The Normative Web
The Normative Web (2007) by Terence Cuneo defends moral realism through a “parity argument”: moral facts and epistemic facts stand or fall together.
Core Idea
Cuneo argues that the reasons-for-belief studied by epistemology are themselves normative facts. So if you deny that moral facts exist, the same skepticism dissolves epistemic facts — leaving you with no reason to believe anything, including the denial itself. Rejecting moral truth is therefore self-undermining.
Why It Matters for Critical Thinking
A sharp reductio: it links the legitimacy of any reasoning to the existence of normative truths, showing that wholesale skepticism about “shoulds” quietly saws off the branch the skeptic is sitting on.