There is no purer expression of the objectivity of value than G. E. Moore's in Principia Ethica. We can best capture the purity of Moore's vision by reaching across the ages to contrast him to the philosopher with whom he shares the deepest affinities, Plato. Plato trounces both the logic and psychology of Thrasymachus's confused and callow diatribe that the notion of objective value is based on a hoax. Still, there are times when one wonders whether he is just saying how he would manage the hoax were he in charge. Even if Plato's giving great lines to skeptical opponents is finally not an expression of unease, but of supreme confidence in the power of his thought and the beauty of his poetry to overwhelm the gravest of doubts, this comparison highlights the fact that in Principia, Moore never even entertains doubts about the objectivity of value. It is not outright skeptics who catch Moore's ire, but philosophers who refuse to serve objectivism straight.

J. M. Keynes points in the direction of this fact about Principia in his loving and clear-eyed memoir when he speaks of Moore's innocence. How a man of thirty, especially one who kept the company Moore did, could have remained innocent is a mystery difficult to fathom. Perhaps it is to be savored rather than solved. Likely, it is no part of its solution but only another way of pointing to the mystery to observe that Moore seems to have been utterly lacking in irony.