As far as I know it was Aristotle who made the distinction between Dialectic and Rhetoric. For that matter, he discovered the laws of logic, which makes him one of the indispensible people in history.
Dialectic is the rational discussion between two or more people based on the available evidence. Rhetoric is based on emotion and logical fallacies. (Strictly speaking, it’s based on childish, indeed infantile, emotion.)
My experience has been the easiest way to distinguish dialectic from rhetoric is that those who use rhetoric impulsively blurt out answers without thinking (sometimes they even make things up on the spot). Although, in their minds, they believe their answer is rational and based on the facts. It’s not.
Example: when the wars in Afghanistan and Iraq were started, I would hear from the Young-Republican-I-Support-the-Military-But-Will-Never-Join types about “If we don’t fight them over there we’ll have to fight them here.” (Notice these chickenhawks always say “we,” not “I.” What they really mean is “you,” not “me.”).
Their answer is pure rhetoric – pure dissembling rhetoric. When I pointed out that Iraq had an economy one percent of the U.S.’s, that the CIA had helped put Saddam Hussein in power, that he was our ally for decades and we armed him in the war against Iran, that he had no army, navy or air-force worth anything compared to us, and there is a picture of Donald Rumsfeld shaking hands with his buddy Hussein…they knew none of these things. The only thing they “knew” was that Hussein suddenly decided to attack the U.S.
Why did Hussein suddenly decide to attack a county 100 times stronger than his? Well, just because. No, not really. It’s because he had a conniption fit and immediately turned into an Insane Evil Homicidal Maniac Who Was of Course the Reincarnation of Hitler. At least that’s what the government told us. Government propaganda, that is.
Without exception governments always use the most simplistic of propaganda techniques to paint foreign leaders they want to go to war against as Compleatly Insane, who will in their rabid mad-dog-drooling lunacy attack the strongest country ever, thinking, somehow, they can win. As George Orwell put it, “Every war when it comes, or before it comes, is represented not as a war but as an act of self-defense against a homicidal maniac.”
The retarded always fall for this propaganda. As Joseph Goebbels, Nazi Minister of Propaganda, said, “…it's the leaders of the country who determine the policy, and it's always a simple matter to drag the people along whether it's a democracy, a fascist dictatorship, or a parliament, or a communist dictatorship. Voice or no voice, the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked, and denounce the pacifists for lack of patriotism, and exposing the country to greater danger."
People engaged in a dialectical discussion can be recognized because they are thoughtful people. People who use rhetoric are never thoughtful – they’re always impulsive. Although, again, they think they are rational and thoughtful.
Impulsivity, except in certain select instances, is not a good thing. Impulsivity and stupidity together puts individuals in prison (the average IQ of prisoners’ is 93). For groups, impulsivity, coupled rhetoric and propaganda, leads to meaningless wars that can destroy the country (Germany and Japan found out about that the hard way).
Fortunately, it is easy to demolish the arguments of those under the spell of rhetoric and propaganda. They never have any proof. Unfortunately, they rarely change their minds. They don’t believe the evidence, since the cognitive dissonance makes their brains hurt. Stupidity can’t be fixed; ignorance, sometimes.
It is a very bad thing that so many people fall for emotion-based rhetoric and propaganda. They never know it, though. After all, Aristotle also pointed out there are two kinds of ignorance: one in which you know you are ignorant, and the double-ignorance in which you are ignorant and don’t know it.