Like everyone else who's worked with autistic children, I have a theory about autism. I have no data and no real expertise, so I'm free to speculate.
First of all, I think it's really not one thing. It's probably several disorders of brain development, largely arising from genetic and intrauterine effects, that manifest with a few common features and many atypical features.
That's not all that interesting, so I'll go further. I also think that what's common in autism is the brain's frantic efforts to adopt to being broken. So one or many things is/are going "wrong" (quotes are important) in brain development, but there are common compensatory mechanisms that still work. The developing brain is breaking and trying to repair itself -- all at the same time. Somethings get repaired well, some don't. Sometimes the result works -- but it works differently.
Temple Grandin's mind works differently. Grandin is a famous interlocutor for autistic persons. She has several books and essays out, including this one: My Mind is a Web Browser: How People with Autism Think. Grandin has since recognized that she's really describing how she thinks, and that not all autistic persons think the same way . The point, however, is that she has an "alien" way to thinking. It doesn't work all that well most of the time, but it is well suited to certain types of problem solving. She is a visualization 'savant' , in a way that some autistic persons are numerical 'savants'. She has enough symbolic reasoning and language to be able to translate from her world of visualization to the more common world of language.
Variations in neurodevelopment resulting by "malfunction" and adaptation/healing, yielding diverse minds that function better in some environments, worse in others.
Remind you of anything?
Isn't that how natural selection works?
We think that humans haven't evolved much in the past few hundred thousand years because our bodies seem similar. We are creatures of the brain though. What if there's an adaptive advantage to a "flaky" neurodevelopmental process? Maybe there's a reason we have so many "malformed" brains. It's not only that brains are hard to make, but also that there's a species advantage to having diverse brains and minds being created - even if some individuals bear a heavy price for being maladapted to the common environment.
Perhaps if we truly understood the human mind, we would discover that we are much less alike than we think.
 Grandin is nothing if not definite, but she also changes her mind. It's an interesting trait, and very scientific in a way. Overgeneralizing from self to all is a classic autistic trait, and not uncommon in neurotypicals either.
 It would be interesting to see how well Grandin could talk to a dolphin, presumably they think in sonar.