NET
21 Who really knows if the human spirit ascends upward, and the animal’s spirit descends into the earth?”
Darby
21 Who knoweth the spirit of the children of men? Doth it go upwards? and the spirit of the beasts, doth it go downwards to the earth?
KJV
21 Who knoweth the spirit of man that goeth upward, and the spirit of the beast that goeth downward to the earth?