The Historia densi et rari, published posthumously in 1658, is probably Francis Bacon’s most complex natural and experimental history. It contains observations and experimental reports, quantitative estimates and tables, and theoretical and methodological considerations, in a structure which has never been fully investigated. I provide here a fresh reading of this text from the perspective of scientific practices. I claim that Historia densi et rari represents a quantitative and instrumental investigation assembled with the help of Bacon’s philosophy of experiment as developed in the Novum organum. I first discuss the role played in the Historia densiet rari by the various instances of special power in delineating the object of research. I then analyze the ways in which a special class of instances of special power, the “mathematical instances,” are used in the Historia densiet rari to make the inquiry both more precise, and more abstract. Bacon used mathematical instances to transform traditional recipes of pneumatics into quantitative, more general investigations into universal motions and processes. Finally, I discuss two examples of scientific practice at work: the attempt to use instruments to gradually define and clarify “proper” (i.e., scientific) notions of “rarefaction” and “condensation,” and the redefinition of a metaphysical concept (plica materiae) in instrumental and operational terms.
This paper claims that one way to bridge the gap between Francis Bacon’s speculative philosophy and his natural historical and experimental investigations is by looking at his peculiar top-down strategy of measuring Nature. Key to this strategy is the construction of perceptive instruments, i.e., devices “subtle enough” to detect and map natural limits, powers and virtues. In this paper, I discuss some of Bacon’s ideas for the development of perceptive instruments, and I show how his particular investigative strategy leads to the construction of an interesting and insufficiently investigated operational vocabulary. I focus on two particular terms of this vocabulary, “orbs of virtue” and “perception.” I show that, although originating in a natural-philosophical context, both terms acquire new, operational meanings in Bacon’s late natural histories. They vindicate the use of instruments and provide the necessary tools for a complex and interesting top-down approach to measuring Nature.
Observations, experiments and inquiries into the world of plants figure prominently in Francis Bacon’s Sylva Sylvarum. My purpose in this article is to offer a survey of this very rich and relatively under-investigated natural historical material, with the purpose of showing two things. First, I show that these inquiries unveil a sophisticated instrumental approach. Bacon treats plants as (al)chemical laboratories in which one can investigate the fundamental processes of nature and the continuous ‘pneumatisation’ of matter. A detailed examination of this instrumental approach can shed important light upon Bacon’s reductionist strategies of explanation. Second, I show that some of the experiments with plants recorded (or merely suggested) in the Sylva Sylvarum uncover several layers of theoretical vocabulary. In this experimental context, key concepts of Bacon’s natural philosophy are further refined and acquire new meanings.
At various stages in his career, Francis Bacon claimed to have reformed and changed traditional natural history in such a way that his new “natural and experimental history” was unlike any of its ancient or humanist predecessors. Surprisingly, such claims have gone largely unquestioned in Baconian scholarship. Contextual readings of Bacon's natural history have compared it, so far, only with Plinian or humanist natural history. This paper investigates a different form of natural history, very popular among Bacon's contemporaries, but yet unexplored by contemporary students of Bacon's works. I have provisionally called this form of natural history 'Senecan' natural history, partly because it took shape in the Neo-Stoic revival of the sixteenth-century, partly because it originates in a particular cosmographical reading of Seneca's Naturales quaestiones. I discuss in this paper two examples of Senecan natural history: the encyclopedic and cosmographical projects of Pierre de la Primaudaye (1546–1619) and Samuel Purchas (1577–1626). I highlight a number of similarities between these two projects and Francis Bacon's natural history, and argue that Senecan natural history forms an important aspect in the historical and philosophical background that needs to be taken into consideration if we want to understand the extent to which Bacon's project to reform natural history can be said to be new.