“Experimental” versus “speculative” philosophy: Stephen Gaukroger’s uncharacteristic misstep in scientific revolution historiography and how to fix it

During the 46 years Stephen Gaukroger and I were disciplinary colleagues and sometime collaborators, we differed sharply on only one problem: Gaukroger's claim that from the late seventeenth century 'experimental natural philosophy' (E.P.) displaced 'speculative natural philosophy' (S.N.P.). He held that, in E.P., direct phenomenal outputs of experiments produced explanations, while in S.N.P., corpuscular-mechanical matter theory dictated the forms of explananda and the content of explanations. I always objected to Gaukroger's model in epistemic and historical terms. This paper argues (1) on neo-Bachelardian and post-Kuhnian grounds that phenomenalist revelations from experiments are not possible in human dealings with hardwares; (2) that explanation in natural philosophical systems, such as that of Descartes, was more fruitful than Gaukroger's model allows; and (3) that his E.P. cases from optics and aero-statics of phenomenalist breakthroughs are historically inaccurate. My replacement model eschews ruptures in favor of evolution of experimental natural philosophizing out of the pre-existing field of natural philosophy, leading to the crystallization of new experimental domains over the period 1660–1750. These domains appeared not as one-off phenomenalistic breakthroughs, but rather as sets of relatedly theorised experimental hardwares that emerged over time, the process occurring from within – not against – the natural philosophical field.