The account that has been given of the relationships that derive from Mitsein may have made it sound as though they ensured a level of harmony and mutual respect of which, unfortunately, human history shows little trace. If that has happened, this chapter should put things in a more realistic perspective. Mitsein, after all, is not, in the first instance, an ideal; it is an ontological condition – what Heidegger calls an existentiale – and as such its reality cannot simply be abrogated by a violation of whatever normative requirements may turn out to be implicit in it. To put it in a different way, Mitsein is not just the form of our lives insofar as they conform to some ethical standard; it is a necessary condition for wrongdoing and evil as well.

This means that the concept of Mitsein must be shown to enable us to give an account of these negative realities of the moral life. The basis for such an account has already been laid. What is fundamentally unjustifiable and therefore wrong is to deny our distinctively human commonality with one another by treating someone as though he or she were not a partner in Mitsein and had no claim to any consideration in decisions we make about how to act.