Full Idea
Action theorists distinguish between activity verbs such as 'weep' and 'talk' (where continuous entails perfect - John is weeping so John has now wept), and performance verbs like 'wash', where John is washing doesn't yet mean John has washed.
Gist of Idea
With activities if you are doing it you've done it, with performances you must finish to have done it
Source
Peter Simons (Parts [1987], 4.2)
Book Reference
Simons,Peter: 'Parts: a Study in Ontology' [OUP 1987], p.137
A Reaction
How to distinguish them, bar examples? In 'has wept' and 'has washed', I'm thinking that it is the 'has' which is ambiguous, rather than the more contentful word. One is 'has participated' and the other is 'has completed'. I've participated in washing!