The book's central case study is Boyle's air pump—a complex, expensive, temperamental machine that produced a vacuum by mechanical action. Boyle invited gentlemen of the Royal Society to witness experiments: a bird dying in the evacuated chamber, a candle extinguishing, the Torricellian column dropping. The witnesses certified what they had seen, and their collective testimony constituted the vacuum as a scientific fact. Schaffer and Shapin showed that this process involved three forms of technology working in concert: the material technology of the pump itself, the social technology of gentlemanly witnessing (whose credibility derived from class position guaranteeing disinterestedness), and the literary technology of the published experimental report.
The controversy with Hobbes revealed the stakes. Hobbes did not deny Boyle's observations; he denied their interpretation. The effects Boyle attributed to a vacuum could be explained, Hobbes argued, by subtle matter in motion. The dispute could not be resolved by evidence because the evidence was compatible with both frameworks. What resolved it was the institutional triumph of Boyle's experimental community over Hobbes's philosophical method—a victory secured through the Royal Society's social prestige and political connections rather than through logical superiority.
The book's influence extended far beyond history of science, providing foundational concepts for science and technology studies: co-production (facts and instruments validate each other circularly), the social construction of scientific knowledge (communities certify what counts as knowledge), and the politics of demonstration (who gets believed depends on social position). Critics accused the authors of relativism—if all facts are socially constructed, how can any claim to truth be sustained? Shapin and Schaffer's response was that showing how facts are made does not unmake them; it reveals the social labor that makes reliable knowledge possible.
Leviathan and the Air-Pump emerged from Shapin and Schaffer's engagement with the Edinburgh 'strong programme' in sociology of scientific knowledge, which insisted that successful and failed knowledge claims should be explained symmetrically—through social interests rather than through correspondence to reality. The book applied this framework to a canonical episode in the Scientific Revolution, demonstrating that even foundational experimental results required social machinery to achieve the status of knowledge. The juxtaposition of Boyle's experimental reports with Hobbes's philosophical critiques revealed two incompatible epistemologies competing for dominance in seventeenth-century England, with the experimentalist victory establishing patterns that govern scientific practice to this day.
The vacuum was not discovered but constituted. Boyle's experiments did not reveal a pre-existing fact; they produced the vacuum as a scientific fact through coordinated deployment of material, social, and literary technologies.
Witnessing communities certify knowledge. The credibility of experimental demonstration depended on who witnessed it, with gentlemanly status functioning as an epistemic credential independent of technical expertise.
Instruments and facts validate each other circularly. The air pump's reliability was proven by the vacuum it demonstrated; the vacuum's reality was proven by the reliable air pump—a circularity that is the normal mechanism of knowledge production.
Knowledge disputes are resolved socially. The Boyle-Hobbes controversy was settled not by evidence triumphing over error but by institutional processes favoring experimentalism over philosophical demonstration.
Invisible labor sustains experimental systems. Robert Hooke and other operators built and maintained Boyle's apparatus, but their contributions were epistemically erased by conventions attributing knowledge to gentlemen.