I’ve come up with a formula
The amount of time a curriculum devotes to teaching critical thinking is inversely proportional to the actual critical thinking skills that the students acquire.
Think of it this way:
Critical thinking skills can only develop as the result of accumulated subject-specific knowledge, not as the result of learning “critical thinking” strategies in the abstract.
The more time students spend learning formal processes (e.g. identifying the main point) designed to teach them “critical thinking” skills in the abstract, the less time they spend obtaining subject-specific knowledge (e.g. biology, history).
Thus, the more time students spend learning learning formal processes designed to teach them critical thinking skills, the less likely they are to acquire the very knowledge that would allow them to think critically.
Or to put it in mathematical terms, where CT is defined as actual critical thinking ability and ct is defined as abstract, formal processes designed to promote “critical thinking:”