Constructing Morality: Transcendental Arguments in Ethics

How are moral claims justified? And is there an objective basis for morality? These fundamental questions of ethics are the central questions of this thesis. I explore and offer a partial defense of a so-called Kantian constructivist account of morality. I define Kantian constructivism as the position which (1) aims to justify moral objectivity (2) without relying on the existence of mind-independent moral facts through (3) an appeal to transcendental argumentation. I put forward this Kantian constructivism as an alternative to both moral realism, which is the view that moral objectivity depends on the existence of mind-independent moral facts (just as the objectivity of our empirical claims depends on the existence of empirical facts), and the method of reflective equilibrium, according to which moral justification depends on the coherence amongst our moral beliefs. Moral realism is the default position when it comes the metaphysics of moral objectivity, whereas reflective equilibrium is the default position when it comes to the epistemology of moral objectivity. I argue that both moral realism and reflective equilibrium face important problems, which motivates the exploration of the Kantian constructivist alternative. The argumentative strategy that I pursue throughout the thesis can be understood as an argument by elimination: I criticize what I take to be the most dominant approach to moral justification in ethics (the method of reflective equilibrium) and go on to evaluate to what extent existing transcendental arguments can succeed where reflective equilibrium fails, which, taken together, is meant as a defence of a Kantian constructivist justification of moral objectivity. The main focus of the thesis is on transcendental argumentation. There are many differences between specific transcendental arguments, but in general a transcendental argument works by asking the question of what is necessarily presupposed by understanding oneself as, for instance, a believer (in theoretical philosophy) or an agent (in ethics). A transcendental argument is thus a self-reflexive argument, and the point of the argument is to show that anyone who understands herself in a certain way is necessarily committed to whatever are the necessary conditions of the possibility of this self-understanding. The main part of the thesis evaluates existing transcendental arguments for constructivist moral objectivity in light of what I call the potential general dilemma for Kantian constructivism. The dilemma is that either the starting point of a transcendental argument is inescapable, but in that case no interesting moral conclusions can follow from the starting point, or Kantian constructivism succeeds in justifying interesting moral conclusions – but in that case the starting point turns out to be merely optional. I divide these ‘interesting moral conclusions’ into three categories: (1) success in justifying any categorical commitments at all; (2) success in justifying categorical and universal commitments, i.e. principles of interpersonal morality, and (3) success in justifying substantive moral commitments. I argue that although several existing transcendental arguments are susceptible to one or both horns of the general dilemma, an approach developed along Gewirthian lines is a lot more promising