Full Idea
Composition entails constitution, but does the converse hold? A hand constitutes a fist in virtue of being clenched, but it is not obvious that it composes a fist, and certainly a fist is not composed of a hand plus some additional part.
Gist of Idea
A hand constitutes a fist (when clenched), but a fist is not composed of an augmented hand
Source
Peter Simons (Parts [1987], 6.5)
Book Reference
Simons,Peter: 'Parts: a Study in Ontology' [OUP 1987], p.238
A Reaction
There are subtleties of ordinary usage in 'compose' and 'constitute' which are worth teasing apart, but that isn't the last word on such relationships. 'Compose' seems to point towards matter, while 'constitute' seems to point towards form.