Definition of Action
Definition Last Updated 17-Dec-2015 12:51
An action is a unit of activity for which no internal description is provided, i.e. it is an event (potentially of extended duration), characterised entirely by a specified change in state. Defined thus, in terms of changes of state, an action may be seen as the occurrence of an exercise of a ; actions may be performed by a performer – but they might also simply be reactions, i.e. an effect arising from a particular cause.
It may be possible, and indeed it usually is, to divide an action into smaller actions; whilst this may appear to convert an action into an activity (given that the description of a thing should be fixed unless it is acted upon), activity is the fundamental concept: an activity may be described as an action only for the actor who is unable to interrupt it.