Ecclesiastes 2:3

2:3 I thought deeply about the effects of indulging myself with wine

(all the while my mind was guiding me with wisdom)

and the effects of behaving foolishly,

so that I might discover what is profitable

for people to do on earth during the few days of their lives.

Ecclesiastes 8:17

8:17 then I discerned all that God has done:

No one really comprehends what happens on earth.

Despite all human efforts to discover it, no one can ever grasp it.

Even if a wise person claimed that he understood,

he would not really comprehend it.