A lot of my friends at school have started smoking. It seems really cool. Do you think that I should give it a try?
If it was easy to quit smoking, then the decision to smoke would be what economists call a “costlessly reversible investment”. You would be well advised to follow your instincts that the cool, sexy image and the nicotine buzz are attractive enough to outweigh the financial costs plus the aging skin, bad breath, wheezing, stained teeth, and the likelihood of cancer or heart disease. There would be no harm in giving smoking a try because you would continue to learn more about both its costs and its benefits. If at some future stage you decided you had made a mistake, you could simply stop.
In reality, it is not easy to quit. The decision to start smoking is therefore not costlessly reversible. In an uncertain world it is usually worth waiting to find out more before making decisions which are hard to reverse. Even if a primitive cost-benefit analysis recommended smoking, a more sophisticated view would recognise that plunging in too quickly has a hidden cost: you lose the opportunity to wait and find out more. Admittedly, if the benefits of smoking seem very large and the costs of smoking seem very small, even the hidden cost of starting young would not be enough to discourage you.
Still, the fact that few 35-year-olds suddenly decide it’s time they started smoking suggests that there is some value in waiting for a few years to gain a new perspective. I should mention that if you confidently expect to die tomorrow, the value of waiting to learn more is zero and you should puff away. The tradition of the last cigarette for the condemned man is therefore perfectly rational.
First published at ft.com.