  Nathan Ballantyne and Joshua C. Thurow (2013) maintain that this argument does not work. They outline their point in terms of undercutting defeaters and defeaters of those defeaters. The distorting factors that Sinnott-Armstrong mentions are the undercutting defeaters of the justification of most of our moral beliefs. If we have evidence that a subclass of our moral beliefs is not subject to these undercutting defeaters, then that evidence defeats the defeater, and justification is restored.