Constructivism, Intersubjectivity, Provability, and Triviality

Sharon Street defines her constructivism about practical reasons as the view that whether something is a reason to do a certain thing for a given agent depends on that agent's normative point of view. However, Street has also maintained that there is a judgment about practical reasons which is true relative to every possible normative point of view, namely constructivism itself. I show that the latter thesis is inconsistent with Street's own constructivism about epistemic reasons and discuss some consequences of this incompatibility.