The Art of Uncertainty Quotes

“I returned and saw under the sun, that the race is not to the swift, nor the battle to the strong, nor bread to the wise, nor riches to men of understanding, nor favour to men of skill; but time and chance happen to them all.

[Quoting Ecclesiastes 9:11 in the epigraph to the Introduction.]”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Probabilities can, and should, change rapidly as new information arises.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“The addition, or the OR rule: add probabilities of mutually exclusive events (meaning they cannot both happen at the same time) to get the total probability. For example, the probability of Juliet winning is ¾, since it can occur through ‘a tail at the fourth throw’ with probability ½, OR a ‘head + tail’ with a probability of ¼. 4.​The multiplication, or the AND rule: multiply probabilities to get the overall probability of a sequence of independent events (meaning one does not affect the other) occurring. For example, the probability of a head AND a head is ½ × ½ = ¼.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“We now know that bin Laden was in the compound, and was killed, presumably vindicating those who had given a high probability to his presence there. Some have argued that the wide diversity of views among the intelligence advisers should have been condensed into a single probability assessment before being presented to Obama13 but, personally, I feel a decision-maker should know when his advisers disagree – Obama needed to synthesize what he was hearing and take ultimate responsibility.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“We have seen how uncertainty is best thought of as a relationship expressing ‘your’ ignorance about something tangible. But ignorance is not all or nothing, and when we use expressions such as ‘likely’ and ‘almost certain’ in our daily language, we are essentially communicating degrees of uncertainty, and a natural next step is to be more precise and put our uncertainty on a numerical scale.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Broadly, we can have aleatory uncertainty about the future, which we cannot know, or epistemic uncertainty about the present or past, which we do not know.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“However, the basic lesson still holds – our concern tends to be not so much related to the uncertainty about whether something will happen, as uncertainty about what it will be like if it does.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“hazard is more ‘dread’ if it is uncontrollable, involuntary, fatal, inequitable and increases risk to future generations – think nuclear accidents. A potential threat is more ‘unknown’ if it is unobservable, novel, and ill-understood – think attitudes to electromagnetic radiation from mobile-phone masts. Familiar activities like cycling, while potentially risky, are neither unknown nor dread.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“This book is primarily concerned with an analytic approach to risk and uncertainty, using numbers, statistical models, and so on, but it’s the feelings about risk that tend to dominate our personal attitudes to the perils we may face.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Sometimes we just prefer not to know.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“When around 1,000 adults in Germany7 were asked, ‘Would you want to know today when you will die?’, 88% said no (8% were uncertain, and only 4% said yes).”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“The crucial issue reflected in these definitions is that (with possible subatomic exceptions, as we shall come to in Chapter 3) we shall not be thinking of uncertainty as a property of the world but of our relationship with the world. This means that two individuals or groups can, quite reasonably, have different degrees of uncertainty about exactly the same thing, due to them having different knowledge or perspectives, as we found with the spun coin.† This vital idea will run through the whole book.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“This is reflected in a more formal definition,2 which I personally find appealing: Uncertainty: the conscious awareness of ignorance.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“where the uncertainty is due to what we might call chance, or unavoidable unpredictability; this is sometimes termed aleatory uncertainty, about the future we cannot know. But now the object is the current state of the coin, and the uncertainty is due to your lack of knowledge; this is called epistemic uncertainty, about what we currently do not know.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“I then flip the coin, catch it, but cover it up before you see it, although I take a quick peek. I then ask, what’s your probability it’s heads? Things have changed, as the event is now decided – there is no randomness left, just ignorance. Not only that, but I know the answer and you don’t, which is a situation that some can find unnerving. Most people are now hesitant to give an answer but may eventually repeat ‘half’ or similar, although somewhat grudgingly.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Rumsfeld did leave out one combination – the unknown knowns, which philosopher Slavoj Žižek described as ‘things we don’t know that we know, all the unconscious beliefs and prejudices that determine how we perceive reality and intervene in it’.5 More generously, this category may include accurate understanding that we do not know we have – so-called tacit knowledge.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“This may require facing up to deep uncertainty – limitations of our whole conceptualization of the world, reflecting the boundaries of our ideas as to what could happen. This requires admitting both the gaps in our understanding and the limits to our imagination, and rather than doing yet more complex analysis and trying to produce an optimal course of action, it may be better to seek flexible strategies that should be resilient to most eventualities.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don’t know we don’t know. —United States Secretary of Defense Donald Rumsfeld in 2002”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Once we accept a personal, subjective view of probability and uncertainty, we are led naturally to Bayesian analysis, in which we use the theory of probability to revise our beliefs in the light of new evidence. These ideas were crucial to Alan Turing’s codebreaking in the Second World War and now help us to interpret imperfect data, such as automated recognition of faces in crowds. We might even have Bayesian brains.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“this book is about trying to think slowly about our ‘not-knowing’.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“1.​what we know (knowledge); 2.​what we don’t know (uncertainty); 3.​what we are doing to find out (plans); 4.​what people can do in the meantime to be on the safe side (self-efficacy); 5.​and that advice will change (flexibility and provisionality).”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Put simply, it’s that uncertainty is a relationship between someone (perhaps ‘you’) and the outside world, so it depends on the subjective perspective and knowledge of the observer.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“Twenty-one per cent of millennials (born 1981–96) say they’ve changed jobs within the past year, more than three times the rate for non-millennials.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“This constant state of uncertainty is an essential part of the human condition.”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck

“I returned and saw under the sun, that the race is not to the swift, nor the battle to the strong, nor bread to the wise, nor riches to men of understanding, nor favour to men of skill; but time and chance happen to them all.’ —Ecclesiastes 9:11,”
― David Spiegelhalter, The Art of Uncertainty: How to Navigate Chance, Ignorance, Risk and Luck