Arthur Conan Doyle himself once described his most lasting creation as a man without a heart, being brain only. Most actors have approached the man with this in mind, and it has crippled most portrayals of him, reducing him to a reasoning machine with only one fallible human quality: egotism.

Granted, when one reads the Doyle canon, egotism emerges as one of Holmes's most salient qualities. He's bright, very bright -- and he knows it. He's also relentlessly logical, and given that, his egotism could simply be nothing more than a reasonable estimation of his own mental acuity. Even that one emotional failing could simply be reduced to being an offshoot of logic and intellect, thus rendering him completely barren of fallible, human passions, without even that one failing.

And yet there is the man who cares for his friend and who reveals himself as more than willing to be excited about this or that when it intrudes upon a case. He smiles, he laughs -- and despite Watson's judgement that he only laughs when it bodes ill for someone, much of his laughter and delight is not thus provoked.

There is the man who disapproves of cruelty, revealed over and over in his cases despite the fact that it may have no bearing on anything. There is the man who can inspire dedication, affection, and loyalty out of someone with a very well-developed repertoire of emotion, John Watson. There is also the artist, the unparalleled musician. Such a soul couldn't exist without emotion, indeed very profound emotion.

Which begs the question: why would someone with profound emotional depth impress upon everyone around him that he is nothing so much as a cold fish, the sort of man who lowers the temperature of any room he enters? Why, if he is emotional, does he seem not only unwilling but unable to express it? Is he the heartless man he is claimed to be? Isn't it within the realm of possibility that he is indeed a cold fish, inspiring loyalty out of Watson simply because Watson is deluded as to his value?

Perhaps only because Watson comes across himself as wiser than he realizes and fairly good as estimating people, we may safely believe that this is not the case, and that the flashes of humor and tenderness that Holmes sometimes doles out, along with his artistic expression on the violin, aren't merely aberrations or sops with which to satisfy Watson's humanity, but spring from some deeper place in his mind, and even his heart. If we consider our own emotional reactions to the things that go on around us every day, we can arrive at a reasonable estimation of Holmes as not simply an emotional being, but as one who may feel emotions in a much more profound way than most people.

Consider your own reaction to excessively emotionally jarring news. Perhaps you learned that a friend had been the victim of a violent crime, or perhaps (and I do not mean any disrespect by bringing this up in what is only an essay on fiction) you noticed for the first time that the old gentleman living next door to you has a serial number tattooed on his arm. How do you react to this? How do you think that most people react?

Some people, those who are what I call left-lobe-heavy, or "T" type personalities on the Keirsey scale, often reflexively wish to run their emotions according to what they feel are sensible lines. Not that they wish to control them, but they prefer to be logical about their emotions. And when confronted by a situation which seems to provoke an extreme emotional reaction, they are not certain how to respond. Desiring to express the "sensible" emotion in an appropriate way, they can often hang up when confronted with things that literally have no appropriate response. Even those who are not so firmly ruled by rationality can feel as if words of sympathy sound flat and inadequate in highly charged situations.

And so the rational person believes that a situation that evokes extreme emotion merits an extreme emotional response. For a situation in which no response could be extreme enough to be adequate, the result is no response at all. To paraphrase the old saw, "If you can't think of anything appropriate to say, don't say anything at all."

What then happens when the excessively rational person is also excessively emotional? What happens when someone who feels deep and powerful emotions in response to very little, is also someone who is equally powerfully under the rule of rationality? Despite the tendency to categorize people as either exclusively "logical" or "emotional," excesses (or lacks) of both in any relative quantity can be found in anyone.

Such a person may find themselves equally at a loss when discussing the death of a family member or the failure of a parcel to arrive on time. Such a person would have a very low threshold for "expressive paralysis."

And given that humans are social creatures and very sensitive to the reactions of others around us, the constant awareness of one's "inappropriateness" would cause the rational person of deep emotion to suppress any and all emotional expression.

Such is the case with Holmes. Excessively rational, he might wish to express himself with all the extravagance that tragedy demands when Helen Stoner confesses the death of her sister to him. He might feel a tremendous upwelling of emotion at the revelation that Carruthers and Woodley thought so little of his client that they would play cards for her possession. He might hate Stapleton strongly for his ill treatment of his wife.

And being that such deeds would rouse an excess of emotion in him, he would feel any expression of the emotion to be inadequate to the task.

We each have our emotional "tripwires" strung at different heights. A broken nail evokes less emotion than a lost package in the mail, which evokes less emotion than a car accident, which evokes less emotion than the death of a dear friend.

What happens when all such events evoke equally strong emotion, when the "tripwire" is strung far too low? And when the person feeling it is keenly aware of the rational inappropriateness of such strong reactions?

They are suppressed, powerfully. Thus my supposition that Holmes's own emotional tripwire is strung so incapacitatingly low that he has learned that he must "tune it out" in order to function.

People with autism often appear insensitive and withdrawn from the world around them. In reality, their nervous systems are overly sensitive, such that the slightest touch from the outside world sends an avalanche of sensation gibbering through them. They withdraw in reaction, removing themselves from what seems a painful sphere of interaction -- the world at large. In result, these most sensitive individuals in the human race appear the most sensually dead. Holmes can be said to be a subtle emotional autistic, so powerfully affected deep inside himself by the events around him, particularly tragic ones, that he avoids all interaction save that which permits him to control the events, and thus mitigate their effect on him.

And his one friend, Watson, is the one man who has never tried to provoke a reaction from him -- has left him alone to his emotional core, has not tried to touch him and thus send him into withdrawal. When Holmes -- at his most sensitive -- voluntarily withdraws, Watson leaves him alone, lets him come out of it on his own, instead of attempting to break through the walls, causing Holmes to fortify them further in a feedback loop that would result in his being absolutely encased in emotional cement.

Watson's passivity and patience -- his willingness to contentedly wait out Holmes's withdrawals -- has permitted Holmes to send out the occasional emotional feeler toward his friend, has permitted him to hazard tentative steps outward from his enforced isolation, knowing that he will not be deluged with a response that he can't deal with. He can wet his toes around Watson without fearing that it will be met by a response that will trigger a withdrawal on his part.

Thus, it is clear that not only does Holmes's emotional autism explain his apparently aloof behaviour in the canon, but it also explains his long relationship with Watson, the one person who treated Holmes exactly how he needed to be treated.