Much has been written about seventeenth-century experiments and experimental philosophy. My paper for the CELFIS seminar of October 8 aimed at engaging with that tradition. In particular, I was concerned with the recent discussion by Peter Anstey of the so called BBH model of the experimental philosophy (BBH stands for the name of Bacon, Boyle, and Hooke). As a reaction to Thomas Kuhn and Peter Dear, Peter Anstey’s article provides a very nice introduction into the Baconian experimentation and its main developments in the second half of the seventeenth century. Both Boyle and Hooke engage with a form of experimentation that is labelled here “Baconian.” It is not, however, the purpose of this small blog post to engage with the details of Anstey’s article, but rather to try to complement his analysis with a new example of experimentalism that can be found in a completely different source. This is the case of the experimental work of the Cartesian natural philosopher, Jacques Rohault.

In my lecture, I’ve referred to two experiments that were performed by Rohault: with pneumatic devices, on the one hand, and with glass drops, on the other hand. It is well known that Boyle was the main contributor to the pneumatic or baroscopic experiments of the 1660s. Hooke was among the first to examine glass drops and to provide an explanation for both the production of the small glass objects and for the curious phenomena produced by those. Interestingly, Rohault deals with both of these issues in experimental terms.

Now, one might very well wonder why is important that a Cartesian philosopher was providing an explanation for some intriguing experiments; after all, he is a Cartesian, therefore a speculative philosopher (see the Otago blog here and here), and he would explain all phenomena according to the principles of Cartesian physics. Yet, this classification of seventeenth-century philosophers into “experimental” and “speculative” should not be an impediment in searching for explanations in one’s writings. But there is more than that and I argued in my paper that it is precisely Rohault’s experimental approach to the study of the two phenomena that would make difficult to draw a clear boundary between his work and the works of the most representative experimenters of the BBH model.

I have argued elsewhere that Rohault treats the study of the properties of the air in experimental terms. He does not simply jump from the conclusions derived in the general part of Cartesian physics (which is most often claimed that he does), but actively engage in experiments and observations.

With respect to the study of glass drops, Rohault is also concerned to perform all the needed observations before providing an explanation. This is also what Hooke did in his Micrographia.

As a tentative conclusion for this very sketchy blog-post, I claim that based on these two experiments, Rohault should be placed in the same context with Boyle and Hooke, so as a representative of the BBH model. If, on the contrary, one would like to point to his “Cartesianism,” then, one simply overlooks his experiments and this would raise new worries for the use of historical categories: if one dismisses some experimental practices only on the basis of placing the practitioner to one or another camp, then, the problem is not any more with the use of experiment in natural philosophy, but with the way various natural philosophies of the period were classified in our histories.