Within Aristotelian philosophy, imperfect mixtures occupy a singular place: they are the only bodies that do not have a substantial form of their own. This entails that bodies such as meteors and other meteorological bodies – which qualify as imperfect mixtures – are in between pure elements and complete mixtures, nevertheless retaining the form of the elements. While explaining and classifying imperfect mixtures was a reason for disagreement even among Aristotelians (see Petrescu 2014), it raised even bigger problems for those who did not rely on substantial form to explain the difference between perfect and imperfect mixtures. Francis Bacon is one such author.

In Sylva sylvarum, as part of a discussion about concoction and other similar alterations of bodies (in The Works of Francis Bacon, ed. Spedding, Ellis, Heath, vol. II, p. 613), Bacon writes:

In versions, or main alterations of bodies, there is a medium between the body as it is at first, and the body resulting; which medium is corpus imperfecte mistum, and is transitory, and not durable; as mists, smokes, vapours, chylus in the stomach, living creatures in the first vivification: and the middle action which produceth such imperfect bodies, is fitly called (by some of the ancients) inquination or inconcoction, which is a kind of putrefaction; for the parts are in confusion, till they settle one way or other.

One might argue that Bacon’s analysis of these topics is inspired by Aristotle’s Meteorology, IV, 3. It is not the aim of this post to analyse Bacon’s reception of the Meteorology (though this would be very interesting given that Bacon mixes here the discussion about the imperfectly mixed bodies from the first three books of the Meteorology with the definition and classification of concoction from the fourth book, and the inconsistence of the Meteorology was a topic of discussion among Aristotelian authors also). The aim of the blog post is to raise a few questions about how Bacon conceived of natural bodies and natural processes, and, hopefully, offer a few prospective solutions along the way.

What is striking about the Sylva passage just quoted is that Bacon classifies bodies that would have not have been grouped together in the Aristotelian natural philosophy as ‘imperfect mixtures’: mists, smokes, and vapours were traditionally the imperfect meteorological bodies, while chyle and the embryo were related to the processes of living or animate beings, and thus were typically explained through perfect mixtures and substantial forms. I would like to suggest that this is due to Bacon’s conceptualisation of natural processes and the entities involved in them. It might seem that Bacon is classifying processes in opposed pairs: concoction is opposed to inconcoction and vivification to putrefaction. But the fact that concoction is also opposed to putrefaction (since inconcoction is a type of putrefaction) makes us wonder if concoction should be similar to vivification. But what if instead of treating processes as distinct pairs of contraries, we looked at these processes as a continuum? Let me try to explain why this route might prove fruitful.

Bacon does not explain any of these processes in terms of forms (nor substance or accidents). Instead, his explanations are in terms of the pneumatic matter that resides in each body. For him, all visible bodies are composed of both tangible matter, which is gross, heavy, and inert, and pneumatic matter, which is subtle, light, and highly active. Because pneumatics want to escape the tangible parts and unite with their connaturals (which are located in the skies) they move within bodies thereby causing processes such as concoction, putrefaction, vivification, and liquefaction (if we are to be precise, the explanation of such processes ought probably to be qualified, since the diversity of processes is caused not only by the motion of the pneumatics, but also by the internal characteristics of the body within which the pneumatics move). Pneumatics moving within a body concoct and digest it. But when there is little to be digested, pneumatics try to escape. If they are within metals (compact bodies with very tiny pores), escape is (almost) impossible, and then liquefaction takes place. Within other bodies they find pores and escape. Those pneumatics that remain inside the body move incessantly in their attempt to escape. If their motion is confused and unordered, the process we see is classified as putrefaction. If the motion becomes ordered so that it can figure a new body, vivification takes place.

There are two ways in which we can understand putrefaction and inconcoction. Putrefaction is the dissolution of the previous body or the first stage of the vivification of a new body. If the motion continues in a confused way or the pneumatics leave the body, the body dissipates. The same goes for inconcoction: motion starts, but if it stops too soon, or if it is not strong enough, then the resulting body does not attain stability, and it dissipates. We see this in smokes and fumes, which disappear very quickly. In both these cases, if we could pause the processes of vivification and concoction, we could always observe these intermediary stages – putrefaction and inconcoction.

There are (at least) two remaining questions: (1) why does Bacon say that inconcoction is a kind of putrefaction, and (2) what is it that does not perfectly mix in these bodies, since, for Bacon, it is not the mixture of the four elements as it is for the Aristotelians? For the latter, an easy way out would be to say that it is the tangible and pneumatic parts that fail to be perfectly mixed. And although this would not be totally wrong, it is only part of the answer. Bacon never speaks about ‘perfectly mixed bodies’, but we can assume that they would be those bodies in which tangibles and pneumatics would be united for a long period, and, furthermore, the pneumatics would be in charge of these bodies' functions (even for metal and stone, if we conceive them as being generated and growing within the earth). But when the motion of pneumatics is too confused or too weak, they cannot come to be in charge of the body in question, and the temporary union is dissolved.

As for the first question, there are also both simple and more complex answers. We can say that inconcoction is similar to putrefaction in that it does not lead to a proper change (a mature body in the case of concoction, or a new body in the case of vivification). What distinguishes them are the existing qualities of the body they transform through their motion: some bodies can be matured through concoction, while others can be destroyed, leading to the formation of new bodies.

When dismissing substantial form, one must find another account both for natural processes, which are no longer substantial, and for accidental change. Bacon’s solution is to introduce the interaction between passive and active bodies. The motion of the active bodies, the pneumatics, is a continuous process caused by their constant desire to leave the body. This motion, combined with the qualities of the body, creates a diversity of objects. In analysing the natural processes, Bacon is interested in establishing transition phases between different processes. But one question still remains: when and in precisely what conditions do a confused or weak motion become ordered or strong enough to be classified as different processes?

Acknowledgments: I owe gratitude to Laura Georgescu for her insightful comments.