In The Strange Case of Dr. Jekyll and Mr. Hyde, what is the role played by Mr. Utterson?
Mr. Utterson plays a singularly important role in The Strange Case of Dr. Jekyll and Mr. Hyde. As the one through whom Stevenson focuses the reader's attention on this strange case, Utterson's consciousness is the vehicle through which we learn the story. Stevenson has taken care to characterize Utterson as a man who is not judgmental and who is a fair observer. In other words, Utterson is a reliable narrator whose own emotions won't impinge upon the events or the telling of events.
Along with his role of reliable narrator, Utterson is like the something that shines from his eyes and stands in contrast to both Jekyll and Hyde, which positions him as the measuring stick by which to measure what is truly deficient in both Jekyll and Hyde. Does the deficiency stem from Jekyll's brooding nature? No, because Utterson is also brooding. Does it stem from his aloof analytical scientific mind? No, Utterson also has an aloof analytical mind, though of legal training. Jekyll and Hyde are deficient in the most valuable quality Utterson possesses, and that is humanity.
Stevenson writes that there was "something eminently human" shinning out of Utterson's eyes. This is never said of Jekyll--and certainly never said of Hyde. Therefore Utterson's primary role, along with that of reliable narrator, is to show that temperament isn't Jekyll's deficiency; it is his lack of humanity that is his deficiency, and Hyde is the personification, if I may borrow a term, of Jekyll's inhumanity. How does Stevenson define humanity? He defines humanity by Utterson's qualities: compassion, loyalty, nobility, reasonableness, trustworthiness, a giving soul, an embracing nonjudgmental soul. These are the things which Jekyll lacks. These are the things of which Hyde is the antithesis.