To conduct his investigation of human achievements Solomon had employed the tool of wisdom.27However, he discovered it inadequate to turn up any meaningful activity. Consequently wisdom was in this respect no better than "madness and folly"(v. 17; i.e., foolish ideas and pleasures).
". . . in Scripture both madness' and folly' imply moral perversity rather than mental oddity."28
Greater wisdom had only brought him greater "grief"(mental anguish) and "pain"(emotional sorrow, v. 18).
The phrase "I perceived"and its synonyms occur frequently in Ecclesiastes (cf. 1:13; 2:1, 3, 14, 15; 3:17, 18, 22; 7:25; 8:9, 16; 9:1).
"Heart' points to the combined use of mind and will in the quest for knowledge. Biblical Hebrew has no specific words for mind or brain. Thinking and understanding and deciding are all done by the heart.'"29
