Full Idea
In sentential logic there is a simple proof that all truth functions, of any number of arguments, are definable from (say) 'not' and 'and'.
Gist of Idea
In sentential logic there is a simple proof that all truth functions can be reduced to 'not' and 'and'
Source
Leslie H. Tharp (Which Logic is the Right Logic? [1975], §0)
Book Reference
'Philosophy of Logic: an anthology', ed/tr. Jacquette,Dale [Blackwell 2002], p.35
A Reaction
The point of 'say' is that it can be got down to two connectives, and these are just the usual preferred pair.