benedictine monk notable for his contributions to the...

Adequacy, analytic See MATERIAL ADEQUACY.

Adequacy, material See MATERIAL ADEQUACY.

Adequation See HUSSERL.

Adhyaatman (Sanskrit, 'relating to or belonging to the self'), in early...

Adiaphora See STOICISM.

Adicity See DEGREE.

Adjunction See CONJUNCTION INTRODUCTION.