Heidegger most heavily discusses “ethics” in “The Letter on Humanism,” a work responding to a series of questions posed by his French followers. One question was:
“What I have been trying to do for a long time now is to determine precisely the relation of ontology to a possible ethics.”
Here are some brief observations about his answer.
First of all, Heidegger rejects the distinction between “ethics” and “ontology.” “Ethics,” after all, comes from Plato’s academy, where philosophy was divided into “logic, physics, and ethics.” For Heidegger, the division of things into different “regions” means that “thinking” has disappeared and “science” has taken over, slicing “ethics” off as a separate region of study, something unconnected to Being. Remember, Heidegger isn’t interested in doing “ontology,” but something prior to ontology: raising the question of Being itself.
Accordingly, Heidegger goes back to thinking before this Platonic division, where philosophy wasn’t divided into independent categories. His primary source for ethics is Sophocles. He writes:
Thinkers prior to this period [Plato’s academy] knew neither “logic” nor an “ethics” nor “physics.” Yet their thinking was neither illogical nor immoral … The tragedies of Sophocles – provided such a comparison is at all permissible – preserve the ethos in their sayings more primordially than Aristotle’s lectures on “ethics.”
He discusses Antigone in detail in the lecture course Introduction to Metaphysics. He also discusses Heraclitus’ fragments in the “Letter on Humanism” in relation to “ethos” as well.
The Heraclitus fragment is three words:
“ethos anthropo daimon”
Heidegger translates these three words as:
“The (familiar) abode for humans is the open region for the presencing of the god (the unfamiliar one).”
He takes this from a story where some people went to see Heraclitus and found him huddle around the fire, shivering. The people who went to see Heraclitus were disappointed, thinking he’d be a guru who’d do something eccentric, something they could recount to their friends. Yet Heraclitus, bundled up before the fire, invites them in, saying (in Heidegger’s translation): “here too the gods come to presence (a translation of einai, which means “Being”).
For Heidegger, “ethics” is primarily connected to human “dwelling.” Dwelling, for Heidegger, is the human mode of “Being-in,” of existing within a world, of having a home. Yet this “home” houses the truth of Being. Heidegger likes a Holderlin poem that says: “poetically man dwells upon this earth.” Likewise, humans “dwell ethically.”
Heidegger’s “ethics,” accordingly, doesn’t treat classical ethical problems or even talk about “what is the right thing to do.” Rather, it thinks about the way that Being opens up a dwelling space, a city, a sphere for human action. Even huddling around the fire, “gods are here too.” As Heidegger writes:
“even here,” at the stove, in that ordinary place where everything and every circumstance, each deed and each thought is intimate and commonplace, that is, familiar, “even there” in the sphere of the familiar, it is the case that “gods come to presence.”
He thus concludes:
“If the name “ethics,” in keeping with the basic meaning of the word ethos, should now say that ethics ponders the abode of the human being, then that thinking which thinks the truth of Being as the primordial element of the human being, as one who eksists, is in itself originary ethics.
So basically, there’s a difference between the “thinking of human ethos” and the “science of ethics.” Heidegger isn’t interested in the latter, but the former.