Over the past few years of teaching undergraduates I¡¯ve experienced a phenomenon that is new to me: different groups of students independently and indignantly questioning why they are being asked to ¡°guesstimate¡± things. Why, they ask, do we teach them how to do back-of-the-envelope calculations when limitless information is literally at their fingertips?

The answer to this question, in a much better form than I have managed in the past and from which I will draw heavily in the future, is provided in astronomer David Helfand¡¯s new book. The amount of information to which we have access has increased beyond imagining in the past decade. But how do we assess its value and correctness? More importantly, how do we identify and dismiss misinformation designed to fool us?

Helfand describes the process of science as a creative human enterprise that can provide us with a reason or mechanism for any event, and which doesn¡¯t require, or allow, a supernatural power. He offers a set of tools, from the power of the back-of-the-envelope calculation through the use of different types of graphs (and how to beware their manipulation), to the approximate estimation of probabilities, illustrating where ¡°common sense¡± can lead us astray. He also discusses the tricky link between correlation and causation.

These ¡°scientific habits¡± are then applied to the thorny topic of climate change, touching on a posteriori versus a priori calculations, the challenges associated with modelling complex systems, publication bias, and the uncertainty intrinsic to any scientific enterprise. But Helfand is careful to draw no conclusions for his audience (although his position is very clear). He wants a rational, dispassionate analysis of the issues rather than one driven by ideology and self-interest.

ÖйúAƬ

A Survival Guide to the Misinformation Age grew out of a series of lectures delivered to all first-year undergraduate students at Columbia University. With this in mind, the tone is in places a little unfortunate: kids these days, it seems to say, are innumerate, barely literate, gullible, suffering a ¡°nature deficit¡± and a lack of curiosity about the world around them. And this refers to students at Columbia: in the wider world, quantitative reasoning has, according to Helfand, all but vanished. I don¡¯t know if this is true of either students or the wider world, but I wonder whether such a tone will successfully bring doubters ¨C those most in need of these critical reasoning tools ¨C to Helfand¡¯s side.

Nonetheless, the scientific habits that he espouses are useful tools, and ones that we scientists take for granted. I suspect that this underlies my own lack of success when, taken by surprise, I struggled to convince my students of the benefit of ¡°guesstimates¡±; it is always difficult to articulate something that has become second nature (at least, that is my excuse). The fact that it is only recently that students have started asking me this question supports Helfand¡¯s idea that this is an emerging phenomenon, spawned of the information age. If true, then we all need to develop these scientific habits of mind so as to safely evaluate the enormous number of new ¡°facts¡± coming our way on a daily basis. This book is an excellent place to start.

ÖйúAƬ

Cait MacPhee is professor of biological physics, University of Edinburgh.

A Survival Guide to the Misinformation Age: Scientific Habits of Mind
By David Helfand
Columbia University Press, 344pp, ?19.95 and ?20.00
ISBN 9780231168724 and 1541022 (e-book)
Published 23 February 2016