"There are at least three major difficulties with nearly all existing models of action in
AI." #readingToday

_There are at least three major difficulties with nearly all existing models of action in
AI. Such models cannot represent:_

– actions that involve non-activity (e.g., ''I stood on the corner for an hour'');
_– actions that are not easily decomposable into subactions (e.g., ''I spent the day
hiding from George'');_
– actions that occur simultaneously and interact with many others.
The theory outlined below will allow all three of these situations to be represented.

Towards a General Theory of Action and Time, J. F. Allen