An Enquiry Concerning the Principles of Taste, and of the Origin of our Ideas of Beauty, etc‪.‬

This is a philosophy book. You can no more define grace than you can happiness. The mind cannot so sted fastly behold it as to investigate its real properties. Grace is indeed the point of happiness in the ideal region, both because it arises spontaneously, without effort, &c. and because it seems partly within our own power, and partly without it. As common sense, in my fundamental circle, seems diffusive truth, so grace, in my ideal circle, seems diffusive sublimity; every perception of the former seems to be tinged, as it were, with the colour of the latter. Where pure grace ends, the awe of the sublime begins, composed of the influence of pain, of pleasure, of grace, and deformity, playing into each other, that the mind is unable to determine which to call it, pain, pleasure, or terror. Without a conjunction of these powers there could be no sublimity.