You'd be a little puzzled, because this definition gets us no closer to what a heart attack is, what is happening in the body.
So you ask, what's the cure?
I answer, well, we've trained all the patients out of rubbing their arms and moaning, but they keep falling over whatever we do. I guess the only solution is tying them upright!
That's kind of where we are on autism. It's described and defined, not by the interior workings of the mind, but by the most noticeable symptoms: social problems, stimming, meltdowns. And the available therapy, which is mainly ABA, focuses entirely on extinguishing behaviors rather than making the person feel any better. They teach social skills and train a child out of stimming, but weirdly the meltdowns only get worse. Or the person starts experiencing anxiety and depression. We know autistic people, especially those considered to be "high functioning," have an elevated suicide risk.
This way of defining autism also keeps girls from being diagnosed. We know that autistic girls are better at mimicking appropriate social skills. So people say, well, that's not autism then. Autism includes poor social skills, so if this girl has figured them out on her own, she can't be autistic.
Women also react to heart attacks differently, but in this case we are told that heart attacks may not involve arm pain and to learn the signs of heart attack in women. What if we considered autism the same way? Rather than saying "the symptoms are different, therefore it can't be autism," maybe we should ask what the symptoms of autism look like in women.
I don't think I can clearly and briefly define autism from the inside. I can say, for sure, that there are sensory processing differences. And that autistic people's brains seem less generalized; they'll often be overpowered in one area and underpowered in another. These two things cause social problems, because social skills require coordination of a lot of different skills at once, and most autistic people will have trouble with at least one of those. But some autistic people will learn to manage the social skills problems early on, and thus be overlooked at truly autistic.
I'm a believer in autism research. Unfortunately, most of the research being done right now is focusing on all the wrong things: either how to extinguish behaviors, or what causes autism in order to prevent it. The first is a problem because changing behaviors doesn't cure autism, and may make a person feel much worse. The second is a problem because autism is almost always genetic, and the only "cure" for genetic ailments at this point is abortion. So while there's nothing wrong in theory with pinpointing specific genes, it becomes a massive problem when people are so scared of having an autistic child they'd demand prenatal testing for it.
Instead, the research I would like to see is more about what is specifically happening in the brain. What does overstimulation look like, and what helps? What interventions actually work in lowering anxiety and stress in the brain? Marko has just turned a corner from a four-month bad spell where he was angry and explosive all the time, and suddenly he's happy and excited again. He's just as autistic as before, but something did change. Could science help us understand what flips this switch in Marko and how to give him more good days?
Unfortunately, society just isn't there. Most people still see an autistic child demanding a green shirt every day or flapping their hands and say, "How do we make them look and act like a neurotypical child?" They're not asking how to help an autistic child live their best life. And until the people giving the money, organizations sponsoring the research, scientists, doctors, and therapists are all centering the well-being of the autistic person, we're not going to make much progress.