Gone, but Not Forgotten the Method of Science

THESIS Gone, but not forgotten Received wisdom holds that the one direction, and so violate this physics such as an inverse-square-law notion of an ‘aether’ — a medium principle; hence, an aether with a force acting between spins. pervading all space, and the material definite velocity cannot be consistent Other physicists have invoked ‘substance’ of the vacuum, if you with relativity. But quantum theory, an aether in trying to make sense of will — was permanently relegated Dirac argued, alters considerations the ‘spooky’ action-at-a-distance to the history books by Einstein’s of symmetry in an important way. apparently involved in quantum 1905 special theory of relativity, A hydrogen atom, for example, theory. In the spirit of playful which showed it to be unnecessary, can be in a spherically symmetric speculation, for example, physicist if not logically contradictory. But it state, even though, considered Nicolas Gisin of the University of seems, as it does so often in science, in classical terms, a system of an The laws of Geneva has explored what Bell-type that the situation isn’t quite as electron orbiting a proton never experiments, measuring correlations clear cut as that. Even Einstein had could. Perhaps, he suggested, physics haven’t between pairs of entangled particles, second thoughts on the matter. the vacuum could be similarly ruled out an might imply about the velocity of “I thought in 1905”, he wrote in a uncertain, spread over many quantum information. Given current paper in 1920, “that in physics one velocities in a symmetric way, aether with experiments, he suggests, the should not speak of the aether at all. and so not violate the principle certainty. velocity of such information would This judgement was too radical...”. of relativity. have to be greater than the speed of In 1951, writing in Nature, Dirac’s thinking on this point light, which can only make sense if Paul Dirac argued that the concept hasn’t restored the aether to there is a preferred frame, defined of the aether had been dismissed mainstream physics, but it may perhaps by the relative motions prematurely. “If one re-examines the have helped weaken the barrier of the particles involved. No question in the light of present against the exploration of such experiment, of course, has yet day knowledge”, he wrote, “one ideas, which persists today. Some detected evidence for such a frame. finds that the aether is no longer extensions of general relativity, What do we learn from this? ruled out by relativity, and good for example, postulate a time- Perhaps that the laws of physics reasons can now be advanced for like scalar field in addition to the haven’t ruled out an aether with postulating an aether.” spacetime metric. These so-called quite the certainty many of us have As Dirac pointed out, the Einstein-aether theories effectively been led to believe. But perhaps principle of relativity demands that assert the existence of a preferred also that a concept so seductive the perfect vacuum be isotropic frame, defined by a dynamical and intuitively plausible is almost in the sense of Lorentz, with all field, which breaks local Lorentz irresistible, and that the determined directions within the lightcone of invariance. This proposal has the human mind can find a way to bring any point being equivalent. The advantage of being testable, as it the idea into almost any theory. velocity of an aether would pick out predicts departures from standard Mark Buchanan The method of science Today, few would deny the the question “what is science?”, the way we do science — the central importance of science the answer will almost surely language, the instruments, to our lives, but not many of be that science is a process, a the methods we use — depends the general public would be way of examining the natural on clear presuppositions able to give a good account of world and discovering important about how the world works. what science is. To most, the truths about it. In short, the Modern science is full of word probably brings to mind essence of science is the things that cannot even not science itself, but the fruits scientific method. be observed at all. At the of science — the pervasive That stirring description most fundamental level, it is complex of technology that suffers from an important We don’t really impossible to observe nature has transformed all of our shortcoming: we don’t really without having some reason lives. However, science might know what the scientific method know what to choose what is worth also be thought to include the is. There have been many the scientific observing and what is not vast body of knowledge we attempts at formulating a general method is. worth observing. Once one have accumulated about the theory of how science works, makes that elementary choice, natural world. There are still or at least how it ought to work, Bacon has been left behind. mysteries, and there always will starting with Sir Francis Bacon. Science, it turns out, is be mysteries, but the fact is that, His idea, that science proceeds whatever scientists do. That, by and large, we understand how through the collection of of course, is not an adequate nature works. observations without prejudice, philosophical description, but it But science is even more has been rejected by all serious may be the best we can do. than that. If one asks a scientist thinkers. Everything about David Goodstein