constructing or tending to construct or improve or promote development; "constructive criticism"; "a constructive attitude"; "a constructive philosophy"; "constructive permission"
emphasizing what is laudable or hopeful or to the good; "constructive criticism"
necessarily or demonstrably true; "demonstrable truths"
capable of being demonstrated or proved; "obvious lies"; "a demonstrable lack of concern for the general welfare"; "practical truth provable to all men"- Walter Bagehot