I am not a philosopher, and any references to Plato are taken directly from this wikipedia article:

wiki/Platonic_epistemology

Thinking about Plato's Ladder of Love, it occurred to me that someone like Sherlock began at the top "rung" of knowledge, and to be a complete person, he's had to make his way down the ladder, away from the general and get down to the particular, "the most obvious form of love." I am woefully ignorant of Plato, so this is just my meandering take on it.

Down Plato's Ladder

Sherlock was a brilliant man. He had the brain of a scientist, a philosopher. The heart of a…did he have a heart? Born with such a "wondrous vision" of form, of knowledge, eternal and absolute. Lonely.

Mycroft. His first instructor. That king and queen of social order. Use knowledge for good, to serve the many. So noble a cause. So lofty, so cold. A distant philosopher king on his throne. Could he be? No.

Lestrade. The man of law, institution. Here was something that appealed. Sherlock was the keeper of knowledge, the light bearer, he had a responsibility to help maintain social order. The discord of his mind, the racing engine destroying itself could be harnessed to bring harmony to the world. Solve the crimes. Help the people—the people, the general, faceless mass of people.

John. Such a noble soul. A beautiful soul. A soul that woke within him the possibility of seeing the particular of people and not just the general. Has he ever known such a friend? No. Never has he known someone so specifically. Never has he admired someone so completely. A generous soul—has he ever been so generous, to anyone, to himself? He thinks not. John admires him, HIM, Sherlock, specifically. Sherlock begins to think he may have a soul after all, if one such as John could call him friend.

The Woman. The naked woman. The naked conniving woman, who sent him text after text each day, inviting him to "dinner." Reminding him that the body, all beautiful bodies, that sex existed. His libido was stirred. She was THE WOMAN, representative of her kind—sexual, manipulative, clever…oh yes, women were clever, weren't they and they were clever in such mysterious ways, such mysterious curves and mysterious crevices. They and their funny little brains, not so different from men, except for their cunning, silky bodies, round breasts and hips. The Woman? What is a woman. Much like a man. Clever, often, idiotic, often, but the body. Oh the body, it was different. Yes, THE WOMAN, attracting first his intellect, reminded him that he had a body. The Woman loved bodies. All bodies. Knew what they liked. Loved the idea of him and his body. Not that she got to touch his body. Not that he touched hers. She was an idea. A representation. One does not shag a concept. He saved the physical embodiment of this idea as it crouched in headlights on a cool night in Karachi. He was saving this new idea of woman, woman as a thing to be dealt with physically as well as mentally. He rather liked this new idea.

Molly. Oh, Molly. Molly the particular. Molly likes cats and floral prints. Molly who wields a scalpel and rib spreader with such skill. Molly holds his heart—she found it, such a skilled anatomist to find a heart where he was sure one did not exist. Molly the woman, the specific woman whose modest curves and oh, so cunning crevices he does explore so intimately. Clever Molly, physical Molly, loving Molly, who does not just love the idea of him—the dangerous, rude genius. Molly who loves all of him, the specific him, the small frightened Sherlock who cries when the emotions overwhelm, when he is scared of being alone and abandoned, of being ordinary. She loves the particulars of the Sherlock who loves honeybees and lots of sugar in his coffee. Sweet. She loves the Sherlock who once spent an entire year of his childhood calling himself "the dread Pirate Holmes," and who still sometimes calls his mother, "Mummy." Yes, THE WOMAN would have know that touching him just there would make him moan just so, but that was because she knew the body, all bodies, knew what bodies like. Of course, Molly knew all bodies as well—she was an anatomist, after all. But when Molly touched him just there, making him moan just so, it was because she knew HIS body and he knew hers, specifically, particularly, obviously.