TEORIE VĚDY / THEORY OF SCIENCE / XXXVIII / 2016 / 3 ////// studie / article /////////////////////////////////////////// HENRY MORE'S "SPIRIT OF NATURE" AND NEWTON'S AETHER Abstract: Th e paper presents the notion of "Spirit of Nature" in Henry More and describes its position within More's philosophical system. Th rough a thorough analysis, it tries to show in what respects it can be considered a scientifi c object (especially taking into account the goals of More's natural philosophy) and in what respects it cannot. In the second part of this paper, More's "Spirit of Nature" is compared to Newton's various attempts at presenting a metaphysical cause of the force of gravity, using the similarities between the two to see this notorious problem of Newton scholarship in a new light. One thus sees that if Newton drew from Stoic and NeoPlatonic theories of aether or soul of the world, we need to fully acknowledge the fact that these substances were traditionally of a non-dualistic, half-corporeal, half-spiritual nature. Both More's "Spirit of Nature" and Newton's aether can thus be understood as diff erent attempts at incorporating such a pneumatic theory into the framework of modern physics, as it was then being formed. Keywords: Henry More; Isaac Newton; Spirit of Nature; aether; pneuma; gravitation Morův Spirit of Nature a Newtonův éter Abstrakt: Příspěvek představuje pojem Spirit of Nature u Henryho Mora a jeho pozici v rámci Morova fi losofi ckého systému. Důkladnou analýzou se pokouší ukázat, v jakých ohledech je možné jej (s ohledem na cíle Morovy přírodní fi losofi e) považovat za vědecký objekt a v jakých nikoli. Následně se pokouší na základě podobností Morova Spirit of Nature s Newtonovými pokusy o metafyzické vysvětlení příčiny gravitační síly nabídnout nový vhled do této v rámci newtonovských bádání zásadní otázky. Ukazuje se totiž, že pokud Newton čerpal ze stoických a novoplatónských teorií éteru a světové duše, je třeba vzít v potaz silně nedualistické, tělesně- -duchovní pojetí těchto substancí. Spirit of Nature i Newtonův éter by tak bylo možné chápat pouze jako různé pokusy, jak takovéto tradiční pojetí pneumatu začlenit do rodící se moderní fyziky. Klíčová slova: Henry More; Isaac Newton; Spirit of Nature; éter; pneuma; gravitace JACQUES JOSEPH Department of Philosophy and History of Science Faculty of Science, Charles University Viničná 7, 128 00 Praha 2 email / LePabouk@gmail.com 338 Jacques Joseph Introduction Th e main topic of my paper is going to be the "Spirit of Nature", a spiritual substance that, according to 17th century Cambridge Platonist Henry More, pervades the whole of the universe and moves inert matter in such a way as to bring about all sorts of phenomena that cannot be explained by purely mechanical laws. Th is topic may feel a bit out of place, since such a thing doesn't really look like a scientifi c object. Th at's why I am fi rst going to present a general description of More's metaphysical system and of the place of the "Spirit of Nature" in it, arguing that if we take into account the preoccupations of More and the interconnectedness of metaphysics and physics in that period, there defi nitely are respects in which the "Spirit of Nature" can be considered as a scientifi c object. In my analysis, however, it will also become apparent that the "Spirit of Nature" acts rather as a metaphysical ground for mechanicism than as a direct explanatory principle. Th is, as I shall argue, is one of the reasons why it didn't really have a place in the newly-formed physics of Newton and his followers. As such, it is only natural that the "Spirit of Nature" as a scientifi c object disappeared from scientifi c discourse before it ever really entered into it. In this sense, it can be put in parallel with Newton's aether theories and other attempts at providing a cause for gravity. In both cases we are looking at a metaphysical ground of science, the main diff erence being that while Newton pushes it into the background and focuses on mathematical formulae, for More, the "Spirit of Nature" is supposed to act as a full-fl edged explanatory principle. Paradoxically enough, it is Newton's aether that ultimately became a bona fi de scientifi c object and inspired a long tradition of ether theories in modern physics. Although my intention won't be to strictly claim any form of direct infl uence of More on Newton, I will try to develop A. R. Hall's claim that "only if Newton's metaphysical views are irrelevant to the writing of the Principia (and, we might add, of Opticks too) is it possible to deny to More any possible infl uence upon the transformation of the mechanical philosophy eff ected by Newton in these works."1 Th e parallels I am going to draw between More's "Spirit of Nature" and Newton's possible causes of gravity will, I believe, shed some new light on the question of how 1 Alfred R. HALL, "Henry More and the Scientifi c Revolution." In: HUTTON, S. (ed.), Henry More (1614–1687). Tercentenary Studies. Dordrecht: Kluwer 1990, p. 50 (37–54). Th is paper was created as part of the project "Renaissance philosophy and science" (GA ČR 15-0680S). 339 Henry More's "Spirit of Nature" and Newton's Aether much Newton drew from (and transformed) ancient Stoic and Neo-Platonic theories. I. Henry More's "Spirit of Nature" In Henry More's philosophy, two diff erent traditions of thought intertwine. Th e fi rst of these is Neo-Platonism, drawing from sources like Plotinus, Proclus or Ficino, while the other is the philosophical tradition of 17th century natural philosophy, especially its debates around mechanicism and the related threat of atheism. Although More was one of the fi rst to introduce Descartes's new philosophy to England, his opinion of it wasn't as uncritical as it might have seemed at fi rst. While he sees himself and Descartes as ultimately aiming for the same goal, "the one travailing in the lower Rode of Democritisme, amidst the thick dust of Atoms and fl ying particles of Matter, the other tracing it over the high and aiery Hills of Platonisme, in that more thin and subtil Region of Immateriality,"2 at the same time, when he sets out to write to Descartes as early as 1648, he fi nds he cannot agree with him on everything, writing: But indeed, illustrious Descartes, so as not to conceal anything, although I value very much the most beautiful bulk and essence of your Philosophy, I must however confess there are some minor things that elude me in the second part of the Principles that certainly my spirit is either too dull to understand or too repugnant to accept. Yet your most excellent Philosophy is in no way endangered in the main strokes thereof, since these scruples are such that while they may be judged deservedly to be false or uncertain, they do not reach to anything that is fundamental or essential to your philosophy; and it might very well stand on its own without them.3 Later on, when he composes his Enchiridion Metaphysicum in 1671, it is with the explicit intention of dismantling Cartesianism, as can be seen from More's correspondence during that time.4 2 Henry MORE, Collection of Several Philosophical Works. James Flesher: London 1662, Preface, p. xii (More's emphasis). 3 More to Descartes, Dec. 11, 1648. In: ADAM, C. – TANNERY, P. (eds.), Oeuvres de Descartes V. Paris: Léopold Cerf 1903, p. 238. 4 Cf. Alexander JACOB, Henry More's Manual of Metaphysics 1: Chapters 1–10 and 27–28. Hildesheim: G. Olms Verlag 1995, p. vff . 340 Despite the appearances, this is not an example of a philosopher doing an ideological U-turn, as has already been pointed out by others.5 More's fi rst and foremost concern had always been the fi ght against atheism. Originally, he perceived Cartesianism as a great weapon, showing the full strength and scope of the new mechanistic philosophy, while – more importantly – also showing all its shortcomings, leading to the postulation of immaterial substances, the most perfect of which (and the only necessarily existing) was God. In the end, however, he realized that Descartes gave too much attention to mechanicism and played down the importance of spiritual substances – most of all by not granting them extension (more on that later). What this meant was that although Descartes's intentions were undoubtedly good, his followers, seeing only the mechanical aspects of his philosophy and fascinated by them, fell into full-fl edged atheism. Th e only way to combat this threat, then, was to fully show all the weaknesses of Cartesianism and demonstrate the extent to which spiritual substances are needed to support mechanical philosophy. Simply put, More eventually realized that all those minor scruples he mentioned in his fi rst letter turned out to sway the whole system in a strongly atheistic direction, a thing he could not tolerate, no matter how highly he esteemed Descartes's mechanical genius. Th e fi rst step in reasserting the importance of spiritual substances was to grant them extension. For More, extension is a characteristic not just of physical matter but of any substance whatsoever, according to the principle that "there is no real Entity but what is in some sense extended."6 While Cartesians thought that spirits are present in space only by virtue of their power, for More, denying any actual spatial extension to them was tantamount to saying they don't exist at all. Th e problem was that Descartes perceived extension as tied to impenetrability. More thinks that there very well can be extended substances that can share their space with other substances – that is exactly what spirits and souls are! So while More accepts the general traits of Descartes's dualistic view of the world, he draws the dividing line in a quite diff erent way. All substances are extended, even having parts outside parts,7 with matter being divisible, impenetrable and absolutely passive, 5 Cf. Alan GABBEY, "Henry More and the Limits of Mechanism." In: HUTTON, S. (ed.), Henry More, pp. 19–36. 6 MORE, Collection of Several Philosophical Works, Preface General, § 12, p. xii. 7 In the Enchiridion Metaphysicum, chap. 27, § 14 (JACOB, Henry More's Manual of Metaphysics 2: Chapters 11–26. Hildesheim: G. Olms Verlag 1995, p. 111f.), More claims that the sensitive part of the soul is localized in the head, so that even if we grew an eye on our foot, it wouldn't be able to see, unless connected to the head with some nerves. Jacques Joseph 341 while spirits are indivisible, penetrable and the only possible source of activity in the world.8 Th is aspect of the passivity of matter as opposed to the activity of spirits is very important, as More is convinced that the interaction of purely passive pieces of matter very oft en falls short as an explanatory principle. Spiritual substances are needed to account for the behaviour of humans and animals – these all have individual souls – but they are also needed to explain a lot of other phenomena like gravitation, magnetism or thunder, lightning and rainbows. Th ese are all caused by a specifi c spiritual substance, namely the "Spirit of Nature". More defi nes the "Spirit of Nature" as "A Substance incorporeal, but without Sense and Animadversion, pervading the whole Matter of the Universe, and exercising a Plastical power therein according to the sundry predispositions and occasions in the parts it works upon, raising such Phaenomena in the World, by directing the parts of Matter and their Motion, as cannot be resolved into Mere mechanical powers."9 We see that – to use Alan Gabbey's phrase – the "Spirit of Nature" is basically defi ned as a "Spirit of causal gaps", an omnipresent spirit devoid of any free will or thoughts of its own that steps in whenever something happens that could not be caused by purely mechanical interactions. For example, let's take gravitation, a very puzzling problem for 17th century science. Hobbes's explanation was that gravitation is caused by tiny particles of ethereal matter moving randomly through space and constantly hitting other bodies thus pushing them down, while for Descartes, these particles were swirling in a vortex around the Earth. Th ese theories had to face a lot of problems. If the particles move in a more or less random fashion, how come they always end up pushing the objects down instead of pushing them in all directions more or less equally, cancelling each other out? How come, also, that the particles cannot be blocked by an especially smooth surface thus changing the angle at which things fall to the ground? If someone shoots a bullet up into the air, how come that the tiny and very light particles of aether still somehow manage to slow down the bullet and pull it back down, despite both its velocity and its density?10 According to More, these 8 See e.g. Henry MORE, Th e Immortality of the Soul, book I, chap. 3, § 1, p. 21 (in: MORE, Collection of Several Philosophical Works), or Henry MORE, Divine Dialogues. Joseph Downing: London 1713, dial. 1, §§ 29–30, p. 61ff . 9 Th e Immortality of the Soul, book III, chap. 12, § 1 (in: MORE, Collection of Several Philosophical Works, p. 193; emphasis omitted). 10 Th ese common objections are formulated by Henry More e.g. in Th e Immortality of the Soul, book III, chap. 13 (MORE, Collection of Several Philosophical Works, p. 196ff .). Henry More's "Spirit of Nature" and Newton's Aether 342 are all valid objections. Th e bullet should indeed continue fl ying straight up into space (More reports this has even sometimes been observed with cannonballs), a suffi ciently smooth mirror should indeed defl ect the aether thus changing the direction of gravitation, and most of all, the random movement of the particles of aether should indeed be pushing in all directions equally, so that there wouldn't be any gravitation at all in the fi rst place, if everything went purely according to mechanical laws. Th e fact that things are not like this serves in itself as proof that there are some non-mechanical and therefore immaterial causes at work, namely the "Spirit of Nature" that acts as the vital force unifying the movement of the tiny particles so that things fall down to the ground.11 In the Enchiridion Metaphysicum, the most notable of More's works in this regard, a lot of other natural phenomena get a similar treatment. Th e modus operandi is the same in all cases, be it with pressure, tides, rainbows, magnetism or thunder and lightning. A mechanical explanation (most usually the Cartesian one) is presented, followed by several objections. Aft er More has shown the necessary insuffi ciency of the mechanical explanation, he concludes an immaterial cause has to be responsible, this cause being the "Spirit of Nature". In all these cases, then, it could be argued that the "Spirit of Nature" is presented as a scientifi c object, something that is brought in to explain a given phenomenon, to integrate it into a scientifi c framework. Yet at the same time, the "Spirit of Nature" doesn't seem to be doing that much explanatory work. Given the way the "Spirit of Nature" is defi ned, saying that it is the cause of this or that phenomenon doesn't really say anything more than that the laws of mechanics we have available fail to explain it. To repeat, the "Spirit of Nature" indeed acts as a "Spirit of causal gaps" that just steps in whenever we don't have a more satisfactory explanation. Th is problem becomes all the more evident when we consider how we know whether a given phenomenon should be explained through mechanical laws or by the "Spirit of Nature". Th e best criterion at our disposal seems to be whether the phenomenon behaves regularly or not. From one point of view, this would mean that the "Spirit of Nature" acts according to certain laws and thus brings regularity into a world that would otherwise consist 11 Th e fact that some cannonballs have been observed not to fall back to the ground is due to the fact that at a certain distance from the surface of the Earth, the "Spirit of Nature" stops trying to pull the cannonball down and just lets it behave according to mechanical laws (Th e Immortality of the Soul, book III, chap. 13, § 6; MORE, Collection of Several Philosophical Works, p. 198f.). Jacques Joseph 343 only in bits of matter chaotically fl ying around and bumping into each other. On the other hand, we would be intuitively inclined to feel that these purely mechanical interactions have some regularity of their own – More himself speaks of mechanical laws, aft er all. Albeit mechanical interactions are not teleologically ordered, anytime two particles hit each other, their respective directions and speeds aft er the collision are determined in a law-like manner. Th is point of view leads to the opposite of what we have originally stated: it would then seem that the mechanical interactions are what behaves according to a set of laws and the "Spirit of Nature" steps in whenever these laws have to be circumvented. But this would transform the "Spirit of Nature" into some sort of permanent miracle-worker, leading to the question whether a law-like, permanent miracle can still be called a miracle. More, for one, does not seem to see the "Spirit of Nature" as permanently breaking the laws of nature but rather as constituting those laws. Th is is exactly one of the reasons why he so emphatically insists on the fact that the "Spirit of Nature" has no "Sense or Animadversion". Devoid of any free will, the "Spirit of Nature" does not choose to act in a certain way, it just does. Th at is why gravitation can sometimes cause a falling object to hurt an innocent person or why the "Spirit of Nature" can sometimes act against its own "interest".12 But if the opposition between mechanical interactions and the "Spirit of Nature" is the case of one set of law-like regularities opposing another (as I already pointed out, More is talking about "purely mechanical laws" as well), how do we tell into which category a given phenomenon fi ts? Later, we will see that this dichotomy is for More at least partially a false one but right now, unfortunately, the only answer we seem to have available is a circular one: some phenomena in principle cannot be explained mechanistically. Th is brings us back to the point I mentioned earlier – the "Spirit of Nature" only acts as a catch-all phrase for whatever we cannot explain otherwise. Or at least for whatever we think we cannot explain otherwise, as we can never really be sure whether an as of yet unknown mechanical explanation may not be coming. Concerning this, More was convinced that Descartes presented pretty much the most accomplished form of mechanistic philosophy possible. Th at is why, in the Enchiridion Metaphysicum as well as in other works, he feels that confuting Descartes (a fortiori in what he considers to be the most basic 12 Th at would be the case with Boyle's experiments with the vacuum air-pump, more on that below. Henry More's "Spirit of Nature" and Newton's Aether 344 mechanical phenomena) amounts to confuting mechanicism in general. In a letter to Hyrne (who came up exactly with this remark), he writes: As for your two objections, whereof the former is, Th at though these Mechanicall solutions be false, yet my inference of an incorporeall being from thence is not solid or necessary, because, we are not assured, but other Mechanicall solutions in time may be found that will truly solve these Phaenomena, I answer fi rst, Th at though this doth not amount to a perfect dry demonstration, such as is in Mathematicks, yet it is an exceeding high probability, scarce any higher in the guidance of ye aff aires of our life. For it seemes exceeding improbable that so excellent a Wit, the greatest Mathematician in Europe, and of such an eximious Architectonical Genius in Mechanicks as Cartesius, should faile in ye solutions of so many & so plain & simple Phaenomena as I have proved he has failed in, if ye presence it self of such Mechanicall solutions were not without foundation or a groundlesse presumption.13 Th us More really explicitly assumes that if Cartesianism fails, mechanistic philosophy as a whole fails as well and furthermore, that if these fail, the best alternative explanation is his "Spirit of Nature". But how does the "Spirit of Nature" work as an explanatory concept? What does such an explanation look like? Th ese are quite diffi cult questions related directly to a change in the perception of science that occurred during the Scientifi c Revolution. Th is is of course too vast a subject to cover in one paper so we will have to stick only to some general remarks. Th ese remarks are however crucial in understanding in what respects the "Spirit of Nature" was a scientifi c object and in what respects it was not. II. Th e "Spirit of Nature" as a Scientifi c Object During the Scientifi c Revolution, during More's lifetime and later on, there occurred an ideological shift as to what was expected of science. If we are allowed a little simplifi cation, this shift may be designated as a shift from natural philosophy, intrinsically tied to metaphysics, to experimental philosophy and later physics, expanding under Newton's famous motto, hypotheses non fi ngo. We can get a good idea of this shift if we compare Descartes and Newton. In some regards, Descartes has a very modern project of physics but he founds this project on metaphysical grounds. Th is leads to a big gap 13 More to Hyrne, 21 Aug. 1671, quoted in: GABBEY, "Henry More and the Limits of Mechanism," p. 31. Jacques Joseph 345 between the level of phenomenological description (e.g. of light refraction) and the more basic, ontological level where Descartes's mostly speculative models are supposed to explain these phenomena (his theory of rotating light globules). Newton, on the other hand, manages to unify the overall picture (thanks – at least in part – to his introduction of calculus) – but reaches this goal at the cost of downplaying the metaphysical aspect to the point that it ultimately disappears from physics (or at least from its explicit discourse).14 In this dichotomy, More stands fully on the side of Descartes. Although he is a member of the Royal Society, he is not really concerned with experimental results, he even shows open contempt for experimenting which, combined with his criticism of mechanicism, leads to a controversy with the more prominent members of the Society.15 While science was slowly becoming an endeavour to mathematically describe law-like regularities between measurable quantities standing in for various aspects of reality, More was much more interested in the ontological foundations of these relationships and in their metaphysical consequences. Th at is why, for example, in the chapters on the air-pump experiments and on hydrostatics of his Enchiridion Metaphysicum, he does not question the instruments, the techniques or the exactitude of the experimental results but the metaphysical lesson that we should draw from them. Th is framing of the debate is also the reason why he doesn't feel he needs to provide an explanation as to how the "Spirit of Nature" does what it does.16 Interpreting phenomena and experiments so as to show that they contradict mechanical laws is for him proof enough that some non-mechanical factor is involved and if it is non-mechanical, it must be immaterial (since all matter obeys the laws of mechanics). In the case of phenomena involving non-living matter, this immaterial principle obviously cannot be any individual human or animal soul. Furthermore, it cannot be God either, as that would lead to a crass and blasphemous 14 For a more detailed analysis, see Ladislav KVASZ, "Galileo, Descartes, and Newton – Founders of the Language of Physics." Acta physica slovaca, vol. 62, 2012, no. 6, esp. p. 548ff . and 573ff . (519–614). A more general description of this transformation can be found in Stephen GAUKROGER, Th e Emergence of a Scientifi c Culture: Science and the Shaping of Modernity 1210–1685. Oxford: Oxford University Press 2006, chap. 8–12. 15 Cf. HALL, "Henry More and the Scientifi c Revolution," esp. p. 40f. Also Robert CROCKER, Henry More 1614–1687. A Biography of the Cambridge Platonist. Dordrecht: Springer 2013, p. 151ff . 16 At least not in the same sense as more experimentally oriented philosophers would expect him to do, that is on a level analogical to mechanical explanations. As we will see later, that is because of the fact that More takes the "Spirit of Nature" to be a principally diff erent type of explanation than mechanicism is. Henry More's "Spirit of Nature" and Newton's Aether 346 immanentism (and possibly even to pantheism). So the only option left is a diff erent separate spiritual substance about which it can easily be proven that given the circumstances it must be omnipresent and devoid of any intelligence and free will, leading us to the notion of a "Spirit of Nature", quod erat demonstrandum. Yet such a systematic presentation of the introduction of the "Spirit of Nature" into More's system does not tell the whole story. Th e "Spirit of Nature" is a concept that came with a historical baggage that was very important for More. In a tradition going from Platonicism and Stoicism, through Plotinus, later Neo-Platonists and Marsilio Ficino up to More, we fi nd very strongly rooted the idea that the whole universe is a living organism and that as such, it has to have a soul. Furthermore, in order to be able to act on its body, this soul – just as any soul – needs an intermediary, a vehicle (vehiculum, okhema), usually termed spirit (spiritus, pneuma). Th is spirit is sometimes described in more "spiritual" (in the contemporary sense) terms, sometimes in more material terms, but it is in any way something in between soul and body, allowing for the interaction of the two. According to this doctrine, we all have such spirits, and so does the world.17 While these concepts could hardly be considered scientifi c and while More transformed them quite a bit, we need to be aware of this origin of the concept of "Spirit of Nature" when considering its place. More's primary motivation is metaphysical (the demonstration of the existence of souls) but it leads him into the domain of natural philosophy and, therefore, of science. Th us More's neglect of a more detailed study of the way the "Spirit of Nature" works is not a consequence of his using the concept intuitively, for he is not. It is only that the conceptual work done on the "Spirit of Nature" takes place within a diff erent context than that of experimental science. Th is is confi rmed if we consider the two most important occasions where he tells us more about the way the "Spirit of Nature" works. Th e fi rst would be a comment on the 13th chapter of the Enchiridion Metaphysicum treating of the problem of a wooden plate placed in a bucket full of water. According to mechanical laws, the gravity pulling all the water down should hold the wooden plate in place, yet the plate rises to the surface 17 Such a short summary is hardly exhaustive of the history of these concepts. More details can be found in Gérard VERBEKE, L'évolution de la doctrine du pneuma du stoïcisme à S. Augustin. Leuven: Desclée de Brouwer 1945; E. Ruth HARVEY, Th e Inward Wits. Psychological Th eory in the Middle Ages and the Renaissance. London: Warburg Institute 1975, or in Dodds's introduction and commentary to his translation of Proclus' Elements of Th eology (Eric R. DODDS – PROCLUS, Th e Elements of Th eology. Oxford: Clarendon Press 1963). Jacques Joseph 347 nonetheless. Aft er proving that all possible mechanical explanations fail, More addresses some objections presented by Christoph Sturm and as part of his answer, lays down some laws according to which the "Spirit of Nature" acts: First, that, although it [i.e. the "Spirit of Nature" – JJ] is one, it permeates all the parts and particles of the matter in the bucket. Next, it not only permeates but vitally activates them. Th ird, that this Spirit puts forth this vital energeian from a certain omniform essential life in itself in the parts or particles of matter, according to given circumstances, in various ways. Fourth, that this omniform life which contains the laws of moving the matter of the world is within individual points as it were – if one may say so – of this Spirit of Nature. Fift h, fi nally, since this Spirit is a certain essential or substantial life containing the laws of the motions of the matter of the world, and sympatheia & synenergeia agree with a spirit as such, and fi nally the said Spirit of Nature is created by the most wise God, from these things it is clear that all its operations, motions, sympathies and synergies are so constituted as, according to certain general rules of the universe, God himself has foreseen that they will be.18 According to this and to some later remarks as well,19 we thus see that the "Spirit of Nature" really acts as a (at least vegetative) soul, making non-living matter alike to a living body, therefore providing a very diff erent sort of explanation than what later experimental philosophers would perceive as scientifi c. Th e second insight into the way the "Spirit of Nature" works is provided collaterally, as part of the debate about action through contact. Besides all the phenomena already mentioned, More points out one more question that mechanicism can't even ask, let alone answer, namely, how does mechanicism itself work? If we take a collision between two particles – the paradigm example of mechanical interaction and the basic explanatory principle of mechanistic philosophy – the fact that a transmission of motion between the two particles occurs should not be taken for granted, thinks More. How is such a thing possible? As most mechanistic philosophers would agree, matter is inert and passive but how exactly are we to understand this passivity? As opposed to the Cartesian conception of passivity as the inability 18 Enchiridion Metaphysicum, Scholia to chap. XIII, sec. 4 (Alexander JACOB, More's Manual of Metaphysics 2, p. 75). 19 E.g. "[the Spirit of Nature], with a corporeal instrument as it were, presses the bottom of the bucket, [...]; the Spirit of Nature, I say, and the watery particles, as if one living, not mechanical, entity, act on the bottom of the bucket." (ibid., p. 76). Henry More's "Spirit of Nature" and Newton's Aether 348 to generate any new motion (only conserving the quantity of it that God has imparted to the world), More believes the absolute passivity of matter simply to mean that a particle all by itself could never transmit any of its motion at all. Th e fi rst mention of this problem can be found as early as 1649 in a letter More sent to Descartes. Th ere, he follows up with one more objection: in Descartes's metaphysical system, motion (just as rest) is a mode of substance and it is therefore quite unclear just how could either of them simply "jump" from one substance to another.20 At the time of this correspondence, More was still very much in his earlier, Neo-platonic period and his solution to this problem refl ects that. He proposes an emanationist theory in which there is no such thing as non-living matter – what we usually call body "is really a stupefi ed and sottish life, inasmuch as [...] it constitutes the last and faintest shadow and image of the divine essence, which I take to be the most perfect life."21 Th e problem is thus solved, as there is in fact no transmission of motion and it is the "sottish life" of the particle that allows it to set itself into motion upon being hit. Later, More himself grew dissatisfi ed with this solution because such a vitalism could easily create the impression that matter all by itself is enough to explain all forms of life thus threatening the belief in immaterial substances and God.22 Th e new explanation of this "action through contact problem" that More brings to the table is – again – the "Spirit of Nature". Th is of course changes completely the dynamic between explanations by mechanical laws and by the "Spirit of Nature" and More himself admits this, confessing that he is "abundantly assured that there is no purely Mechanicall Phaenomenon in the whole Universe."23 Th is heavily impacts both the question of distinguishing between mechanical and non-mechanical phenomena and the just mentioned analogy of the "Spirit of Nature" as if "enlivening" the non-living pieces of matter. While in so-called mechanical phenomena, the interaction of colliding pieces of matter may provide some sort of explanatory intermediary level, they are ultimately caused by the "Spirit of Nature" as well. On this intermediary level, a mathematical description may be available – that would be Descartes's mechanical laws, but that would also later be e.g. Newton's law of gravitation. As such, mechanicism may very 20 More to Descartes, 23 Jul 1649, in: ADAM – TANNERY (eds.), Oeuvres V, p. 382ff . 21 More to Descartes, 23 Jul 1649; English translation taken from Jasper REID, Th e Metaphysics of Henry More. Dordrecht: Springer 2012, p. 247. 22 Th is change is related to the need to defend Christianity against a new threat, namely Spinoza's (perceived) divinization of matter. 23 MORE, Divine Dialogues, Th e Publisher (More) to the Reader, p. viii (emphasis omitted). Jacques Joseph 349 well give us very exact predictions as to what is going to happen in some experimental setup but what is important for More is that if we want to know how it happens (on a metaphysical level), mechanicism cannot but remain silent and the real answer is going to be that it is the "Spirit of Nature" that "vivifi es" and orders pieces of matter and their respective movements in such a way that makes the mechanical description possible.24 More even considered his theory of the "Spirit of Nature" to be open to (indirect) experimental verifi cation. Th e aforementioned confutations in the Enchiridion Metaphysicum are not all on the level of metaphysical speculation. Th e chapters 12 to 22 are, among others, full of examples where More overcomes his dislike of experiments and gets into a very detailed analysis of experimental results to show how other, mechanistic, theories lead to consequences that blatantly contradict measured outcomes. As I already mentioned, More's method is mostly negative – he only shows that other theories fail to conform to the experience of our senses – but indirect as it may be, from More's point of view, this still is an experimental verifi cation of the existence of the "Spirit of Nature". In another famous example, he is convinced experiments prove that the "Spirit of Nature" has no free will, as it can sometimes work blindly against its own interest. For example, when we place an empty tube bottom up in water and close down the hole with a valve, the "Spirit of Nature" wants to balance up the diff erence of pressure. Yet, in trying to do so, it pushes water against the valve, thus preventing itself from accomplishing the very thing it tries to do. Th e laws according to which the "Spirit of Nature" acts in these cases are "certain general plastic reasons implanted in it by God and most useful to the common good of the universe and destined to it, and suffi ciently accommodated to the end towards which they aim in the ordinary course of Nature."25 But in such experiments, the "Spirit of Nature" is beset and assailed by the ludicrous artifi ces and useless curiosities of the human mind, and is drawn or provoked by irritation to put forth the power of some general plastic reason in circumstances thought of and put forward perversely and sharply, [so] it is most wisely that, in applying those general laws of motion on a given occasion, it is ensnared and impeded so that it does not 24 As we can see, with the only diff erence of replacing activity inherent to matter by the "Spirit of Nature", More's later position on this matter is quite similar to the one presented in the correspondence with Descartes. 25 Enchiridion Metaphysicum, Scholia to chap. XIII, sec. 15 (JACOB, More's Manual of Metaphysics 2, p. 91). Henry More's "Spirit of Nature" and Newton's Aether 350 attain the end to which those very laws naturally tend. All of which prove not, certainly, that the Hylarchic Principle [i.e. the "Spirit of Nature" – JJ] is nothing, but that it is not endowed with any counsel or reason or free judgement.26 Yet even from these considerations it is pretty clear that the experimental verifi cation More was working with is a bit diff erent from what we would usually expect. Th e "Spirit of Nature" was not for More a scientifi c object in the sense of being an object of scientifi c research. Th at is because More was not a physicist or a natural scientist, he was a metaphysician or, at best, a natural philosopher. Yet in natural philosophy, metaphysics and natural science are very oft en related, especially in More's time, and the "Spirit of Nature" fi nds itself exactly at this point of junction. Th at is, I believe, what creates this sense of tension when speaking of the "Spirit of Nature" as a scientifi c object – even in the fi eld of science, More's motivation is always metaphysical. Yet insofar as the metaphysical foundations of science are a part of it, we have to consider the "Spirit of Nature" a scientifi c object; not necessarily something that science examines, but most defi nitely something that contributes in a non-trivial way to how science is structured. If we then widen our view further, we may appreciate in which ways the "Spirit of Nature" impacts the overall shape of More's metaphysical and natural philosophical system. First of all, there are the obvious theological implications – as has already been said, defending the existence of God was one of More's leitmotivs and proving the existence of spiritual substances in general was the fi rst step in doing that. More generally, the "Spirit of Nature" served in delimiting More's overall metaphysical position. For one, he was very much aware of how dangerously close to pantheism his system may seem to some and the "Spirit of Nature" was defi nitely one of the tools that allowed More to subtly navigate his position between extremes that he wanted to avoid (like pantheism or materialism). On a less metaphysical note, the "Spirit of Nature" allowed More to group a certain set of phenomena by postulating a common, hidden cause for them. In this context, it should also be noted that most of the phenomena concerned were notoriously problematic for 17th century science (like gravitation or magnetism) and besides theories like those of Descartes (of gravitational vortices or magnetic effl uvia), a lot of explanations considered were non-mechanistic (Kepler's or Gilbert's, to cite a few). All things considered, More's spiritualistic theory was not necessarily worse than any of these. 26 Ibid. Jacques Joseph 351 III. Newton's Aether To resume the fi rst part of my paper, I tried to present the position of the "Spirit of Nature" within More's system and to show why and how it in fact worked as a scientifi c object. Th e "Spirit of Nature" grouped a set of phenomena and provided a unifi ed explanation for them, one More believed could be confi rmed by experimental data. At the same time, I have shown in what respects these reasons do not correspond to the expectations of modern science. Th ese stem mostly from the sort of explanation the "Spirit of Nature" provided. For More, explanations in natural philosophy had to lead back to metaphysical causes behind the phenomena and as soon as modern science turned to explaining by presenting mathematical descriptions of observed regularities, the "Spirit of Nature" became just an extravagant metaphysical hypothesis. I would now like to turn my attention to Isaac Newton. While he is oft en regarded as a representative of the "new" approach in experimental philosophy (as I have mentioned above), he was still very much concerned with metaphysical matters and in these, similarities can be found between him and More that may throw an interesting light on the possible infl uence of the "Spirit of Nature" on the birth of modern science. But let me fi rst make a couple of tangential remarks concerning the further fate of action through contact. Initially, corpuscularists (just as we saw with Descartes) weren't much open to perceiving action through contact as somehow problematic or needing any further explanation, even more so aft er the publication of Newton's Principia and what some saw as the introduction into physics of forces acting at a distance. For many authors, the only acceptable interpretation of forces acting at a distance was one that reduced them to a series of immediate impulses in a medium linking the point of origin with the point where the force acts. In such a framework, action at a distance is the explanandum and action through contact the explanans that doesn't itself need any further explanation. Later throughout the 18th century, the idea of action at a distance slowly became more and more generally accepted, both among physicists and among philosophers. In this new ideological landscape, the perception of the problem of action through contact changed yet again. First of all, if action at a distance is accepted, there is no reason to problematize action through contact as it can be seen as just a limit case of action at a null distance.27 Th is eventually led to a concep27 Th e other way round, since matter is impenetrable, even when hitting each other, two particles still don't actually share any point of space. Th erefore, even action through contact is ultimately a form of action at a distance (Cf. Immanuel KANT, Metaphysical Foundations of Henry More's "Spirit of Nature" and Newton's Aether 352 tion of matter where the ability to act at a distance was not perceived as a superadded occult quality but rather as one of its intrinsic properties.28 On a more purely metaphysical level, action through contact fades into a much more general problem of causal relationship that becomes more and more popular, proceeding (as we saw) from the question of mind-body interaction in Descartes, through occasionalism up to such philosophers as Hume or the already mentioned Immanuel Kant. Even later on, the whole situation gets further complicated with the introduction of various fi eld theories. Th ese at fi rst sought to postulate some form of material substratum (mostly ether) for themselves, eff ectively reducing action at a distance to material action through contact again. Later, however, they became much more abstract (for Feynman, for example, a fi eld is simply "any physical quantity which takes on diff erent values at diff erent points in space"29). As entities that are in a sense immaterial, they thus ultimately present yet another way of treating action through contact thanks to the fact that they can really be at the exact same place as the aff ected particle.30 To conclude this little detour, let me just add that the problem of action through contact resurfaced in a much diff erent context in the beginning of the 20th century with the advent of quantum mechanics and the related problems of locality and separability31 but these are all subjects that would take us too far from our main focus. Let us then proceed to Isaac Newton. A lot has already been written on possible connections between him and Henry More.32 Th ey certainly must have met during the time they both were at Cambridge. Although Newton read at least some of More's works, explicit mentions of him are absent from his printed works and rather sporadic in the manuscripts (but then again in Natural Science. Cambridge: Cambridge University Press 2004, p. 51 [513]). A modern version of the same argument is analyzed in Marc LANGE, An Introduction to the Philosophy of Physics: Locality, Fields, Energy and Mass. Oxford: Blackwell 2002. 28 See Roger J. BOSCOVICH, A Th eory of Natural Philosophy. Chicago: Open Court Publishing 1922, and more notably KANT, Metaphysical Foundations of Natural Science, for two diff erent attempts at building such a theory of matter. 29 Richard FEYNMAN, Th e Feynman Lectures on Physics Vol II [online]. 1970. Available at: <http://www.feynmanlectures.caltech.edu/II_01.html#Ch1-S2> [retrieved 30. 10. 2016]. 30 For more on this, see Mary B. HESSE, Forces and Fields. Th e Concept of Action at a Distance in the History of Physics. Mineola: Dover 2005, chap. 8. 31 See for example LANGE, An Introduction to the Philosophy of Physics, and Bernard d'ESPAGNAT, On Physics and Philosophy. Princeton: Princeton University Press 2006. 32 Th e classical references are Alexandre KOYRÉ, From the Closed World to the Infi nite Universe. Baltimore: Th e John Hopkins Press 1957, and Edwin A. BURTT, Th e Metaphysical Foundations of Modern Physical Science. London: Kegan Paul 1925. Jacques Joseph 353 general, Newton only rarely quotes or mentions any of his contemporaries). It is generally taken for granted that Newton's conception of absolute space as the sensorium of God is heavily inspired by More's Enchiridion Metaphysicum but otherwise, scholars have been rather careful when trying to trace More's possible infl uences on Newton, especially given the fact that More was not the only Cambridge Platonist and a lot of things Newton might have taken from him, he might just as well have taken from at least several other people, like Isaac Barrow or Ralph Cudworth (not to mention possible shared older, Stoic or Neo-Platonic sources). Especially with this last point in mind, it is not my intention to make any strong claims about links between More and Newton. As I already pointed out, the "Spirit of Nature" is part of a family of notions of a spiritus mundi or pneuma with a tradition ranging back at least to Ancient Neo-Platonists and Stoics. Just like More, Newton was familiar with this tradition and it has already been argued that it had some infl uence on his metaphysical ideas. What I would like to do in this part of my paper is to show a reading of Newton where his attempts at coming up with a cause of gravity are analogical to More's attempts of introducing the "Spirit of Nature", the diff erences being ultimately only ones of emphasis – on mathematical descriptions of regularities amongst phenomena for Newton, and on a coherent metaphysical system as a whole for More. Should this reading be correct, it would allow us to see Newton in a bit of a diff erent light, as well as further highlight the respects in which the "Spirit of Nature" both can and cannot be considered a scientifi c object. From a more historical point of view, it might also serve as at least circumstantial evidence of More's possible infl uence on Newton.33 What cause Newton might have attributed to gravity is one of the most notorious subjects of Newton scholarship and it is not possible for us to fully enter into it. Th e two classical interpretations are that Newton was convinced that gravity had to have a mechanical cause or that its immaterial cause was God.34 One of the loci classici of the debate is Newton's correspondence with 33 It should be noted, in this context, that there is a very close relationship between absolute (divine) space and the "Spirit of Nature" that are both crucial elements of More's (late) philosophical system. See JACOB, More's Manual of Metaphysics 1, p. xxxviff . 34 See e.g. Richard S. WESTFALL, Never at Rest. A Biography of Isaac Newton. Cambridge: Cambridge University Press 1983; Alexandre KOYRÉ, "Gravity an Essential Property of Matter?" In: Alexandre KOYRÉ, Newtonian Studies. London: Chapman & Hall 1965; I. Bernard COHEN, "Newton's Th ird Law and Universal Gravitation." In: SCHEURER, P. B. – DE BROCK, G. (eds.), Newton's Scientifi c and Philosophical Legacy. Dordrecht: Kluwer 1988, pp. 25–53. A good survey of the earlier phase of this debate can be found in John HENRY, "'Pray Do Not Ascribe Th at Notion to Me': God and Newton's Gravity." In: FORCE, J. E. – Henry More's "Spirit of Nature" and Newton's Aether 354 Richard Bentley where Newton repeatedly denies that gravity should be "essential and inherent to Matter".35 In the following letter, Newton elaborates on that subject: It is inconceivable, that inanimate brute Matter should, without the Mediation of something else, which is not material, operate upon, and eff ect other Matter without mutual Contact, as it must be, if Gravitation in the Sense of Epicurus, be essential and inherent in it. And this is one Reason why I desired you would not ascribe innate Gravity to me. Th at Gravity should be innate, inherent and essential to Matter, so that one Body may act upon another at a distance thro' a Vacuum, without the Mediation of any thing else, by and through which their Action and Force be conveyed from one to another, is to me so great an Absurdity, that I believe no Man who has in philosophical Matters a competent Faculty of thinking can ever fall into it. Gravity must be caused by an Agent acting constantly according to certain Laws; but whether this Agent be material or immaterial, I have left to the consideration of my Readers.36 Given the failure of mechanical explanations (a material aether would slow down the course of planets), this passage was oft en taken to mean that the only option left is for there to be an immaterial principle causing gravitational attraction. Now although most scholars have immediately identifi ed this principle as God, the connection does not seem so certain. In one of the more refi ned versions of this argument,37 Betty Jo Teeter Dobbs, using the so-called Classical Scholia, quite convincingly shows infl uences of ancient theories of pneuma and spiritus mundi on Newton's thoughts on the subject of gravity. Th e last step, however, identifying (in Newton's view) this ancient pneuma with the Christian God, still seems unwarranted and based mostly on too literal an understanding of God's omnipresence and of space as His sensorium. Th is idea defi nitely seems at odds with the conception of God's transcendence Newton seems to have held.38 POPKIN, R. H. (eds.), Th e Books of Nature and Scripture. Recent Essays on Natural Philosophy, Th eology, and Biblical Criticism in the Netherlands of Spinoza's Time and the British Isles of Newton's time. Dordrecht: Springer 1994, pp. 123–147. 35 I. Bernard COHEN (ed.), Isaac Newton's Papers & Letters on Natural Philosophy. Cambridge, MA: Harvard University Press 1978, p. 298. 36 COHEN (ed.), Isaac Newton's Papers & Letters, p. 302f. 37 Betty J. T. DOBBS, "Newton's Alchemy and his 'Active Principle' of Gravitation." In: SCHEURER – DE BROCK (eds.), Newton's Scientifi c and Philosophical Legacy, pp. 55–81. 38 Th is is conclusively argued in HENRY, "Pray Do Not Ascribe Th at Notion to Me," p. 132f. Jacques Joseph 355 According to Newton, God is actually present everywhere in the world, yet He certainly doesn't bother with directly causing gravitation or other natural phenomena. For More, this is exactly where the "Spirit of Nature" comes in – a notion, I might add in reference to B. J. T. Dobbs's article, that as we have seen is a direct descendant of the stoic pneuma or Neo-Platonic spiritus mundi. Given the gratuity of the jump from immaterial substance to God himself, the question we should ask is whether all the evidence that Dobbs has gathered doesn't actually point rather in the direction of a spiritual agent similar to the "Spirit of Nature".39 Pursuing this line of thought further, I think we might fi nd it sheds some new light on other related subjects. At this point, it is very important to realize that both the pneuma and the spiritus mundi were entities traditionally considered to have an intermediary status between body and spirit, being in certain respects both, in others neither one nor the other.40 Th is position is still very clearly visible in More's early philosophical poems, where e.g. the "Mundane spirit" is defi ned as "that which is the spirit of the world, or Universe. I mean by it not an Intellectual spirit, but a fi ne unfi xt, attenuate, subtill, ethereall substance, the immediate vehicle of plasticall or sensitive life."41 And although later, as we saw and under the infl uence of Descartes, More opted for a much more radical dualism, the "Spirit of Nature" remains a somewhat problematic entity in that it still bears some residual marks of its original ambiguity. In a similar fashion, we don't necessarily have to see Newton's possible solutions as divided into two radically separate branches (material or immaterial) but rather as complementary attempts at describing, in terms of 17th century dualism, such an intermediate, partly material, partly spiritual concept. As I have already mentioned, any material theory of a gravitational aether had to account for the fact that this aether does not also signifi cantly slow down the planets. Th is seems to be the main problem why Newton renounced a material cause of gravity in the fi rst place, and it is also the reason why, when he came with another take on the aether in the "aether queries" of the 1717 edition of the Opticks, he explicitly defi ned this "new" aether as so extremely rarefi ed that it couldn't possibly aff ect the movement of the plan39 In a diff erent article, though, Dobbs presents a similar argument without this last identifi cation of the pneuma with God (Betty J. T. DOBBS, "Newton's Alchemy and his Th eory of Matter." Isis, vol. 73, 1982, no. 4, pp. 511–528). 40 Th is point is several times emphasized also by Dobbs (DOBBS, "Newton's Alchemy and his Th eory of Matter," p. 523 or 526f.). 41 Henry MORE, Philosophical Poems. Edinburgh: Edinburgh University Press 1878, Interpretation Generall, p. 163. Henry More's "Spirit of Nature" and Newton's Aether 356 ets. He speaks of a medium "700 000 times more elastick than our Air, and above 700 000 times more rare [...]. And so small a resistance would scarce make any sensible alteration in the Motions of the Planets in ten thousand Years."42 To explain this rarity, Newton claimed the particles of aether had to "endeavour to recede from one another."43 Th is is a little awkward as it seems to make the aether itself depend on forces acting at a distance, thus circularly relying on what it was supposed to explain. Steff en Ducheyne pointed out that this aether doesn't necessarily have to be material44 but then the question would be how such an immaterial aether can still be composed of particles. Yet if we accept with B. J. T. Dobbs that Newton's thinking about the cause of gravity grew from traditional aether and pneuma theories and if we fully accept that these traditional conceptions defi ed strictly dualistic categorization, we may take the Opticks aether to be yet another attempt of describing such an ambiguous concept in scientifi c terms. In this context, it should also be noted that traditional descriptions of this intermediary aether make use of the same metaphor (though less "mathematized") – the aether is a spirit, yet so gross it is almost a body; and a body but one so subtle and so rare, it is almost a spirit.45 Such an understanding would also help make a much closer link between Newton's "mechanistically inspired" material aether and the aether of his earlier, alchemical works. It is by now generally accepted that Newton's alchemical studies were the source of a lot of his later ideas in physics but a huge discontinuity is perceived between the alchemical aether and that of the Opticks.46 Although it is true that the aether of Th e Vegetation of Metals is not described as composed of particles endowed with repulsive forces, Newton does say it is "by many degrees more thin & rare then air"47 and he also connects it to the same phenomena as in the Opticks (light, heat, magnetism but also vegetative life!). Th is alchemical aether is also described as 42 Isaac NEWTON, Optics. Mineola: Dover 1952, p. 352f. 43 Ibid. 44 Steff en DUCHEYNE, "Newton on Action at a Distance and the Cause of Gravity." Studies in History and Philosophy of Science Part A, vol. 42, 2011, no. 1, pp. 154–159. 45 Cf. Eric R. DODDS – PROCLUS, Th e Elements of Th eology. Oxford: Clarendon Press 1963, p. 315. 46 See for example John HENRY, "Gravity and De Gravitatione: Th e Development of Newton's Ideas on Action at a Distance." Studies in History and Philosophy of Science Part A, vol. 42, 2011, no. 1, pp. 11–27. 47 Isaac NEWTON, Th e Vegetation of Metals. Dibner Collection, Smithsonian, MS 1031 B, 3v [online]. 1674?. Available at: <http://webapp1.dlib.indiana.edu/newton/mss/norm/ ALCH00081> [retrieved 7. 11. 2016]. Jacques Joseph 357 "the material soule of all matter" or "a vehicle to some more active spirit,"48 quite clearly demonstrating its intermediate corporeo-spiritual character. All these, as many other expressions found in the manuscript, could also have been taken straight from any of More's early works – or from other Cambridge Platonists', for that matter. Th e point, here again, is not to claim any direct infl uence of More on Newton, but rather to open up a new point of view on Newton's aether through showing the functional similarities between it and More's "Spirit of Nature". Besides these similarities, however, there are also diff erences; diff erences that again relate to the shift from natural to experimental philosophy. More's primary concern was metaphysics while Newton, though also obviously concerned with such matters, tried to keep them away from his more mathematical and physical research. In this sense, the law of gravitation was more important for Newton than any metaphysical principle we may try to put behind it. And without trying to reduce the importance of the metaphysical and alchemical part of Newton's thinking, without – as has so oft en been done – trying to make Newton into "the fi rst positivist", it seems quite clear this shift of focus was at least in part due to the fact that he considered these mathematical questions more fi t objects of scientifi c research. At the same time, Newton obviously looked for an (at least partially) immaterial cause of gravity and while I agree with Dobbs that this immaterial cause drew on traditional conceptions of pneuma and spiritus mundi (possibly at least partially mediated by Henry More), I do not think however that Newton identifi ed this cause with God. What, then, would this immaterial agent be? For More, it was an omnipresent and blindly programmed "Spirit of Nature". For Newton, it might have been something similar, or possibly a not completely material aether, as the one described in the Opticks. Th rough all their superfi cial diff erences, all these options would be (on our reading) just diff erent attempts at adapting the traditional conception of a pneuma or spiritus mundi to the framework of the new physics. Conclusion While it doesn't seem obvious from the point of view of contemporary science, animistic and spiritual notions had for a long time a strong infl uence on the problems of action at a distance49 and in a way, this article may be 48 Ibid., p. 4r. 49 See HESSE, Forces and Fields. Henry More's "Spirit of Nature" and Newton's Aether 358 considered a more detailed case study of one such example. We have seen Henry More's "Spirit of Nature" as a late fruit of a tradition of notions of spiritus mundi used within an early modern context as an explanation for various seemingly non-mechanical phenomena. I have tried to show, on the one hand, in which respects it may be considered a scientifi c notion and, on the other hand, in which respects it may not. Of course, these considerations depend a lot on our expectations of what science ought to do and, during More's lifetime, these expectations were undergoing quite a radical change. Th e "Spirit of Nature" thus worked as a scientifi c object in that it provided an explanation of the metaphysical workings behind various phenomena (mechanical or not). Most notably, it "explained" action through contact, thus eff ectively providing the grounding underlying any mechanical explanation at all. Yet it never had the possibility of fully entering the discourse of science, because it is exactly this connection with metaphysics that later science tried to sever under the famous motto "hypotheses non fi ngo". Funnily enough, for Newton himself, though he was very careful about "framing hypotheses", metaphysical concerns, though not part of the mathematical treatment of the given questions, were still very important. A comparison between More's "Spirit of Nature" and Newton's inquiries into the cause of gravity seems to vindicate B. J. T. Dobbs's claim that Newton drew from theories of pneuma or spiritus mundi. Furthermore, we should keep in mind that this concept was traditionally one of an intermediate substance between matter and spirit – the traces of which ambiguity can, in my opinion, be traced both in More and Newton, even though both seem to work in a more or less dualistic framework. Under this perspective, Newton's various attempts at providing a metaphysical explanation of the cause of gravity are ultimately only attempts to fi t this intermediate concept into the new science. In this sense, these attempts are similar to what More tried to do with his "Spirit of Nature", although both the specifi c ways of accommodating the given concept and what either author perceived to be what ultimately matters are diff erent. Th ese similarities and diff erences allows us to see how close and at the same time distant More and Newton were and, regardless of any possible direct infl uence of More on Newton, they also let us appreciate how "spiritual successors" to the "Spirit of Nature" helped shape the face of modern science. Jacques Joseph