Students and their teachers need critical thinking now more than ever. This is true not only because of the analytical challenges that critical thinking provides but also because of the social function that is served by civil discourse—that is, we must disagree without becoming disagreeable.
The essence of critical thinking is testing claims with evidence. Even very young children can, as Stanford neurologist Allison Gopnik reminds us, test hypotheses and tell truth from falsehood. Unfortunately, as children grow older, they confuse critical thinking with personal criticism and find the social cost of challenging assertions to be overwhelming. Adolescents in particular value consensus, and in some schools, the student who seeks the apparently reasonable middle ground may be prized over the one who vigorously defends a point of view with evidence.
Read more here