An English major with an accurate understanding of the sciences should certainly be allowed to teach to the level of his comprehension, though a science graduate should obviously be preferred. The real reason teachers fail their students is because most of them, 90% or more in my own district, would sooner cheat them out of a proper education than risk their careers to even a minimum extent. They concern themselves only with how they look to their overpaid administrators so that they, themselves, will one day be overpaid administrators. And so on, and on, and on...