but to feel, on our part, some sentiment of blame or approbation;
whence we pronounce the action criminal or virtuous.

III. This doctrine will become still more evident, if we compare
moral beauty with natural, to which in many particulars it bears
so near a resemblance. It is on the proportion, relation, and
position of parts, that all natural beauty depends; but it would
be absurd thence to infer, that the perception of beauty, like
that of truth in geometrical problems, consists wholly in the
perception of relations, and was performed entirely by the
understanding or intellectual faculties. In all the sciences, our
mind from the known relations investigates the unknown. But in
all decisions of taste or external beauty, all the relations are
beforehand obvious to the eye; and we thence proceed to feel a
sentiment of complacency or disgust, according to the nature of
the object, and disposition of our organs.

Euclid has fully explained all the qualities of the circle; but
has not in any proposition said a word of its beauty. The reason
is evident. The beauty is not a quality of the circle. It lies
not in any part of the line, whose parts are equally distant from
a common centre. It is only the effect which that figure produces
upon the mind, whose peculiar fabric of structure renders it
susceptible of such sentiments. In vain would you look for it in
the circle, or seek it, either by your senses or by mathematical
reasoning, in all the properties of that figure.

Attend to Palladio and Perrault, while they explain all the parts
and proportions of a pillar. They talk of the cornice, and
frieze, and base, and entablature, and shaft, and architrave; and