The Confucian sages were fond of saying, “To understand what is far away, investigate the near at hand.” By this they meant that to comprehend the principles of “distant” phenomena such as statecraft and political conflict, we start by looking at our own emotions and thoughts: our immediate relationships, with family and friends and colleagues, and the daily situations in which we have to make decisions, tell us all we need to know about grander human things. If we do not understand ourselves and those around us, Aristotle and Thucydides can teach us nothing. Thus the Greek dramatists, Jane Austen, and Russian novelists saw clearly that what we need to know about human living can be found in a single family.
Nowhere is the principle of “understanding the far away by looking at the near at hand” more exquisitely realized than in the work of those early modern scientists who asked, What is our universe made of, and why is it the way it is? To grasp the principles of planetary motion, Kepler looked at magnets, muscles, river current, ferries, pullies, sausages — not just as analogies, but as examples of the same laws that govern heavenly bodies. Simlarly, the early chemists, like Boyle and Priestley, interrogated the very constitution of material reality with equipment for the most part no more complicated than what we could set up in our own kitchens. If the underlying constituent elements of the universe are finite and present everywhere, and if their changes in state (from solid to liguid to gaseous) are dependent on pressure and temperature, and if their relationships with each other are fixed and intelligible, then what happens on the surface of a planet such as Jupiter should be no more obscure to us than what happens before our eyes at every moment. Indeed, skillfully conducted experiments at one’s own stove will reveal as much to us about what the universe is as a trip to Jupiter will. The secrets of the entire universe are thus right in front of us, if only we were able to open them with a few good theoretical keys.
Antoine Lavoisier’s Elements of Chemistry (1790; Dover) presents us with some of these keys. In each chapter of this remarkable book he investigates common substances, often breaking them down into their primary constituents and then re-synthesizing them. He is a strict materialist about these constituents: all matter has the quality of weight, and no matter is ever destroyed or produced out of nothing. Thus, when a given substance is heated in air, or combined with another substance by heating or dissolving, both substances might be decomposed and emerge as new entities, but in every case the beginning weight and ending weight of the whole will stay the same, and from this equality we should be able to figure out the quantities of the constituent substances. A simple but powerful example of this occurs in chapter 8 of part 1, where Lavoisier proves in about ten pages that water is not an element but a compound, and he also identifies its components. Since we are all children of Lavoisier, we assume that we already know this — but how do we know this? How did he know it?
The exposition is made through four experiments, which I will summarize. The first three use the following set-up, as drawn by his wife (who did his experiments with him!). Note that Lavoisier (or the Lavoisiers) not only conducted experiments, but also conceived the requisite equipment and had it all specially made.
In Experiment 1, a known quantity of distilled water is put in vessel A and heated in furnace VVXX. It evaporates, passes through the tube EF, which is also kept heated in a furnace, and ends up in vessel H, where it condenses. Amazingly, there is the same amount of water at the end as at the beginning: nothing is lost and nothing gained in this process.
In Experiment 2, a fixed amount of charcoal is placed in tube EF and water in vessel A. These are heated. The water evaporates, and passes over the charcoal as steam. At the end, when the charcoal has disappeared, we find in vessel H a mixture of two gases, which Lavoisier has shown us how to separate. One is “carbonic acid gas,” formed from the carbon of the charcoal and oxygen disengaging from water; and the other is a very light unknown gas, which he will name “hydro-gen” because it forms water. We already know how to test for oxgen and carbonic acid gas, but hydrogen is new. The resulting combined weight of the two gases is the same as the combined weights of charcoal and oxygen at the beginning, and we can infer from these weights that the water we had at the beginning was a combination of hydrogen and oxygen in a ratio of 13.7:72 by weight. This itself is a remarkable discovery, but Lavoisier is not content: for instance, can we be certain that the new gas hydrogen was not in the charcoal?
In Experiment 3, instead of charcoal Lavoisier places iron in tube EF. This time, when all the water has evaporated, we find of course no carbonic acid gas, but there is a known amount of the new light gas in vessel H; in addition, the iron has turned into what we have learned to recognize as black oxide, and has gained in weight. A determinate quantity of oxygen has combined with the iron, and by subtracting the original amount of iron from the final weight we infer that the ratio of hydrogen to oxygen in our initial quantity of water is 15:85 by weight, which is close enough to the ratio found in Experiment 2.
Thus water is not one thing, but in fact two things in a fixed ratio. Lavoisier is not content with analyzing water into its parts, so now he takes these parts in the ratio 15:85 and, in Experiment 4 (which I will not go into here) synthesizes hydrogen and oxygen to make water. Just as a mechanic shows that he understands what a specific machine is by being able to take it to pieces and reassemble it, Lavoisier has tested his understanding of water by analysis and synthesis. In being so detailed in describing his apparatus, he has also shown us how to make certain for ourselves that we know what water is.
There is no space here to go into other fascinating byways of this book, including the culmination of the discovery of oxygen and the identity of combustion, oxidation, and respiration. Even if the revolutionaries who guillotined Lavoisier had also destroyed all of his writings except this chapter, the chapter alone would still be momentous in its impact on human thought — for had it not been a dogma of every culture that water is an element? How could something so ubiquitous and so essential for life not be an element? Does the mechanical decomposition and recomposition of water not demystify it completely, and put it on the banal level of other things that can be broken down and artificially recreated? Water in these ten or so pages has been demoted from divine status into a compounded object on the level of all other compounded objects, and what is fundamentally “real” about it turns out to be two elements not immediately available to our senses but scientifically inferred.
Wait a minute, says the skeptic: this pure water composed of 15 parts hydrogen and 85 parts oxygen exists only in the chemist’s lab — or in bottled water originating from a chemist’s lab. The water that we encounter in our lives is characterized by variation: the water from my tap, the water in Lake Michigan, the water in a mountain lake at 13,000 feet, the water in the Rio Grande, are all very different — in appearance, taste, constitution, behavior. Each one of these is also different from moment to moment, affected by the sun’s position in the sky, the moon, changes of pressure and temperature, and all those geological and biological beings that interact with it. Even my tap water is never the same on two successive days. Even the water in Lavoisier’s vessel H has among its many conditions Lavoisier’s theory of chemistry and his skill in experimentation. In our experience, too, of “water” — the warm shower on our neck, the boiling water we pour onto our coffee, the myriad forms and patterns of water in a mountain stream as it flows, icicles on a pine tree and the very different icicles on an oak tree, the rain clouds above us — it comes into our view as an infinitude of different beings, constantly surprising and beautiful. How could water simply be a mixture of hydrogen and oxygen? — just as my car simply is not a combination of metal and plastic. Water is its own being, with myriad expressions of its own life. Analysis and synthesis have not demystified it.
Lavoisier has too complex a mind to be a reductionist, and he might find it all the more wonderful that something as mysterious as water can be analyzed and synthesized into two simpler components (although hydrogen and oxygen have their own vast enigmas). The multifarious workings of water in our experience are truly how water appears to us, but by virtue of what (my deat Meno!) are all these identified as “water”? Beneath the appearances is a substratum made of elementary substances, and these substances follow their own rigid laws of changes of state based on temperature and pressure, and inescapable fixed affinities with other substances. There are cycles going on behind our appearances — just as behind the appearances of weather from day to day there are determinable meteorological cycles. Our experience may not tell us what things are, or it may reveal only a tiny part of what things are; in contrast to the phenomena of infinitely varied patterns and events, the substratum is eternal, cyclical, blind. Hydrogen and oxygen do not know about water, but water, as it were, obeys them. Could this also be a parable for our mental and emotional processes?