Can a scientist win a Nobel prize by discovering nothing rather than something? That's how Albert Michelson won the Nobel Prize for Physics in 1907. His award was given for his development of interferometers, with which he measured the velocity of light with exquisite precision, hoping to find the ether. But he and Edward Morley found that the velocity of light is constant in all inertial frames, thereby eliminating the need for a luminiferous ether. Their failure to detect the ether stimulated Albert Einstein to produce the theories of relativity that opened up a universe with previously unimagined properties.
Ironically, when Michelson spoke in 1894 at the opening ceremony of the new physics laboratory at the University of Chicago, he asserted that the laws of physics were so firmly established that "future discoveries must be looked for in the sixth place of decimals". But within a decade, as the mysteries of the quantum world unfolded, this confidence yielded to profound ignorance about the fundamental laws of physics.
According to Stuart Firestein, ignorance - the known unknowns and even unknown unknowns - drives science. At Columbia, he teaches classes on ignorance, which he carefully defines as "the absence of fact, understanding, insight, or clarity about something". His thesis is that situations where no data exist, or where the data are deeply puzzling, become the stimulus to framing better questions. Science is unlikely to move forward if the thinking style of its practitioners is trapped in the comforting environment of facts that are generally accepted.
This is a short book, intended to be read in a couple of hours. Firestein's aim is to get us to think about knowledge in novel ways. To accomplish this, the first half of the book is an extended essay in six very short chapters. They are devoted to themes such as the exponential growth of data: the doubling time for scientific literature is only 10 years. The danger is knowing more and more about less and less. Another theme is the quality of data. We may be ignorant about uncertainty, or unpredictability, or even impossibility. Cosmologists such as Martin Rees are asking if the universe is deeply unknowable to the human brain.
The second half of the narrative looks at the four case histories of ignorance that Firestein showcases in his teaching. He begins in his own field, neuroscience, by discussing cognitive psychology, consciousness and the theory of mind, particularly mental activity in animals. What are horses or parrots or dolphins thinking? Are they self-aware?
For a second case study, we are asked to consider why theoretical physicists and astronomers feel so compelled to find a unified theory of everything. Vast knowledge exists about the operation of the quantum world and the fundamental properties of the universe. But we are ignorant about how to connect these two branches of physics. And the absence of a single theory that welds physics together leads to ignorance at the fundamental level. What is the mysterious dark matter and dark energy filling the universe? Why does mass have mass? Why is there structure, such as galaxies, in the universe? Our cosmic ignorance is profound.
For a third example, Firestein considers the brain. Why do we have one? How does it work? And the final case study is autobiographical. The author examines how his own thinking styles developed his career.
Anyone who is doing research in science, particularly those entering fields awash with data, should read this book. It is a witty and accessible guide to real science, and it is strong on the philosophy of scientific enquiry, without being intimidating. This is a splendid contribution to the public awareness of science.
Ignorance: How it Drives Science
By Stuart Firestein. Oxford University Press. 256pp, £14.99. ISBN 9780199828074. Published 19 July 2012