Here are a couple of highlights from the leaders’ debate last Tuesday evening: 

“That’s a good point, Christopher. Most economists do agree that selectively removing GST from fruit and vegetables is a dumb idea. We’d better rethink that one.”

“Well, Chris, you make a good point too. It looks as if the foreign-buyer tax won’t raise as much as we’d first thought.”

They didn’t say anything of the sort, of course.

Typically, political debate in modern democracies is akin to male walruses fighting over a patch of beach.  Abetted by the media, politics is more of a blood sport than a forum for well-reasoned debate.

It’s a far cry from the hopes of early democratic theorists. They thought that if we could harness the collective reasoning of entire populations, political leaders would make better decisions. During the 18th century Enlightenment, when democratic political ideas began to gain traction, reason was all the rage. 

Reason is indeed a fine thing. But unfortunately, it turns out that we’re not that good at it. Human beings have an array of built-in cognitive biases that tend to subvert clear thinking.

A sound argument is built from defined premises, using evidence and logic, to reach a valid conclusion. But people are actually more inclined to work backwards, cherry-picking evidence to support a preferred position. Nowhere is this more in evidence than in politics.

Noting our susceptibility to cognitive biases, French psychologist Hugo Mercier formulated the argumentative theory of reasoning. According to Mercier, humans developed the capacity to reason, not to do so individually, but so that we can argue with one another.

Mercier observed that people are easily convinced by their own arguments but are much more demanding when they evaluate the arguments of others. So, if we enter into an argumentative dialogue in good faith, we are much more likely to reach sound conclusions than if we reason alone.

For argumentative reasoning to work, the parties must engage with open minds. When people are just trying to win an argument, the error-correcting properties of argumentative reasoning don’t help them.

That brings us back to the leaders’ debate. There was certainly no shortage of argument, but it was not of the kind that produces sound conclusions. The good-faith element was just not there.

Democracy might have come of age in the Enlightenment, but human beings pretty much remain creatures of the Stone Age.