Appeals to authority are always deductively fallacious; even a legitimate authority speaking on his area of expertise may affirm a falsehood, so no testimony of

Appeals to authority are always deductively fallacious; even a legitimate authority speaking on his area of expertise may affirm a falsehood, so no testimony of any authority is guaranteed to be true. source: http://www.logicalfallacies.info/relevance/appeals/appeal-to-authority/ http://www.logicalfallacies.info/relevance/appeals/appeal-to...