THE most entertaining part of the post-budget coverage has been watching the Liberals try to decide whether the budget's spending cuts were or were not a repudiation of something called Liberalism.

At one extreme, you had Warren Allmand inviting most of the rest of the party to leave. ("I'm being consistent with Liberalism. I'm a Liberal, and those who are not supporting those policies . . . they should be considering what they should do.") For his part, the Prime Minister bit his lip and allowed how much it hurt to take such measures. "It's not out of pleasure, sir," he reproached a hectoring Peter Gzowski. "I'm not a doctrinaire right-winger. I'm a Liberal, and I feel like a Liberal, and it's painful." Hath not a Grit feelings? Hath not a Grit principles?

But wait a minute: Isn't that supposed to be the whole point of Liberalism? Not having any principles? As Jean Chretien says in his book, "That is one of the great things about being a Liberal; you can base your decisions on the circumstances, without having to worry about your established public image." In other words, a Liberal does whatever works, or whatever the situation demands, or whatever will get him elected, but never for any reason that could be identified as a political philosophy. It's what Paul Martin recently called "the definition of a Liberal." The lack of one, I mean.

So when Mr. Allmand says he is being consistent with Liberalism, he is being inconsistent with Liberalism. This is overstated, of course. The Liberals haven't changed all that much. They didn't cut spending until the very last minute they could possibly get away with it. It wasn't until the disaster, the Towering-Inferno, Love-Canal catastrophe of a $12-billion increase in debt interest costs - a 32-per- cent rise in two years - that they finally acted. In such circumstances, reducing program spending by 8 per cent is not a "swing to the right." It's a certificate of sanity.

And Liberals in the past have not been averse to a little politics. The National Energy Program was not exactly an exercise in pragmatic tinkering. But never mind. What is significant is that the Liberals would like to be known for their lack of any guiding ideals. This is the most persistent strain in Canadian politics: the aversion to ideology. Our politicians will cross the street rather than risk being called principled. Indeed, the absence of conviction is held up as a feature that distinguishes our politics from theirs, and is therefore self-evidently good. Our national ideology, then, is that we have no ideology, and a rigidly enforced ideology it is, too. There is no dogma like pragma.

At times, this borders on the pathetic. An example is Mr. Martin's repeated insistence that the difference between the Liberal and Tory approaches to the deficit was that for the Liberals deficit reduction was only a means to an end, whereas for the Tories it was "an end in itself." The statement, of course, is meaningless. Nothing is an end "in itself." Whatever we desire, it is desirable because of something: some benefit it yields, some sensation it offers.

Press ever so slightly, and most of what is said in the name of "pragmatism" turns to mush. No one can encounter the world entirely without an organizing perspective. If it means "not wedded to one set of principles," on what principle are the old principles to be abandoned? If it means "doing whatever works," how is what "works" to be recognized, without some principle to define it?

When someone says, "That's all right in theory but not in practice," they are breaking so much wind. If it's not all right in practice, it's not all right in theory. The only good theory is one that works in practice. What they really mean, most of the time, is this: I don't have a good argument against the theory, so I will appeal instead to the crude prejudice called "common sense."

There's a logical falsehood known as "arguing from authority": asking your listener to believe a thing not by virtue of the quality of the argument, but by the exalted position of the arguer. Expansive appeals to "common sense" are a kind of argument from lack of authority: A thing is so not because anyone in particular says so, but because everybody says so, or at any rate everybody who knows nothing about it.

Will Rogers said it best: "There's lots of things everybody knows that just ain't so." Including the one about the Liberals breaking with Liberalism.