In frankenstein how can you support that no one is completely good or completely evil

Victor Frankenstein was a promising young doctor and brilliant scientist. He had the potential to do much good for humanity (he wanted to cheat death), but he had a fatal flaw -- the pride, or hubris, which saw him creating a humanoid monster for his own glorification. Ambition and shortsightedness got in the way of commonsense.
The monster was also flawed--he murdered people,such as William and Elizabeth. However, at the end he reveals a human side. He is a tragic, pathetic figure, utterly lonely, miserable, and rejected by human society. He had wanted the normal human comforts of a wife and family but these were denied him by his creator who refused to make a wife for him.