Early in Nietzsche’s Thus Spake Zarathustra, the fictional prophet says, “I conjure you, my brethren, remain true to the earth, and believe not those who speak unto you of superearthly hopes!”
Nietzsche was talking about being true to some chosen belief system in the face of the bankrupt morality provided by religious faith. He wanted the body to do all the talking. In his parable, Zarathustra literally descends from his solitude on a mountain to re-enter civilization, to once again become a man.
I don’t know the origins of the phrase down to earth, but a down to earth person is not caught up in privilege and posturing, just as Nietzsche’s superman (übermensch, overman) is not hiding his head in the sands of virtue and its twin, complacency.
Some ecocritics have taken Nietzsche as their own based on this “remain true to the earth” phrase. Some of us will not read Nietzsche in this way, but nowadays, many of us remain true to the earth (and ourselves) by planting seeds in it; a few of the most secure and happy people I know are farmers.
And lately, a spate of movies—Avatar, Wall-E, The Lorax— have paid tribute to the earth. In the latter two, the saving of a plant and its climactic sprouting is the ushering in of a new/old dynamic: humans and the soil, labor and (literal) fruits, sweat and sustenance.
Of course, by now our soil is depleted; from it, life springs cautiously and with less abundance and nutrition. Now, dirt-free vertical gardens also bring us back to earth in a different way, and those involved in that upward propagation are heroes, giving us new systems to provide non-corporate, non-GMO food.
This food is the moral compass in a Godless, compass-less world.
And, good grief, Nietzsche should have hiredeth himself an editor.