"Aristotle could have avoided the mistake of thinking that women have fewer teeth than men, by the simple device of asking Mrs. Aristotle to keep her mouth open while he counted"

This quote by Bertrand Russell is an amusing method of explaining the value of empirical proof. Aristotle, a distinguished philosopher, made the error of assuming that females have less teeth than males with no proof to back it up. Russell is suggesting that Aristotle could have prevented this mistake by just asking his other half to open her mouth and counting her teeth. This would have supplied him with the empirical proof he required to show or negate his hypothesis. Russell's quote is a reminder that we need to constantly make every effort to back up our claims with evidence, rather than relying on assumptions. It likewise functions as a tip that we should always be open to new ideas and want to challenge our own beliefs.