I've referred to spiritual autism before, but what is it, really?
One commenter here, Peter S., referred to it as a "more or less persistent and thoroughgoing numbness or insensibility with regard to the sacred." That's about as a sound a definition as one could hope for. Spiritual autism is a pervasive insensibility to the sacred.
A consequence of this insensibility is that reality and the order of being are improperly experienced. For reality itself is radically unfree: man's species, sex, race, nationality, time and circumstances of birth, and the authorities to which he is subject, to name just a few, are all determined for him without his consent or even his notice. In him, determinism reigns. With a strong sense of the sacred, this lack of freedom becomes understandable and rationalizable: through his participation in the sacred (for instance, by religious ritualism), man understands himself to be part of a rational order oriented toward the good. In other words, the sacred allows man to experience the authority of the order of being as legitimate. Without a sense of the sacred, reality becomes meaningless, senseless, and incomprehensible; the human condition becomes one not of citizenship and duty but of imprisonment and injustice. Rebellion against that order results, with predictable consequences.
Where does spiritual autism come from? In part, from simple ignorance (what Musil called "honest stupidity," that is, man's natural inability to comprehend the sacred in its fullness, compounded by general societal ignorance and a lack of religious tradition). In part, from sin, which deadens the conscience and weakens man's spiritual faculties. And in part from an intentionally disordered will: from a will to disbelieve. This will to disbelieve leads man to folly, especially when confronted with flatly incontrovertible rational arguments for, say, the instance of God: it leads him to believe that the universe is disorderly, that anything can come from nothing anywhere and at any time, that reality itself is socially constructed, that there is no necessary connection between effect and cause, that one man is not necessarily any more like another man than a starfish is to a skyscraper, and so on. It is a temptation, as old and as evil as the serpent that inspired it.
The will to disbelieve may well be the most important aspect of spiritual autism, and it corresponds to earlier thinkers' and societies' tendency to diagnose it as simple folly (the Israelite nabala, the ancient Greek amathia, the Scholastic stultitia, and Robert Musil's "higher stupidity"). The will to disbelieve is what turns mere incompetence to apprehend the sacred into an actual sin, born of pride and committed with the full assent of the will. It is what makes it a damnable, instead of a merely regrettable, thing.
We must not make the mistake of thinking that spiritual autism is exclusively a feature of atheists (though I have yet to meet an atheist that didn't exhibit the intentional affectation of ignorance or the rank hubris of the pneumopath). Nearly all modern theists exhibit it, as well, especially among the creedal Protestants, who have collapsed almost completely into modern liberalism. (Jim Kalb's description of the Episcopalian Church in Pennsylvania where the Stations of the Cross had been replaced with stations of the UN Millennium Development Goals at the start of his talk "PC: The Cultural Antichrist" really drove this home for me). In the Catholic Church, where a culture of widespread dissent has crystallized that is urged on by the feckless and timid response of the hierarchy to open heretics among the clergy, virtually nobody knows about, cares about, or understands anything the Church teaches, especially with respect to moral theology. It is simply seen as unimportant, faith itself as an adornment to an otherwise wholly worldly life, to be ignored or discarded when inconvenient.
I call this phenomenon "spiritual autism" not because it is a naturally-occurring defect (being a defect of the will and spirit, it obviously isn't) but because this defect produces the kind of insensibility to complex phenomena commonly seen among people with Asperger's. Reductionism is one common feature, whether the epistemological reductionism of modern scientists, individualist reductionism of modern political thinkers, the religious reductionism of pseudo-Christians, and so on. The kind of bland and blinking misapprehension, embarrassingly persisted in even when pointed out, is another. Edward Feser's kerfluffle with Stephen Law over the latter's absurd "Evil God Challenge" to classical theism is a pretty good example of this. At one point in the ensuing discussion in the comments section, Feser points out that the challenge is inapplicable to classical theism because an "evil God" is an ontological non sequitur, a metaphysical impossibility, whereupon Law replies that this is no reason to suppose his argument is invalid! Deeply confused, irrational, disordered thinking about matters metaphysical prevails among the spiritual autists, and this confusion penetrates literally everything to which they turn their attention. Eric Voegelin's terming it pneumopathology -- spiritual insanity -- may be more apt.
I think spiritual autism is largely unrepentable, although miracles are, hypothetically, always possible. The man who has genuinely convinced himself that the universe is a chaos and being a prison has a long, long way to go before his soul may be saved. He is mired in darkness, squalor, and ignorance. Perhaps nothing short of a truly heroic exertion of grace may be able to turn him away from his follies.