What determines at what proportion you need certain body parts and functions in order to qualify as "normal" for your species? Every time I talk to people who cannot describe someone else in a way other than saying that this or that person is "not normal," I have this aching desire to introduce them to the wonderful world of adjectives. I am quite aware that statistics would define "normal" as that which a majority of people have or are  the big bump of the bell curve. But there is something to be said about the importance of "being," far beyond the importance of simply being "normal." Whenever we talk about what makes us human, everyone has an opinion on it but I have not yet come across an opinion on what makes us NOT human. I think this is because we are only too aware of the big disparities in the way we all look and behave. We all know that being human is more than just about being normal, more than just being a coordinate in the hump of a curve.
Michelle Mack had a stroke very early. She had it while she was still in the womb so that her left brain never developed. I saw a picture of her brain scan in the website of Scientific American Frontiers and it was so flabbergasting  there really was nothing where her left brain should be. She had trouble with her visual-spatial abilities but she could talk, when what we know about the brain says it is the left brain that largely enables language. In fact, visual-spatial abilities are the mettle of the right side of the brain. Yet, Michelle is "whole" enough to work. She works for her church, charged with the computerized updating of their records. She also has an extraordinary talent in telling what any day of the week is from any date you tell her. It was Michelle who made me think about the meaning of halves (or portions) and what they have to do with the meaning of "wholes," not simply in the mathematical or anatomical sense, but when we reconcile our finite biology with our own humanity. I think we, the "normal" ones are really the ones impoverished when we refuse access to know what color is to the mind of the blind, what a song is to the deaf’s profound silence, or to how the taste of words play in the vocal cavity of a mute. We, the normal ones are the ones diminished for not being able to see that two halves are not the only ones that make a whole.
Next, I came across story of Tito Mukhopadhyay. Two days ago, I was reading a new book reviewed in the New York Times called "Strange Son" by Portia Iversen who wrote about Dov, now 15, his severely autistic son. She highlighted her life-changing encounter with Soma and Tito Mukhopadhyay, mother and son from India. I glossed over Iversen’s book review and went deeper into finding out more about Soma and Tito. Tito was born severely autistic and was non-verbal. His mother, however, showing grace but unflinching strength, found a way to make his son communicate through a letter board (which later became a keypad). Now, 19, Tito still looks like any severely autistic child but through his writings, you will see him. You will see him making you understand why he rocks and spins in a way that would blow your mind (below is an excerpt from http://www.halo-soma.org/about_writings.php?sess_id=91f52d804bb50b22108d2ba8855ed471):
When you are trying to think blue
And end up thinking black
You can be sure to be frustrated
Time and again it happens to me
And I get quite helpless
Otherwise why should I get up and spin myself
Spinning my body
Brings some sort of harmony to my thoughts
So that I can centrifuge away all of the black thoughts
I realize that the faster I spin
The faster I drive away the black
When I am sure that even the last speck of black
Has gone away from me
Then I spin back in the opposite direction
And pull the blue thoughts into myself
It depends on how much blue I want...
And this was only to express what he could do because he desired blue. Imagine what he could do with a rainbow.
Tito is a published poet. He liberated, in a way that great writers do, a mind like mine once caged in its own definitions. Now, I understand what all that spinning and rocking meant to them. I am not sure if Tito knows that it is also a "centrifuge" that is used to distill genetic material  DNA  from a cell sample. He even knew his physics intuitively and tried to use it to explain how he could separate the color he did not want from the color he wanted. In his autistic mind which normal ones doubt as "whole," he bridged art and science in a way that very few normal ones are successful and even beautiful, in achieving. He made them whole because he saw them whole.
To be normal is to never know blue as it dissociates from "black" in the centrifuge of a motion that Tito does. To be normal is to be doomed to speaking only when your left brain is present to configure it for you, unlike left-free Michelle. To be normal is to think normal is a sweeping human virtue. To be normal is to never know the whole of you.