On the Sublime and Beautiful/Part III/Chapter 21

IT may perhaps appear like a sort of repetition of what we have before said, to insist here upon the nature of ugliness; as I imagine it to be in all respects the opposite to those qualities which we have laid down for the constituents of beauty. But though ugliness be the opposite to beauty, it is not the opposite to proportion and fitness. For it is possible that a thing may be very ugly with any proportions, and with a perfect fitness to any uses. Ugliness I imagine likewise to be consistent enough with an idea of the sublime. But I would by no means insinuate that ugliness of itself is a sublime idea, unless united with such qualities as excite a strong terror.