NET

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.

Darby

17 then I saw that all [is] the work of God, [and] that man cannot find out the work that is done under the sun: because however man may labour to seek [it] out, yet doth he not find [it]; and even, if a wise [man] think to know [it], he shall not be able to find [it] out.

KJV

17 Then I beheld all the work of God, that a man cannot find out the work that is done under the sun: because though a man labour to seek [it] out, yet he shall not find [it]; yea further; though a wise [man] think to know [it], yet shall he not be able to find [it].