This thesis discusses Ernst Tugendhat's concept of moral obligation and his account of why the only justifiable moral standard is universalism ("equal moral respect towards all"). The thesis is divided into two parts, and in the first I argue that Tugendhat presents a plausible idea of moral obligation as constituted by the "inner" sanctions of guilt and resentment. The propositional content of these reactive attitudes must refer to a moral standard, and this thesis provides an extensive discussion of Tugendhat's arguments as to why this standard must be universalism. There are some difficulties, but they can be solved within Tugendhat's own theoretical framework.
In the second part I consider criticism that has been levelled from two opposite camps: Jürgen Habermas agrees that universalism is the only defensible moral standard but denies that obligation is constituted through emotional sanctions. Peter Stemmer, on the other hand, agrees that moral obligation consists in emotional sanctions but rejects the claim that universalism can be justified. I argue Tugendhat's account can be defended against this critique and that both Habermas and Stemmer have incoherent accounts of moral obligation.