I've spent a lot of my life arguing that the hard-headed "rational" analysis so beloved of economists needs to be tempered by human emotion. But it also works the other way: sometimes we need to curb our emotional reactions and force ourselves to think coolly about what we really want and the most sensible ways to go about getting it.
I think this every time we're faced with another terrible act of terrorism. The first emotions are shock and horror, soon followed by a desire to hit back, to find a government to blame and demand action from. Promise us this will never be allowed to happen again.
Such reactions are only human, but when we surrender to them, we leave ourselves open to manipulation by the unscrupulous – and I don't just mean the terrorists.
But that's a good place to start. Terrorism is practised by the weak to get under the guard of strong. Their goal is not so much to terrify us and weaken our resolve as to provoke us into doing something stupid; something that damages us and benefits them.
Vengeance, retaliation, belligerence – these are common emotions at times like this, particularly among men. The great temptation at present is to send all our military might to the Middle East and defeat these forces of evil once and for all.
But how many times have we tried that without it working?
It's not easy to defeat your opponent so completely that no problem remains. It's much easier to make a strike that doesn't fix anything and actually makes things worse.
It never crosses the mind of the bellicose among us that the other side may be hoping to provoke us into hitting back. Why? To make them into martyrs, to show it's Muslims against the world, and to win them support from young potential fighters or terrorists in our midst.
Even the heroes who indulge themselves by shouting at women wearing headscarves are helping the side they hate.
It's arguable that, in its desire to punish someone after the terrorist strikes of September 11, 2001, the US has made things worse for itself and the rest of us. It's doubtful how much lasting benefit will result from all the lives lost and money spent in Afghanistan.
And the decision to invade and occupy Iraq has achieved little, but has destabilised long-standing enmities in the Middle East, greatly increased hatred of the US and, as the rise of Islamic State demonstrates, created a quagmire from which the Americans can't extract themselves.
No one's allowed to say it, but it's obvious: every time Australia muscles its puny way into these problems on the other side of the world – as if the Americans and Europeans need our help – we increase the risk of terrorism Down Under.
It's funny that the people who worry most about the "unsustainable" growth in government spending, tend to worry least about ever-increasing spending on defence, policing, security and surveillance.
Years of contact with economists has made me hyper-conscious of people using the media to push their vested interests. Almost all the alleged terrorism experts broadcast by a wide-eyed media at times like these seem to have a single message: do more, spend more. Oh, the risks we face.
All the understandable attention the media devote to terrorist attacks, anywhere in the world, can't help but leave us with an exaggerated impression of the risk of such an attack happening here.
A few years ago, Mark Stewart, a professor of civil engineering at my own University of Newcastle, estimated that the risk of an Australian being killed in a terrorist attack is one in 7 million each year, which is about the same as the risk of being struck by lightning.
It's not possible for our politicians to guarantee nothing bad will ever happen to us. But it is possible for them to cover their backsides by spending lots of money, progressively diminishing our freedoms in the name of protecting them, and putting on a show at airports.
A timely article in this week's issue of The Economist says that "a lot of what passes for security at airports is more theatrical than real".
Despite the likelihood that the recent Russian plane crash over the Sinai desert was caused by a bomb in the hold, attempts to blow up airliners are quite rare, it says. And the enhanced airport security introduced after 2001 has played no role in thwarting any attacks.
The ban on carrying liquids on board was introduced in 2006 after a plot to bring down several planes crossing the Atlantic was foiled thanks to a tip-off. In the time since then, nobody has been caught trying to get liquids on board to combine into a bomb.
Nor have any would-be bombers been intercepted since the requirement for passengers to remove their shoes was brought in, after a shoe bomber trying to set off an explosion was subdued by passengers.
The US Transportation Security Administration has a budget of more than $US7 billion ($10 billion) a year, but this year government inspectors succeeded in getting fake bombs and weapons through the screening process in 67 out of 70 tests in airports across the US.
So maybe no passengers have been caught doing the wrong thing because the security is such an effective deterrent, or maybe it's largely a showy waste of our time and money.
