But no matter how intensely we desire certainty, we should understand that whether because of our limits or randomness or future unknowable confluences of events, something will inevitably come, unbidden, through that door. Some of it will be uplifting and inspiring, and some of it will be disastrous.

Much the same will be true for the issues that I cover in this book. I’m not saying that we should be confident that value lock-in or major catastrophe will occur this century. What I am saying is that their chance of occurring is very real—certainly more than 1 percent, and certainly greater than many everyday risks, like dying in a car crash. When combined with how much is at stake, the expected value of trying to ensure a good future is enormous. When we’re applying the significance, persistence, and contingency framework, we should therefore be thinking about expected significance, expected persistence, and expected contingency.

We deal with complex systems whose structure we can understand only imperfectly. The problems we face are rarely completely specified, and the environment in which we tackle them contains irresolvable uncertainties.

Most of what will be important in the future is outside our knowledge; it exists only in the future. The direct approach demands a capacity for prediction that we can never possess.

Real businesspeople operate in ‘large worlds’, in which problems are ill defined and there are no objectively correct answers. Moreover, the ‘right’ answer will often not be apparent, even in retrospect. Effective decision-makers in large worlds are not maximising; they do not have and never can have the information needed to make the relevant calculations. They confront radical uncertainty. Often they not only do not know what will happen but do not even know the kinds of things that might happen. Although we must abandon ‘the pretence of knowledge’, individuals, institutions and businesspeople need to act in the face of uncertainties.