The Idea of Reason in Piers Plowman.
ME resoun, which has undergone significant semantic change, more closely corresponds in meaning to Lat. ratio than to ModE reason. WL shares the prevalent medieval attitude that law is an act of the intellect, a norm of right independent of the will, and hence to be equated with Truth. When brought within the scope of human psychology, this norm is called “natural law” (B.1.142). Ratio, however, refers both to that which is apprehended as truth or eternal law and to the faculty of mind that apprehends it. WL distinguishes resoun or ‘transcendent order” (as in the recurring pleonasm “reason and right”) from wit or kynde wit, the power of the individual rational intellect. The word resoun also includes a strong numerical component (ratio in the sense of’ reckoning’) that embraces the idea of compensatory justice. In its three major appearances in the poem, Reason functions as a moral absolute, first identified with secular power as an adviser to the King in the trial of Wrong and Lady Meed (where Reason as retributive justice cannot forgive, although Peace is willing to drop the charges). Second, Reason is associated with ecclesiastical power, in his sermon to the various estates in admonishing them to fulfill their particular obligations (B.5). Third, he is associated with Nature itself (B.11.324-404; C.13.128-213) where WL draws the conventional contrast between animal behavior, which conforms to natural law, and human behavior, which often does not. When Will absurdly blames Reason for this state of affairs, his criticism is directed more at the divine order than at the mental faculty by which we subjectively perceive it.
Kennedy et al., Medieval English Studies Presented to George Kane, 199-215.
Alford, John A.