'Knows' in the Bible

Who knows whether he will be a wise man or a fool? Yet he will have rule over all of my labor in which I have labored, and in which I have shown myself wise under the sun. This also is vanity.

Who knows the spirit of man, whether it goes upward, and the spirit of the animal, whether it goes downward to the earth?"

For what advantage has the wise more than the fool? What has the poor man, that knows how to walk before the living?

For who knows what is good for man in life, all the days of his vain life which he spends like a shadow? For who can tell a man what will be after him under the sun?

for often your own heart knows that you yourself have likewise cursed others.

Who is like the wise man? And who knows the interpretation of a thing? A man's wisdom makes his face shine, and the hardness of his face is changed.