How do scientists decide they have discovered something? Gravity's Ghost is a detective story about a potential discovery called 'the Equinox Event'. At the same time, it's an investigation of the nature of science.
For nearly half-a-century scientists have been trying to find the elusive gravitational waves. Nowadays they are searching with devices costing hundreds of millions of dollars - huge interferometers with arms 2.5 miles long. I am a sociologist who has been studying these physicists since the early 1970s; since the mid-1990s I have spent much of my time hanging out with them. I even managed to pass as a gravitational wave physicist, Nature reporting in July 2006, 'Sociologist Fools Physics Judges'.
For 18 months at the end of the 2000s the physicists thought they might, at last, have found a wave. I went to every one of their meetings as they argued and debated about what they had seen, talking to them in corridors, bars and restaurants. Based on the trust I had built up over the years, I recorded the talk and took photographs. There was a twist - it could be that the signal they were analysing wasn't anything real, not even noise; it could have been a fake signal inserted into the devices to test their abilities. What was the Equinox Event - that fleeting something picked up by the Laser Interferometer Gravitational-Wave Observatory (LIGO) on the night of 2007's September Equinox? The argument went backwards and forwards, different parties staking-out different positions, analysts desperately refining their signal processing 'pipelines', philosophical arguments breaking out over the very nature of statistical analysis, over whether one event could ever count as a discovery, over what was meant by a 'publishable' result.
"...for a sociologist there are always two interwoven stories even if one of them plays only a minor part on the page. There is the gripping tale of the Equinox Event as a potential discovery in physics... There is also a story about how our society makes knowledge and the place of science at the heart of the process..."
Of course, for a sociologist there are always two interwoven stories even if one of them plays only a minor part on the page. There is the gripping tale of the Equinox Event as a potential discovery in physics with, like all good detective stories, a totally unanticipated twist at the end. Though no technical issues are dodged, the writing is, I believe, clear enough to draw any educated reader into the to and fro of this physics debate and I worked with the publishers so that the surprise comes nicely at the turn of a page. There is also a story about how our society makes knowledge and the place of science at the heart of the process.
Science no longer has the unquestioned authority it had when it was winning wars and promising power too cheap to meter. In America's political circles it has become possible to speak out loud of science being no more than one opinion amongst many. This extraordinary reverse in science's political fortunes has sometimes been blamed on the academic movement known as post-modernism. In a way Gravity's Ghost is part of the post-modernist movement. I was writing papers in the early 1970s, and books in the 1980s, about the difficulty of producing decisive proofs that would settle scientific controversies. Among my topics were early disputes concerning the detection of gravitational waves; I summarise them in Gravity's Ghost and bring out the impact of their memory on the debate about the Equinox Event. Unknowingly, when I was writing in the 70s and 80s I was helping to develop a position that now provides comfort for the anti-science side in the contemporary debates about creationism and climate change. This is madness, and yet we cannot pretend that the close studies of science that took place in the 1970s and onward did not happen. Science is not what people thought it was early in the Twentieth Century and it is no good pretending that it is perfect. We have to find a way to choose science even while acknowledging its imperfections.
"Science no longer has the unquestioned authority it had when it was winning wars and promising power too cheap to meter. In America's political circles it has become possible to speak out loud of science being no more than one opinion amongst many..."
In other books I have argued that the solution is to treat science, not as a quasi-logical road to truth but as a display of expertise. A sane society will choose to give more weight to the views of those who know what they are talking about because they have long experience in applying their skills in the relevant specialist domains. Gravity's Ghost is a display of scientists using their skills and expertises. In the book you will see science beset with uncertainties and making the mistakes that characterise all pioneering scientific work but the question is, who could do this work better? You will see how scientists make judgments about things of which they cannot be certain. One way to defend science is to see it done and marvel at the virtuosity of its practitioners even as they struggle. Science does not touch the divine but it is still the best way to distil human experience of an uncertain world.
"A sane society will choose to give more weight to the views of those who know what they are talking about because they have long experience in applying their skills in the relevant specialist domains. Gravity's Ghost is a display of scientists using their skills and expertises..."
In a final chapter, called the 'Envoi', I try to develop this point into a political philosophy that I call 'elective modernism'. The enemies of elective modernism include scientists themselves wherever they make unjustified claims for what they can achieve. The values of science should lead not follow. Too often scientific heroes and their incomprehensible texts assume the iconography of religion to gain a popular audience; too often science is justified as hard-nosed capitalism; too often science is said to be able to exhaust all cultural domains. Science is not religion, nor capitalism, nor a universal panacea: science is virtuoso expertise applied to specialist domains. Accept this and its values can form the basis of a good society, a role for science which is, perhaps, still more important than its products.
Gravity's Ghost is a description of 18-months of gripping scientific detective work with all its skill, passion, joy and sorrow. It does not show gods in human form, it show what happens when humans do their best in the face of the hardest kind of problem. Though the book is written to be read as a detective story, I hope its importance will be wider: to exemplify how our difficult decisions should be made even when we cannot be sure we are making them right.