Heidegger's authenticity

To live with authenticity means to have principles and be true to them, Martin Heidegger seems to be saying.

You could live with authenticity as a nihilist but the presumption, if you are at all interested in philosophy - and Heidegger was a philosopher - is to live as a rational and moral human being. You cannot be said to be rational and moral if you are a nihilist ie someone with no principles unashamed of being unprincipled who cannot be trusted not to lie who cannot be moved by logic.

It would be a mistake to declare more principles than you are prepared to follow but it would also be a mistake to say you have no principles you care to defend.

So what principles have you, bearing in mind that to even be a successful criminal you would have to exercise logic?

Since most people cannot think these things through from scratch, they adopt a religion or a secular political ideology, but which moral system should we choose if we had to choose from scratch?

And would this be different to what we would choose as a nation?

Is living with authenticity knowing who we are and therefore what we are supposed to be doing?