Sun and Mr. Allworthy are united, but with a difference: the sun, in all his majesty and splendor is, in the words of Boyle, "adiaphorous" unthinking matter, whereas Mr. Allworthy is a moral agent . . .
-- Jina Politi, The Novel and Its Presuppositions
. . .which participates of neither extreme, as for example, all those things which, as being neither good nor evil in themselves, we call adiaphorous, or indifferent.
-- William Watson Goodwin, Plutarch's Morals
Adiaphorous is derived from the Greek, adiaphoros, meaning 'indifferent.'