No, really — how do you know?
I sat in on a class the other day when someone ventured what amounted to a faith-based argument that GDP growth is always good and decline always bad.
“How do you know?” demanded the professor.
“Uh, um … because it’s good?”
We never did get a satisfying answer. That doesn’t necessarily mean growth isn’t good, or even that it’s bad. But it does mean that skepticism is warranted toward received wisdom, premises, and shibboleths.
When the tools for blurring or slurring the truth get more sophisticated and widespread every day, the premium on knowing what you know and how goes up. A little reading or listening on epistemology can go a long way. Ask your “five whys.” Ask what could falsify your belief or change your mind.
Ask yourself constantly, “How do you know what you know?”