Sinnott-Armstrong's moral scepticism

Walter Sinnott-Armstrong's recent defence of moral scepticism raises the debate to a new level, but I argue that it is unsatisfactory because of problems with its assumption of global scepticism, with its use of the Sceptical Hypothesis Argument, and with its use of the idea of contrast classes and the correlative distinction between 'everyday' justification and 'philosophical' justification. I draw on Chisholms' treatment of the Problem of the Criterion to show that my claim that I know that, e.g., baby-torture is wrong, is no more question-begging than Sinnott-Armstrong's denial that I know this.