Till recently I used to think that smoking is by far the most irrational of all human habits. Why do millions of otherwise rational and intelligent people ignore overwhelming scientific evidence that smoking is injurious to health (causes lung cancer, makes you impotent, kills you…) keep puffing away nevertheless? My theory is that on the human timescale, the pernicious affects of smoking are far too remote to worry about before you actually get seriously ill, by which time it is too late. In other words, we humans cannot fathom a disaster till it is looming large in front of us. One can also say that smoking is simply a tough habit to kick, once you do get addicted (As Mark Twain claimed, “Giving up smoking is easy... I have done it hundreds of times”). I can say this from personal experience, having smoked off and on for several years before finally going cold turkey a couple of years ago.