Correction please! I have just come through this sentence while reading an article: " The ideal culture, he writes, would provide both for a person’s physical needs and for the intellectual freedom to develop one’s selfhood. Most cultures and subcultures – political, religious, and social – fail to meet this tall order." . What does "tall order" mean here? Could it mean "unreachable aim"? And what other phrases would you use to deliver the same meaning? Could we say "this high order" instead of "this tall order"?