"Scientists have proof/proven that photovoltaic cells convert sunlight into energy."
Are both proof and proven correct in this sentence ?
[AmE - not a teacher]
Notice that one form of the word is a noun, while the other is a verb. Perhaps this crude example will help show the difference:
"I have a piece of paper that shows evidence that ... "
The piece of paper would be having the proof.
Showing evidence would be the proving.
Indeed, one could say:
"Scientists have proof proving that ... " or "Scientists have proven with proof that ... " (though the redundancies sound very awkward.)
Last edited by BobSmith; 01-Mar-2012 at 11:32.