> If I had to guess, I'd say it's based on the fact that math involves a lot of critical thinking and critical thinking is very difficult to teach.
I don't think critical thinking is very difficult to teach.
I think critical thinking is, despite being foundational, not prioritized in most educational curricula (and, particularly, not in most of the high-stakes testing regimes which we use to evaluate students, schools, teachers, etc.), and consequently insufficient effort is put into teaching it.
Critical thinking is not prioritized because it is hard to evaluate.
Due to the demand for teacher accountability, the insane level of competition for college entry, and the political games surrounding education policy, modern public education is entirely centered around examination and evaluation.
Not only is critical thinking challenging to evaluate, but, more importantly, people—read, parents—do not accept evaluations that report bad critical thinking skills. If a child can't answer 2 + 2 or who President Washington was, then they clearly didn't know. But if you ask a question that truly challenges critical thinking skills, and the child receives a bad score, the parents will be marching into an administrator's office with complaints of "trick questions" and "unfair grading". And fear of parent backlash drives American public school administration's decision making.
> Critical thinking is not prioritized because it is hard to evaluate.
I don't think that's the root cause for why its never been considered a core skill and treated (when treated at all) as sort of an optional additional skill usually addressed, if at all, late in schooling as part of the English curriculum.
But I do think that's an additional challenge to getting it treated as a core focus in today's testing-obsessed public education context.
I think critical thinking is the opposite of what most schools want to teach. Take Khan Academy founder's book [1] which describes the mainstream "Prussian Model":
"The idea was not to produce independent thinkers, but to churn out loyal and tractable citzens who would learn the value of submitting to the authority of parents, teachers, church, and ultimately, king. The Prussian philosopher and political theorist Johann Gottlieb Fichte, a key figure in the development of the system, was perfectly explicit about its aims. 'If you want to influence a person,' he wrote, 'you must do more than merely talk to him; you must fashion him, and fashion him in such a way that he simply cannot will otherwise than what you wish him to will.'"
Chomsky further discusses the important role of "stupidity" in the educational system (like stupid assignments), in teaching obedience: (http://www.youtube.com/watch?v=pFf6_0T2ZoI)
I don't think critical thinking is very difficult to teach.
I think critical thinking is, despite being foundational, not prioritized in most educational curricula (and, particularly, not in most of the high-stakes testing regimes which we use to evaluate students, schools, teachers, etc.), and consequently insufficient effort is put into teaching it.