Rainer Forst’s constructivism argues that a right to justification provides a reasonably non-rejectable foundation of justice. With an exemplary focus on his attempt to ground human rights, I argue that this right cannot provide such a foundation. To accord to others such a right is to include them in the scope of discursive respect. But it is reasonably contested whether we should accord to others equal discursive respect. It follows that Forst’s constructivism cannot ground human rights, or justice, categorically. At (...) best, it can ground them hypothetically. This opens the door wide for ethical foundations of human rights. (shrink)