Make a bandwagon appeal. Four out of five dentists prefer Brand X gum for their patients who chew gum. What makes that a bad argument? Maybe a lot of things. How many dentists were surveyed? How were they selected? How many of them had expertise relevant to the topic at hand? There are many ways to manipulate this kind of argument, so it should always be treated with skepticism. Still, even if a well-selected sample of relevant experts was found, this is not a scientific argument. It doesn’t matter how many physicists believed in lumeniferous aether or phlogiston or a bunch of other things hundreds of years ago. Their belief made nothing true, and the belief of scientists today makes nothing true. What matters scientifically is the evidence that proves or disproves theory. But what sways your audience? Will they fall for this kind of appeal? In ‘fact’, nine out of ten non-scientists will fall for bandwagon appeals. Just don’t ask me where I got that statistic.