the reason... madness. in order to know the reason (or cause) of folly's wickedness, and the madness of folly.
Related Commentaries of Ecclesiastes 7:25
Ecclesiastes 7:25
25 I appliedi mine heart to know, and to search, and to seek out wisdom, and the reason of things, and to know the wickedness of folly, even of foolishness and madness: