Seek independent confirmation of alleged facts. Encourage an open debate about the issue and the available evidence. "In science, there are no authorities. At most, there are experts." Come up with a variety of competing hypotheses explaining a given outcome. Considering many different explanations will lower the risk of confirmation bias. Don't get too attached to your own ideas, lest you get reluctant to reject them even in the face of evidence to the contrary. Quantify whenever possible, allowing for easier comparisons between hypotheses' relative explanatory power. Every step in an argument must be logically sound; a single weak link can doom the entire chain. When the evidence is inconclusive, use Occam's Razor to discriminate between hypotheses. Pay attention to falsifiability. Science does not concern itself with unfalsifiable propositions.
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