OBSERVATION AND ENLIGHTENMENT Lorraine Daston Introduction: The Age of Observation On 22 July 1757 the Genevan naturalist Charles Bonnet wrote to his Ber- nese colleague Albrecht von Haller: I have often revolved in my mind the plan of a work which I would have entitled Essay on the Art of Observing. I would have collected as in a tab- leau the most beautiful discoveries that had been made since the birth of philosophy. I would have shown the routes by which the great masters of the art had reached the sanctuary of Nature. I would have indicated the obstacles they had to overcome; the means they used; the different views offered to their minds [and] the use to which they put these. I would have demonstrated that the spirit of observation is the universal spirit of the arts and sciences. But, Monsieur, for a work like that I would have to have had your head. If your occupations ever allowed you to undertake [such a work], what an excellent logic it would furnish us with!1 Neither Bonnet nor Haller ever managed to write such a work on the art of observation,2 but Bonnet’s claim that “the spirit of observation is the uni- versal spirit of the arts and sciences” and that scientific observation was a new and powerful kind of logic would have been loudly echoed by many 1 “J’ai souvent eu dans l’esprit le plan d’un Ouvrage que j’aurois intitulé Essai sur l’Art d’Observer. J’y aurois rassemblé comme dans un Tableau les plus belles Découvertes qui ont été faites depuis la naissance de la Phylosophie. J’aurois montré les routes par lesquelles les Grands Maîtres de l’Art sont parvenus dans le Sanctuaire de la Nature. J’aurois indiqué les obstacles qu’ils ont eu à prendre; les moyens qu’ils ont eu à employer; les différentes vuës qui se sont offertes à leur esprit; l’emploi qu’ils ont sçu en faire. J’aurois fait voir que l’esprit d’Observation est l’esprit universel des Sciences et des Arts. Mais, Monsieur, pour un Ouvrage comme celui là il me faudroit votre Téte. Ha! Si vos occupations vous permettoient jamais de l’entreprendre, quelle excellente Logique ne nous vaudroit-il pas!” Charles Bonnet to Albrecht von Haller, Geneva, 22 July 1757, in Otto Sonntag (ed.), The Correspondence between Albrecht von Haller and Charles Bonnet (Bern 1983), 107 (transla- tion by L.D.). 2 At Bonnet’s urging, the Genevan pastor and naturalist Jean Senebier ended up writing the treatise: Jean Senebier, L’Art d’observer (Genève 1775), 2 vols. On the background, see Hans Poser, ‘Die Kunst der Beobachtung: Zur Preisfrage der Holländischen Akademie von 1768’, in id. (ed.), Erfahrung und Beobachtung: Erkenntnistheoretische Untersuchungen zur Erkenntnisbegründung (Berlin 1992), 99–119. © Lorraine Daston, 2013 | doi:10.1163/9789004243910_029 This is an open access chapter distributed under the terms of the CC BY-NC-ND 4.0 license.Lorraine Daston - 9789004243910 Downloaded from Brill.com09/29/2021 03:49:16AM via free access 658 lorraine daston Enlightenment savants, whether anatomists or astronomers, botanists or chemists, physicians or physicists. By the mid-eighteenth century, obser- vation was practiced, theorized, and celebrated in almost all sciences. “Never has so much been observed, as in our century.”3 The Enlighten- ment has been called the Age of Reason, but from the standpoint of the natural and human sciences, it would be still more accurate to call it the Age of Observation. During the Enlightenment, the prestige of scientific observation reached its zenith—as an art, a logic, a way of life. Never before or since has observation figured so prominently among cultivated scientific practices. Throughout the Latin Middle Ages, observatio was associated with shep- herds, sailors, farmers, and other outdoor workers who practiced what Cicero had called “natural divination”: waiting and watching for correla- tions between the stars, the weather, fat and lean harvests, the migration of birds, and other natural phenomena. Observation on this model was slow, cumulative, and anonymous, handed down orally from generation to generation in the form of proverbs like “Red in the morning, sailors take warning”. Only astronomical observations counted as part of the learned tradition and even these were made rarely; until well into the sixteenth century, European astronomers and astrologers relied largely on ancient observations. For medieval natural philosophers, observation was useful but not scientific: at best, it was a tool of the conjectural sciences like medicine and alchemy, condemned to deal with individual particulars rather than universal causes.4 Observation, since Antiquity linked with divination, was triply at the mercy of chance: the chance concatenation of causes, the chance opportunity of being at the right place at the right time, and the chance accumulation and transmission of past wisdom. For Aristotelian natural philosophers, chance was most unpromising material for genuine science. 3 Benjamin-Samuel-Georges Carrard, Essai qui a remporté le prix de la Société Hollan- doise des Sciences de Haarlem en 1770, sur cette question, qu’est-ce qui est requis dans l’art d’observer (Amsterdam 1777), 1. Carrard won the Haarlem Academy of Science’s prize for the best work on observation: Poser 1992 (note 2), 99–119; Jan Gerrit Bruijn, Inventaris van de Prijsvragen uitgeschreven door de Hollandsche Maatschappij der Wettenschappen 1753–1917 (Haarlem 1977). Senebier’s entry was awarded the Academy’s approbation and was probably more widely read (and translated) than Carrard. 4 See Katharine Park, ‘Observation in the Margins, 500–1500’, in Lorraine Daston and Elizabeth Lunbeck (eds.), Histories of Scientific Observation (Chicago 2011), 15–44. Lorraine Daston - 9789004243910 Downloaded from Brill.com09/29/2021 03:49:16AM via free access observation and enlightenment 659 For very different reasons, scientists since the mid-nineteenth century have also taken a jaundiced view of observation. Unlike their medieval predecessors, nineteenth-century men of science considered observa- tion to be essential to science. But they distinguished observation sharply from experiment, describing the one as passive and requiring minimal skill and the other as active and demanding the utmost ingenuity. The French physiologist Claude Bernard emphasized that “the mind of the experimenter must be active, that is to say he must interrogate nature and pose questions in every sense, following the various hypotheses that suggest themselves to him”, whereas the observer embodied “the passive senses that obeyed the intellect in order to realize an experiment designed with a preconceived idea in view.”5 The British astronomer John Herschel demoted observation to an amateur activity, to be discharged by an army of volunteers who would diligently “observe regularly and methodically some particular class of facts” and fill out standardized forms consisting of “distinct and pertinent questions, admitting of short and definite answers”.6 Twentieth-century philosophers of science took the devaluation of obser- vation in science a step further by positing a “neutral observation language” that barely differed from mere looking—a form of empiricism too rudi- mentary to be suspected of being “theory-laden”.7 Such condescension would have greatly surprised Bonnet, for whom observation was the highest, not the lowest form of scientific inquiry. For Enlightenment savants, observation was an elite learned activity, too lofty for unlettered sailors or shepherds and too demanding for amateur foot soldiers. Observation was decidedly active, fully engaging the senses and the intellect; observation and experiment were intertwined, not opposed. True observers were born, not made: “Depending on the kind of observa- tions in question, it is necessary that he [the observer] have clear-sighted eyes, very sensitive touch, a good nose, a delicate palate, and keen hearing. 5 Claude Bernard, Introduction à l’étude de la médecine expérimentale [1865], ed. by François Dagognet (Paris 1866), 52–54 and 71. 6 John F.W. Herschel, A Preliminary Discourse on the Study of Natural Philosophy (reprint of 1830 edn., Chicago 1987), 131–134. Herschel’s vision of centralized networks of standard- ized volunteer observers was to some extent realized in nineteenth-century meteorology: Fabien Locher, Le Nombre et le temps. La météorologie en France (1830–1880), dissertation, Ecole des Hautes Etudes en Sciences Sociales, 2004; Katharine Anderson, Predicting the Weather: Victorians and the Science of Meteorology (Chicago 2005). 7 For a brisk, perspicuous account of the philosophical positions in the mid-twentieth- century anglophone discussion of scientific observation, see Ian Hacking, Representing and Intervening: Introductory Topics in the Philosophy of Natural Science (Cambridge 1983), 167–185. Lorraine Daston - 9789004243910 Downloaded from Brill.com09/29/2021 03:49:16AM via free access 660 lorraine daston He also needs dexterity, sagacity, and intellectual penetration, which are gifts of nature that can be more or less developed but not acquired by art.”8 Throughout the long eighteenth century, observation featured prominently in the titles of learned books and articles; its prestige sur- passed that of both experiment and deduction; it was the yardstick by which savants took each other’s measure; it was even possible to become a “genius of observation”. My aim in this paper is to reconstruct what scientific observation meant in precept and practice for Enlightenment savants like Bonnet, von Haller, and a host of other citizens of the eighteenth-century Republic of Letters. Between circa 1660 and 1830 observation reigned supreme in the natural and human sciences: cultivated as a practice, analyzed as a logic, embraced as a vocation. How did observation rise to such heights after centuries of learned neglect? How were perception, attention, judgment, and memory schooled to craft an observation? Who was the observer and what demands were made on a life dedicated to observation, which noto- riously disrupted diurnal rhythms, constrained socializing, and endan- gered health? Above all, what kind of knowledge did observation promise; in other words, how could observation serve, in Bonnet’s phrase, as an “excellent logic”.