Prof. Brian Bingham during the MetaOlin Systems Engineering module: "All models are broken."
Then later that night, Eric Munsing lent me a copy of Thich Nhat Hanh's book Being Peace, and I read the following (from the precepts of the Buddhist order Nhat Hanh belongs to):
First: Do not be idolatrous about or bound to any doctrine, theory, or ideology, even Buddhist ones. All systems of thought are guiding means; they are not absolute truth.
Made me smile.