That's important, Ed. It is terribly easy to assume we 'have the truth' so everyone who disagrees is wrong. To my mind that impoverishes the person who had the truth: people, by and large, are not stupid and so if they have a different view to you they probably have a good reason for thinking what they do. Understanding their view will not necessarily show you to be wrong - though it might - but it will almost certainly allow you to understand your own position better.