Humanists do not claim to know, we just ask you to be wary of those who claim to know. Who told them? What does their knowledge mean? Why should you trust them? Above all, don’t take my word either. Don’t take anybody’s word for it. Find out for yourselves.
– Stephen Fry, The Little Book of Humanism: Universal lessons on finding purpose, meaning and joy
And that applies generally, not just within humanism.