Question

What is the meaning of heresy, and how do both Henry Jekyll and Robert Louis Stevenson exhibit it?

Answer 1

Answer: Heresy is often a controversial or unorthodox opinion held by members of a group. While Henry had more radical views, Stevenson was more driven by morality and as opposed to Henry, there's little heresy in his works.

Explanation: Heresy are opinions that are significantly at odds with whatever principles or doctrines that is generally accepted.

Henry Jekyll was said to have had more radical behavior, favoring fundamental change with orientation that was more towards every other opinion that contrasts his. With a zeal for morality was Stevenson and yet heresy as we know it is still not very much present in his work. The strong presence of morale becomes the very essential for the absence of the heretical views. The presentation and study of these two individuals becomes radical in ways but definitely not heretic.

Answer 2

Heresy is a belief or opinion contrary to orthodox doctrine.
Henry Kekyll wasn't so much heretic as his views that were radical, but his behavior. Instead of having a coherent philosophy of his own, he was self-centered to the extent of wishing ill on anybody who was not pandering to him. 
Robert Louis Stevenson was very much the complete opposite of Henry Jekyll. There is a strong sense of morality infusing Stevenson's stories. But even among this, I would still call Stevenson a moralist rather than a heretic. I hope this helped.