Aristotle identified three elements in the art of rhetoric: ethos (authority or evidence); pathos (the emotional hook, one might say); and logos (a logical argument). His point was that to win over an audience required more than the facts. How these are marshalled and how they resonate matters, as Nobel Laureate, Peter Doherty, explains in his latest book The Knowledge Wars, which I reviewed in The Weekend Australian. The art is to make sure that pathos (and, in this day and age, the pithy media statement or resort to celebrity rather than expertise) does not undermine the ethos and the logos.