How does Arthur Conan Doyle differentiate Watson and Holmes in The Sign of Four?

Dr. Watson's romantic attachment to Mary Morstan is crucial here. We simply can't imagine, in a million years, that someone as coldly logical and rational as Sherlock Holmes would ever give his heart to a woman the way that Watson does to Mary. Watson is presented to us in The Sign of Four as an unabashed romantic, a man who follows the dictates of his heart. Holmes, on the other hand, is concerned purely and solely with what is logical. And what could be less logical than love?

Because Watson is much less devoted to cold, hard facts than Holmes, he's pretty useless when it comes to solving this particular mystery. But his romanticism does have the advantage that it provides much-needed emotional support to Holmes as he goes about his ace detective work. Holmes may not care to acknowledge the fact, but he needs the loyalty of his friend in much the same way that Watson needs the love of a good woman. The two men may be completely different in so many crucial respects, but they share similar needs, and it's their respective ability to fulfill those needs that makes their relationship such a strong one.

Conan Doyle presents Sherlock Holmes as a person whose main mode of perceiving and understanding the world is logical and factual, whereas Dr. John Watson perceives the world primarily through his emotions. Watson is actuated and motivated by loyalty, friendship, and love, including his love for Mary Morstan, and by loyalty and friendship towards Holmes. Holmes, however, primarily needs the stimulation that puzzles and problem solving provide, which is why he has become a detective. When he does not have a case to occupy his mind, he takes cocaine.

As a doctor, and because he cares about his friend, Watson is appalled at Holmes's cocaine habit, which he fears will harm him. For Holmes, however, mental stimulation is at the heart of what makes life meaningful to him, and if can't get through his work, he gets it through a drug. As he says to Watson:

I abhor the dull routine of existence. I crave for mental exaltation.

Holmes criticizes Watson for adding love and emotion to his stories about Holmes's cases:

Detection is, or ought to be, an exact science, and should be treated in the same cold and unemotional manner.

Watson, however, argues that if love or emotion are part of the story, they should be included. This typifies the difference between the two men: Holmes leads with the head, Watson with the heart.

How are Watson and Holmes portrayed as different male characters in The Sign of Four?

At the beginning of The Sign of Four, it is clear that Sherlock Holmes intimidates John Watson. Although Watson is a doctor and a war veteran and quite accomplished in his own right, Holmes's confidence and intelligence make Watson reluctant to confront him about his drug abuse. Watson endures Holmes's egotism; he is fascinated by Holmes's powers of deduction and the adventures his work provides for both of them.

Holmes is not especially skilled in interacting with other people. He tends to be tactless, uninterested in others, and insensitive to others' feelings. He does not mean to give offense but frequently accomplishes just that. Watson, on the other hand, is attuned to the feelings of others and provides a buffer when Holmes is interacting with clients and suspects.

It is no surprise, then, that Watson should strike up a romance with Miss Morstan and end up engaged to her. When Watson announces the engagement to Holmes, he groans and tells Watson he cannot congratulate him because

love is an emotional thing, and whatever is emotional is opposed to that true cold reason which I place above all things. I should never marry myself, lest I bias my judgment.

Instead of taking offense, Watson is able to laugh and accept his friend and colleague's lack of social skill.

How does Conan Doyle present Holmes as unique in "The Sign of Four"?

Sir Arthur Conan Doyle introduced readers to Sherlock Holmes, the masterful detective skilled in the art of deduction, in his first novel, A Study in Scarlet. Doyle’s second novel, The Sign of the Four, works to add depth to the character of Holmes and helps to cement him as unique, specifically through his drug use and his inability or unwillingness to marry.

In The Sign of the Four, a complex plot unravels surrounding a stolen treasure from India and an unlikely alliance between four criminals and two prison guards.

When not actively solving a crime, Holmes often partakes in illicit drug use, chiefly cocaine. The assumption is that a detective would be obsessed with upholding the law and that any illegal drug use would be avoided in accordance with the law. However, the reader comes to understand that Holmes is not obsessed with uploading the law; instead, he is obsessed with uncovering the truth through the art of deduction. When his mind is not actively consumed on an active case, he finds other ways to achieve a similar stimulus. This serves to add incredible depth to his character.

At the end of the novel, the reader learns that Watson proposes to Mary Morstan and that she accepts. This is used to juxtapose the Holmes's nature as a bachelor. Instead of dedicating his life to a marriage partner, the reader understands that he has already dedicated his life to the art of deduction.