The plan with three brains

This month Daniel Kahneman turned 80. Long revered among experts in the decision sciences, his work reached much wider public attention with the publication of the bestseller Thinking Fast and Slow.The central tenet of the book, what he calls a ‘useful fiction’, is that we obviously have more than one way of thinking. The ‘fast’ way — imagine answering ‘What is two plus two?’ — is unconscious, effortless, decisive and fast. The second — ‘What is 17 times 34?’ — is conscious, effortful, dithery and slow.

There’s nothing new about mental dualism, of course. But what is useful about Kahneman’s simple model is that he names them neutrally ‘System One’ and ‘System Two’ and acknowledges we need both. There are fervent debates about the relative strengths of instinct and reason, so let’s just say it is best to leave emergency braking to System One; if you are designing a suspension bridge, on the other hand, you might want to get System Two involved. Both systems are capable of error: the knack lies in using both.

I think this metaphor now needs to be extended one stage further. For, in the past 30 years, the huge explosion in computer processing power has effectively created a kind of ‘System Three’. A third kind of decision-making apparatus with its own distinct strengths and weaknesses. Here again the task ahead will involve deciding what this new power can do better than us — and where it shouldn’t be used at all. Equally important will be the task of working out ways to use the power of ‘System Three’ in tandem with Systems One and Two.

What do I mean here? Well, it is widely believed the triumph of Deep Blue over Garry Kasparov in 1997 marked the final victory of machine power in chess.