What We Can't Not Know: A Guide.
"Deep conscience, Budziszewski asserts, is an 'interior witness'. While it defies a pinpoint definition, it is 'the reason why even a man who tells himself there is no right and wrong may shrink from committing murder'. The author differentiates between this deeper, inborn conscience, and the surface conscience that is the primary cause of guilty feelings. He states that 'deep conscience is knowledge, not feelings, and guilty knowledge darkly asserts itself regardless of the state of the feelings'."