Atul Gawande

There are, in human affairs, two kinds of problems: those which are amenable to a technical solution and those which are not. Universal health-care coverage belongs to the first category: you can pick one of several possible solutions, pass a bill, and (allowing for some tinkering around the edges) it will happen.

You want to ensure people can do it right 99 percent of time. When we have to fire one of our surgical trainees, it is never because they don't have the physical skills but because they don't have the moral skills - to practise and admit failure.

Between 1939 and 1945 you produced weapons and war equipment valued at thirteen billion dollars, 70 per cent of which you shipped to your allies. The same process is going on today in Canada's much larger and growing industry.

Supplying fuel for a Mars expedition from the lunar surface is often suggested, but it's hard to make it pay off - Moon bases are expensive, and just buying more rockets to launch fuel from Earth is relatively cheap.