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(∃R:e∉R)⇏(∄R:e∈R)
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(Sorry, I usually try not to tweet about contemporary politics.) Related: Failure to reject H₀ as rejection of H₁, Type II error, argument from ignorance (“likely coined by philosopher John Locke”!), autoepistemic logic. en.m.wikipedia.org/wiki/Argument_from_ignorance