A New System of Chemical Philosophy Philip Ball Reflects on the Work of John Dalton, Father of Modern Atomic Theory

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COMMENT BOOKS & ARTS IN RETROSPECT A New System of Chemical Philosophy Philip Ball reflects on the work of John Dalton, father of modern atomic theory.

isual metaphors are often it tends to connote today. Yet his essential in science when book also represents an important you can’t see what you’re juncture for the philosophy of sci- Vstudying. The English chemist ence. It spoke to whether science John Dalton, born 250 years ago, should be based on empiricism or illustrated his atomic theory using explanatory hypothesis — a ques- IAN DAGNALL/ALAMY wooden spheres (pictured), drilled tion that had exercised Newton with holes for pins that enabled them and Robert Boyle in the seven- to be linked into clusters. But there teenth century. There was nothing are hazards to such mental props. By new in Dalton’s idea of atomistic the 1880s, students were so familiar matter; the question was whether with the spheres that one (taught to treat this as a useful conjecture by prominent advocate of atomic or as a reality. Antoine Lavoisier, theory Henry Enfield Roscoe) whose work on the proportions of declared: “Atoms are round bits of chemical combination was crucial wood invented by Mr Dalton.” to Dalton, had no time for such Today, the atoms Dalton pro- questions. Lavoisier insisted that posed in his seminal New System meditating on “ultimate particles” of Chemical Philosophy (1808) are was metaphysical — and fruitless. routinely revealed by microscopy So how did Dalton, a modest and crystallography. They are cor- teacher educated in Cumbrian ralled in electromagnetic traps, village schools and excluded from pushed around like marbles using Oxford and Cambridge for his scanning probe microscopes, even Quakerism, take an imaginative manufactured and monitored one leap that eluded distinguished at a time in superheavy forms using professors? Even if we admit some particle accelerators. No one mis- of the fairy dust of “genius” into an takes them for bits of wood. explanation, we shouldn’t discount Neither did Dalton. He articu- Dalton’s wide reading — from lated the ancient idea that matter John Dalton, painted in 1835 by Thomas Philips. Boyle and Newton to Claude Louis is built from fundamental particles Berthollet and Humphry Davy. He in a way that aligned it with the quantitative evidence is elusive. It is a risky strategy to also paid careful attention to the quantita- principles of chemical reaction elucidated in assert the physical reality of something not yet tive details of experiments by the likes of his the late eighteenth century. Those macro- observed (will dark matter really be particu- friend, Mancunian chemist William Henry, scopic rules, he said, stemmed from the sys- late?). But without such an image, a theory and Lavoisier. Dalton presented his atom- tematic combination of microscopic bodies: can seem little more than metaphysics. istic theory to the Manchester Literary and solid, massy and hard, as Isaac Newton had It is traditional to locate Dalton’s New Philosophical Society, of which he was sec- put it in a phrase Dalton was fond of quoting. System of Chemical Philosophy as a step — retary, between 1803 and 1805. Some of his Yet in a sense, even by the 1880s, atoms perhaps the greatest — in a long road to mod- papers were published in the society’s mem- were still not much more than Dalton’s model ern atomic theory that began with the ancient oirs, but he was urged to present them as a spheres. Because they remained unobserved, Greek atomists Leucippus and Democritus book, as he put it, in “the interests of science, several leading scientists refused to accept in the fifth century bc, and ended with the and his own reputation”. their reality, among them physicist Ernst nuclear atoms proposed by Ernest Ruther- The New System is one of those foun- Mach and chemist Wilhelm Ostwald. Some ford and Niels Bohr in the early twen- dational books that doesn’t say what considered atoms no more than an heuristic tieth century, then quantum theory you might think it should. It is mostly convenience: a crutch that the mind could and scanning probe micro- not about atoms at all. The first use to make sense of chemical transforma- scopes. The “philoso- 140 pages or so of Volume 1 tions. That is why, despite Roscoe’s misgiv- phy” in Dalton’s title dwell on heat and its effects, ings that Dalton’s wooden balls might mislead signified something students, the balls had a valuable role. They closer to a scientific The spheres that Dalton showed how visualizing an entity can help theory than to the used to demonstrate to cement the concept even while direct abstract reasoning atomic theory. MUSEUM OF MANCHESTER SCIENCE & INDUSTRY/SSPL

BOOKS & ARTS COMMENT

A New System whereas Volume 2 is of Chemical a detailed account of Philosophy inorganic chemical Books in brief JOHN DALTON R. Bickerstaff: 1808. compounds. Dalton’s atomic theory is con- Reductionism in Art and Brain Science: Bridging the Two Cultures fined to the five-page Eric R. Kandel Columbia University Press (2016) final chapter of the first volume. Here, he The sea-slug studies of Nobel-prizewinning neuroscientist Eric explains that the fixed stoichiometries of Kandel — which reveal the link between memory and synaptic chemical reactions — so much of element connection — are models of reductionist science. In this intriguing A combines with so much of B — can be treatise, Kandel finds methodological similarities in abstract art. By rationalized by supposing that the constitu- reducing image to colour, form or line, artists such as Piet Mondrian ent atoms unite into “compound atoms” of stimulated the brain’s “top-down processing” in the viewer, simple ratios, such as 1:1 or 1:2. The point encouraging ‘active seeing’. Kandel deconstructs this intricate dance is most famously and eloquently made in a between perceiver and perceived by way of recent neuroscience plate that shows sketches of these unions. An findings and deft analyses of seminal artworks. “atom” of water comprises one atom each of hydrogen and oxygen; an atom of ammonia is a 1:1 union of hydrogen and nitrogen (Dalton Weapons of Math Destruction uses Lavoisier’s term, “azote”, for nitrogen). Cathy O’Neil Crown (2016) The proportions are wrong — chemist Jöns While working as a Wall Street analyst during the 2008 crash, data Jakob Berzelius corrected many in the follow- scientist Cathy O’Neil realized how maths can fuel social problems. ing two decades. And in 1813, he proposed Her propulsive study reveals many models that are currently an alphabetical representation (for example, “micromanaging” the US economy as opaque and riddled with bias. H2O [sic]) in place of Dalton’s pictorial balls. These algorithmic overlords can taint policing and court sentences Dalton, with the conservatism common to with racial profiling, and exacerbate unemployment rates in poor trailblazers, declared this “horrifying”, saying communities. In an era when many people uncritically applaud the that the symbols “cloud the beauty and sim- power of big data, O’Neil argues for the dark side of the deluge to be plicity of the atomic theory”. His displeasure tackled through algorithm audits, transparency and legal reform. might have contributed to a stroke in 1837. The New System is not a new theory of chemistry. Among other things, it offers no Citizen Scientist: Searching for Heroes and Hope explanation for why atoms react. Roscoe in an Age of Extinction put his finger on it when he said that the Mary Ellen Hannibal The Experiment (2016) significance of Dalton’s theory was his pro- In this inside story on citizen science and biodiversity loss, Mary posal that each type of atom has a unique Ellen Hannibal meshes interviews with front-line scientists such mass. That made sense of the quantities in as James Estes (Nature 533, 318–319; 2016) with her own stints which elements were found to combine, monitoring California wildlife. Inspired by the likes of marine and offered the first general and fundamen- biologist Ed Ricketts (Nature 516, 326–328; 2014), she records tal distinction between one element and the starfish die-offs, meets the geeks who track deforestation, and plans next — what eventually became embodied a web-based supercommunity of citizen scientists to counter what in the idea of atomic number. many are calling the sixth great extinction. A cogent call to action. Yet it is the idea of atoms as the indivis- ible units of matter that stuck in the mind, because readers could see them on the A Brief History of Everyone Who Ever Lived: The Stories in Our Genes page. Dalton didn’t intend his pedagogical Adam Rutherford Weidenfeld & Nicolson (2016) diagrams of atomic unions — “compound Fifteen years ago, the first sequence and analysis of the human atoms”, or molecules as we’d now say — to be genome was published (E. S. Lander et al. Nature 409, 860–921; taken too literally. There’s no inkling in his 2001). A monumental surge in genetics followed. Science writer and book of molecular shape; the arrangements broadcaster Adam Rutherford rides that tide and traces its effects, of atoms in binary, ternary and other unions first focusing on how genetics has enriched and in some cases are purely notional, and when Dalton draws upset our understanding of human evolution, then examining the “water particles” packed into the crystalline revelations of recent findings, such as deep flaws in the concept of forms of ice, they too are spheres. race. Although digressive in the chapters on deep history, Rutherford All the same, visual representation of atoms unpeels the science with elegance. was surely the precondition for the emer- gence of a concept of molecular structure, with atoms in fixed spatial relationships, in Trillion Dollar Baby the mid-nineteenth century. Something Paul Cleary Biteback (2016) of this kind would surely have appeared Norway’s government pension fund could hit US$1 trillion in just whether or not Dalton had “invented” atoms four years. In this crisp economic history stretching back more than as wooden balls — but that innovation was four decades, journalist Paul Cleary charts how this middle-income more eloquent than its inventor anticipated. ■ Scandinavian country ensured that 90% of the cash flow from vast oil discoveries accrued to its government. But despite its record Philip Ball is a writer based in London. His of pragmatic fair-mindedness, Norway’s eagerness to excavate latest book is The Water Kingdom. environmentally sensitive reaches of the Arctic shows how its e-mail: [email protected] forward planning fails when it comes to climate change. Barbara Kiser