Well, good for you. But why tell me that? Why not keep the dark secret of your double life -- a morally upright person who slums about reading rough trade like me -- to yourself? Why not manufacture some flattering lie, or if that is intolerable to you, some studied neutrality ("You're still writing, I see"), or better yet say nothing at all? Why go out of your way to mention both that you read the column and that you disagree with it?

Because it is important to him that I should know his opinions of it, and of me. The point of saying such a thing is this: I am not only open-minded enough to read your column. I am civil enough to tolerate your company, even to speak with you. But do not mistake that for a concession that we are somehow alike, or even equals. You should know where you stand, and mind your place.

Actually, what it really means is something else again. What it really means is: I am accustomed to dealing only with people who think as I do, to the point that I regard people who hold contrary views as a species of alien. If I read opinions with which I disagree, it is with the greatest of effort, exceeded only by the ordeal of conversing with their author.

Perhaps I'm making too much of this. But these kinds of remarks do not come out of nowhere. They reflect a deeply ingrained habit of mind: a habit of certainty.

I've met these people all my life. They can be found as often on the right as on the left, and though this habitual certainty manifests itself in different ways -- on the right, it tends to emerge as sneering contempt, on the left, as smug sanctimony -- what is common to both is the notion that a political philosophy is made up entirely of a set of nostrums, to be absorbed and repeated without further inquiry.

Usually these are said to one another. Occasionally they are bellowed across the no man's land dividing them from "the other side." But at no time does either side question its own beliefs, or attempt to understand how another person could have come to a different point of view, except out of either stupidity or malevolence. It is enough to establish to which tribe one belongs, and to which one does not; who the good guys are, and who the bad.

One offshoot of this is a tendency to classify political leaders in binomial terms: good, bad, on, off, one, zero. As in, "Jean Chretien is ruining the country." Or, "George Bush scares me." Such certainty, and such simplicity! Mr. Bush has his strengths and weaknesses, and his policies may or may not be to your taste, but to think of him as "scary" you have to inhabit a very dark world, full of hobgoblins and warlocks.

Mr. Chretien, likewise, has done well in some areas, poorly in others. He is in some ways admirable, in other ways loathsome. He is undeniably shrewd, yet often betrays a lack of judgment. How much more interesting it is to consider him in this light, as a flesh-and- blood human being, than as the simplistic caricature of so many newspaper columns.

To maintain such an us-and-them view of the world requires a constant effort at self- quarantine, else the purity of one's own opinions be contaminated by contact with others.

The most extreme example I have seen of this was the woman to whom I was introduced in a restaurant not long ago. Or at least, an attempt at an introduction was made. But before I had got within six feet of her she threw up her hands in front of her face, exclaiming, "No, no, this wasn't my idea! I don't agree with any of what you write." Which is fair enough, except she said it with a sort of flustered smile, even a laugh, as if she were letting me in on some private embarrassment. She expected I would understand: She couldn't possibly soil her hands with mine, let alone exchange a few words. It wasn't as if it was anything personal.

Still, at least she was upfront about it, without the attempt, at once both ingratiating and self-important, to pretend to an open-mindedness she did not possess.

"I read you -- though I can't say I agree with you." Perhaps every journalist hears this at one time or another. To which the critic Cyril Connolly advised there was only one possible response: "I know you -- though I can't say I like you."