Final answer:
People found Mr. Hyde ugly because his ugliness was internal and stemmed from his evil character rather than his physical appearance. The literary theme highlights the duality of human nature and suggests that true monstrosity comes from within.
Step-by-step explanation:
Although people found Mr. Hyde ugly, they could not explain why because his ugliness was not physical. It did not stem from his facial features or his appearance in any conventional sense, but from a deeper, intangible essence. This concept of internal ugliness transcending physical features is recurrent in literature that explores the theme of the monstrous nature lurking within human beings, disguised under a veneer of respectability. Characters like Mr. Hyde in Robert Louis Stevenson's novel often symbolize the evil and moral corruption that can hide beneath a commonplace exterior.
In literature, authors frequently contrast the external physicality of a character with their internal moral qualities to illustrate that true ugliness or beauty comes from within. This exploration often reveals how society's superficial judgments can be misleading, as the true nature of a person's character can be masked or betrayed by their physical presentation.