H2O, murkier than you thought

![Figure][1] I know that many scientists have little regard or appreciation for the relevance of the philosophy and history of science. If you are among them, Hasok Chang's Is Water H2O ? will change your mind. It may not change the way you do your experiments or write your grants. But it will change the way you review grants and papers, it will change the way you mentor your students, and it will certainly change the way you teach science. And that means it will change the way you think about science—as well as much of the educational, financial, political, and public relations mess it currently finds itself in. Chang is a philosophical magician—not a sleight-of-hand artist but a deft illusionist who forces you to rethink your commonsense knowledge of the world and how you believe it works. He takes a simple question, one that we all know the answer to—or think we do—and then shows us that our reflexive response to the question probably isn't correct. And more than that, he uses this simple little question to explore the whole of the way we pursue scientific explanations—and then just for kicks he suggests a radical new approach for doing science. ![Figure][1] PHOTO: HELEN FILATOVA/[ISTOCKPHOTO.COM][2] So, is water H2O? Of course it is. How do we know that? For most of us, it will be textbooks or teachers. I daresay that few if any of us have any direct experience of actually making water from hydrogen and oxygen; even fewer, of separating hydrogen and oxygen from water and counting up the numbers of atoms. Nonetheless, the formula may be the most accepted statement in all of chemistry. Indeed, it sits at the base of the so-called chemical revolution begun by Antoine-Laurent Lavoisier and his contemporaries in the late 18th century. It underlies ideas of atomic and molecular weight, of composition, of chemical bonding—the very foundational concepts of chemistry. It does not, as I suspect many of us think, underlie explanations of combustion, heat production, or reactions. In fact, those ideas were more the province of the banished phlogiston—the imponderable source of combustion and its slower counterpart, oxidation, or rust. But phlogiston, the conceptual basis of the work on gases by Joseph Priestley and Henry Cavendish, was vanquished by Lavoisier and his followers. All very ironic, since it was Priestley who discovered and first produced oxygen and hydrogen. Priestley called the remarkable gas dephlogisticated air; Lavoisier gave it the name oxygen. One should actually say the misnomer since “oxygen” means acid generator and was based on Lavoisier's incorrect proposition that all acids were formed of oxygen. Nonetheless, it was oxygen that made Lavoisier famous, and he in turn remains the source of several incorrect ideas about it—one of them being that water is H2O, in the sense that H2O is a complete description of water. Aside from the simple interest and fascination of how scientific facts come about, and how so-called scientific revolutions become historical events, Chang uses this example to show us that we scientists have a very bad habit of abandoning theories, systems, or programs prematurely, playing science as if it were a winner-take-all game. Using phlogiston and other similar cases, mostly from chemistry, Chang weaves a very convincing, if radical, argument: By abandoning theories and choosing a single favorite, for often unfounded reasons or reasons that may be as much sociological as scientific, we implicitly subscribe to a monistic view of science—in which there is always one, and only one, right answer. Not only is this probably incorrect, it is terribly limiting. Even if ultimately there is one correct answer, we are nowhere near ultimately in any of our science. So why adopt monistic views that are surely going to be at least partly wrong? There is no good reason that all of physics adopted Newton's views, except that they were very successful. And then, ultimately, they were wrong in some ways—time and space are not absolute even though we continue to teach our children a physics in which they are. Had we not been in such a rush to become devoted Newtonians, we might not have had to wait another 250 years to find out that time and space are relative and light speed is absolute. Chang argues for the position that science should be a pluralistic pursuit of explanation, that it can only benefit by being pluralistic, and that monism warps the effort in every way—from funding, to publishing, to teaching, to …, well, understanding. His pluralism is not a disguised relativism, nor is it an expensive luxury that will rob science of its focus. Rather, it provides benefits ranging from simple tolerance (with critical judgment) of ideas to novel applications due to integration of otherwise incommensurable systems. In a classic example from cutting-edge technology, he gives us the case of the global positioning system: By means of satellites kept in place by Newtonian physics and atomic clocks ruled by quantum mechanics and corrected by special and general relativity, this system maps the spherical surface of the round Earth on a geocentric grid, thus giving navigational advice to people on the ground from a flat-Earth point of view. And it all works beautifully. As obviously sensible as pluralism sounds, this project is nonetheless a very difficult one. That's because most scientists don't realize how monistic they and their fields are. Need I mention that the most modern biological field, molecular biology, has been dominated for 60 years by something called “the central dogma” (DNA makes RNA makes protein). Now “dogma” can't really be a term that scientists should be comfortable with—but it's in all our textbooks, we teach it to generation after generation of students, and we even say it without any trace of irony. Central dogma? Really? And it's not true. Chang is the most comprehensible, and often entertaining, writer of science that I have come across in some time. He does not shy away from either sophisticated chemistry and physics or higher-level philosophy, but rather makes them accessible. In a neat organizational trick, he arranges the book in five chapters, each divided into three sections. The first section of each chapter offers an introduction to the ideas in nontechnical terms designed for maximum accessibility. Directed at professionals, the second, more formal, section develops the ideas further in the context of current philosophical and scientific thought. But Chang's clear and elegant writing style makes even this accessible. In the third section, he attempts to confront the likely arguments against his thesis and offers counterarguments—often admitting, to his credit, that more remains to be done and that he doesn't have the complete answer or a prescriptive program. If you read nothing but the first section of each chapter, you will enjoy a short, coherent book and obtain a very good appreciation for Chang's radically sensible view of science practice. But if your experience is like mine, you'll read Is Water H2O ? from cover to cover. And then—once you give up on the idea that it is—you'll join the revolution. [1]: pending:yes [2]: http://ISTOCKPHOTO.COM