How should we deal with denialists? (Image: Francis Miller / Contributor)

ENGAGING with people who doubt well-established theories is a perennial challenge. How should we respond?

My answer is this: let them be heard. Examine their evidence. Consider their interpretation. If they have anything of substance to say, then the truth will out.

What do you do, however, with people who, after their claim has been fully discussed and thoroughly debunked, continue to make the claim anyway? This, of course, is where scepticism morphs into denialism. Does there come a point when it is time to move on to other …