Answer:
There are two modes of mad scientists: "Promethean" and "Faustian".
'Promethean" mad scientist is the one who has good morals but fails because of human weaknesses whereas "Faustian" mad scientist is morally corrupted.
Explanation:
Robert Louis Stevenson composed a Gothic novella named "Strange Case of Dr Jekyll and Mr Hyde" or also known as Jekyll and Hyde. It was first published in 1886.
In the story, the good man, Henry Jekyll, one night goes to bed only to his own shock wake up transforming in the bad man, Edward Hyde.
"Yes, I had gone to bed Henry Jekyll, I had awakened Edward Hyde. How was this to be explained? I asked myself; and then, with another bound of terror—how was it to be remedied?"
Stevenson had presented the character of Jekyll having two personality, one of good, i.e., Henry Jekyll and the other evil, i.e., Edward Hyde.
An example of Jekyll's "Promethean" characteristics is found in his letter where he asserts that his split personality was because of his experiments and not his wickedness. And this is a human nature. That everyone has some good and evil, both, in them
“I, for my part, from the nature of my life, advanced infallibly in one direction and in one direction only. It was on the moral side, and in my own person, that I learned to recognise the thorough and primitive duality of man; I saw that, of the two natures that contended in the field of my consciousness, even if I could rightly be said to be either, it was only because I was radically both.”