Thanks to the example of Joseph Goebbels, we know that the Big Lie is a thing of evil.
But what about the rest of the items in the propaganda toolkit? Are they all evil too? Don't think so. Everyone has the right to argue for their cause. The question is, how far can you go?
Take the Big Promise. What's not to admire about someone who can make a gob-smacking promise and then deliver on it? Ted Turner promised the UN a billion dollars, and as far as I know, he made good on the deal.
The thing is, though, a Big Promise generally earns that description by promising the scarcely possible. Which brings us to this week's Big Promise by Sir William Gates, epoch-making entrepreneur, towering public figure and chronic emitter of vaporware.
Under which category should you file his promise of a Spam-Free World in Two Years? I'm inclined to put it in the Scarcely Possible and Most Likely Just Talk category. Aardvark has a clear-eyed assessment of Gate's proposals here. What I'm interested in is the thinking behind the promise.
Public figures feel driven to make Big Promises in a way the rest of us never do. They worry about things that bother us less: maintaining profile; out-doing the competition; feeding the ego; waxing the legacy; feeding the ratings; or maybe just pumping a little life into your polling. Also: if they're not preoccupied with those things, there's usually a clutch of handlers who will be.
I got my first experience of this when I was working in the Prime Minister's office. If you were watching the polling for the fourth Labour government - rocketed spectacularly through 1984 to 1987, melted down around 1988, flat-lined soon after - you'll recall that by 1990, things were looking pretty dire.
The economy was tanking. Unemployment was getting to numbers that people hadn't seen in more than a couple of generations.
On the 9th floor of the Beehive, where hope springs eternal, we remained faintly optimistic in the face of dispiriting evidence to the contrary. Even so, we had our doubts when we had a visit one day from some highly-regarded PR people who'd come down from Auckland to show us a way out of the woods.
"You've got to do something bold," they said.
"It's got to have real impact," they said.
"Here's what you do," they said. "You go out and you promise to halve unemployment in three years."
I remember some blinking, I remember some raised eyebrows, I remember the odd sharp intake of breath. I don't remember anyone pounding the table and saying "Brilliant, mate!" There might have been some coughing.
It should have died there but, well, the thing survived. And like that little skinny creature with the freaky head in Alien, it was soon screaming around the building and colonising the apparatus of government. It was only a matter of time before it got to the Prime Minister.
Geoffrey Palmer is one of the smartest people I've ever met. He knew it was drawing a long bow to make a promise like this, and he knew that several dozen economic indicators would have to do a quick U-Turn to make the Big Promise a reality, but he also knew what the Cabinet and the Caucus and the polls and the Press Gallery were saying: We Had To Do Something.
Thus is the most frail kind of Big Promise born: the act of desperation.
You have to kid yourself into this kind of thing: it's worth a try, might as well give it a shot, you never know, nothing to lose. This thinking comes to you readily if you've been a follower of horses. How everyone else talked themselves into it, I'm not sure.
So imagine my surprise when the Big Promise turned out to be a great big hit. The polls turned around right away, unemployment was down to 1% within a year, and the election that November was a landslide for the Labour Government. I stayed on for a few more years, then left to set up Amazon.com. Would you like a Tui?
Conclusion, then: people will see through the Big Promise if it's really an act of desperation.
As far as Big Promises go, they don't get much bigger than the one JFK made: a man on the moon by the end of the decade. In its own way, it was a kind of desperate act: he was worrying about being outflanked in the cold war. But it didn't play that way. It didn't have desperation written all over it; it looked and sounded inspired, and it galvanized people. It captured their imagination.
Inevitably, Dubya's people tried out a spacesuit on their guy last month, and then appeared to forget about it in the State of the Union speech, presumably because it didn't focus-group well. It probably only just counts as a Big Promise, anyway, because it expressed its measurable goals with almost lawyerly caution, relating them mainly to going back to the Moon. In other words: No pain, no gain.
So. Does the Gates one match any of these categories of Big Promise?
Well, it's hardly an act of desperation.
It sets a clear, measurable goal - spam-free in two years - so it fits the pain/gain requirement.
In its way, it's even quite inspiring and it could well galvanise people. Promise a spam-free world and you will capture their imagination.
But here's the cute thing about this guy. As usual, he's promising to make it happen, but you know that when it does, it's more likely to be achieved by some smart people who don't work anywhere near Redmond. By doing this, he's getting talk focused on achieving a king-hit against spam, and he's promising a lot of muscle, for which we may turn out to be grateful. And, of course, he's dressing himself in the clothes of the good guy. I just have the feeling that the solution, when we get it, will come from somewhere else.
I'll be glad to be proven wrong, though, and I'm going to put my money where my mouth is. Mr Gates, if you can rid the world of spam within two years, I will go back to using Outlook as my mail client. Promise.