I am frustrated when reading that article because it tells me I should doubt a certain set of assumptions but doesn't describe in detail the assumptions it wants me to use to replace those assumptions. "Doubting" in a vacuum is pretty difficult to do well, it's better to create many different ideas and then compare and contrast their strengths and weaknesses.
Quotes are a unique enough medium of expression that I'm interested in viewing quotes that people have found collectable, emotionally impactful, useful, memorable, or otherwise noteworthy - perhaps others are similarly interested. To clarify, these need not be even remotely related to rationality. I'm hijacking the mandates traditionally used for the Rationality Quotes thread, with a few modifications:
Please post any meta discussion in the top-level comment named "Meta".