Abstract: STEVEN SHAPIN and SIMON SCHAFFER, Leviathan and the air-pump. Hobbes, Boyle, and the experimental life. Including a translation of Thomas Hobbes, Dialogus physicus de natura aeris, by Simon Schaffer, Princeton University Press, 1985, 8vo, pp. xiv, 440, illus., £43.00. In his History ofthe Royal Society ofLondon, published in 1667 as an explanation and defence ofmen who spent their time weighing the air and anatomizing beetles, Thomas Sprat threw out many striking analogies between contemporary politics and the activities he defended. The Society fitted perfectly with the spirit of reconciliation and tolerance supposed to characterize the Restoration: it forbade discussion of politics or religion; it limited dissent to matters about which agreement could be reached; it stuck to matters of fact; it promoted industry, sobriety, good judgment, and balance; it opposed enthusiasts, dogmatists, radicals, and sinners. Shapin and Schaffer have dilated and developed Sprat's analogies and metaphors with the persistence and prolixity of the Society's cynosure, Robert Boyle. Their argument may be distilled as follows. Boyle wished to set aside a "social space" (the term is theirs) for the cultivation of experimental philosophy; he also wanted to demonstrate to society at large how civic and religious dissent might be managed peacefully and productively; in fact, he wanted both, for, as Shapin and Schaffer claim, "solutions to the problem of knowledge are solutions to the problem of social order" (p. 332). They discern three "technologies" in Boyle's effort to establish his "experimental language" (p. 49), his "disciplined collective social structure" (p. 78), his "space . . . so securely bounded that dispute could occur safely within [it]" (p. 303), his "experimental form of life" (p. 314). The technologies were: the material, that is, experimental apparatus, of which the air-pump was the exemplar; the literary, or wordy descriptions of experiments performed, of the witnesses present and their reliability, and of the machines themselves; and the social, or rules of engagement in philosophical debate, the pre-eminence of the matter offact, and the down-grading or exclusion ofconjectures or theories about the causes and principles of certified phenomena. Withall, the experimental philosopher must be modest, open and flexible: "Till a man is sure he is infallible", Boyle wrote, "it is not fit for him to be unalterable." These "technologies" drew fire from the plentiful furnace ofThomas Hobbes, whom Shapin and Schaffer use as a detector of the aspects of Boyle's programme offensive to contemporaries who differed from him politically. Hobbes pointed out that the material technology leaked; that the literary technology, at least in respect ofthe testimony ofwitnesses, had no force ("no infinite number of grave and learned men" make certainty, "but authority"); and that the social technology misconstrued the nature of knowledge. By making the matter of fact, and not the underlying principle, the main object of investigation, one forfeits the chance at truth and certainty and has no reliable way to exclude serious and dangerous error. Boyle and his precious air-pump would be an ongoing peril as long as experimental philosophers waffled over the nature of the "vacuum". Hobbes knew from principle that a true void space, being immaterial, could not be; others not so guided, like the noisy Cambridge philosopher Henry More, and the demonstrator of witches, Joseph Glanvil, admitted the void, and imagined that Boyle's experiments proved the existence of spaces for angels and spirits to play in. Hobbes's dogmatism in natural philosophy was of a piece with his concept of the State. In philosophy, the force ofreason, working from sure principles in the style of Euclidean geometry, must compel assent; "who is so stupid", he asked, "as both to mistake in geometry, and also to persist in it, when another detects his error to him?" In the State, the King's authority should prevail over all dissent and dissenters in both civil and religious matters. Just here, loose talk about vacuums threatened the peace. For priests would set up as experts on the immaterial, and construct an independent base ofpower on the strength of their pseudo-knowledge, as they had in the past; and so bring about subversions and rebellions. The method ofcreating and certifying knowledge, and the problem of establishing social order, forced Boyle and Hobbes to sharply