Peter Anstey writes…
Antoine Le Grand (1629–1699) was probably the most important Cartesian philosopher living in England in the latter decades of the seventeenth century. A Franciscan who was domiciled in England from 1656 until his death, he published a series of Latin works in the 1670s defending Descartes’ philosophy using the traditional approach of arguing from first (Cartesian) principles. The books include:
- Institutio philosophiae, London, 1672 (2nd edn 1680)
- Historia naturae, London, 1673 (2nd edn 1680)
- Dissertatio de carentia sensus & cognitionis in brutis, London, 1675.
Updated versions of these three books were subsequently brought together in an English translation that appeared in 1694 under the title An Entire Body of Philosophy According to the Principles of the Famous Renate Des Cartes, published by the entrepreneur Richard Blome. The title is apt because Le Grand’s magnum opus does indeed present a complete Cartesian philosophy, including metaphysics, logic, natural philosophy, and ethics.
Two of his works are of particular interest to students of early modern experimental philosophy. The first is his Historia naturae, variis experimentis & ratiociniis elucidata secundum principia stabilita in Institutione Philosophiae (The history of nature elucidated by various experiments and reasoning, according to the principles established in Institutes of [Cartesian] Philosophy). The first 1673 edition of this work was dedicated to Robert Boyle who is described in the dedication as a promoter of experimental philosophy [experimentis Philosophia]. The second 1680 edition is not dedicated to Boyle, but mentions the illustrious Bacon in its dedication to John Lumley.
One might expect, therefore, that Le Grand’s book will take the form of a Baconian natural history, after the manner of Boyle’s own natural histories. Yet what Le Grand presents is structured in a similar way to an Aristotelian textbook of natural philosophy but one founded upon Cartesian natural philosophical principles. The salient feature, however, is that it includes copious references to experiments that others have performed, all of them brought to the task of establishing the truth of Le Grand’s form of Cartesianism: ‘my intention in this work …. is to show that all the phenomena we observe throughout [nature] conform well to the principles in [my] Institutes of Philosophy‘ (Historia naturae, 1673, Preface). Le Grand’s Historia naturae then, can hardly be described as a contribution to the natural historical program of the experimental philosophers. It is to my knowledge, however, the earliest Cartesian natural history written in the wake of the emergence of experimental philosophy.
The second book of interest is Le Grand’s compilation, An Entire Body of Philosophy According to the Principles of the Famous Renate Des Cartes. The first part, the Institution of Philosophy, contains ten sub-parts. The last three sub-parts concern the nature of humans: the human body, the human mind, and ethics. When we drill down to the final chapter of the sub-part that pertains to the human body, we find that it concerns the nature and use of medicines.
This chapter is of singular interest because it contains a long discussion of specific medicines, that is, those remedies that were thought by some physicians to be especially efficacious in the cure of particular diseases. It turns out, however, that this long discussion of specifics is a plagiarised summary of the first dissertation of Boyle’s book On the Reconcileableness of Specific Medicines to the Corpuscular Philosophy (1685). Worse still, the publisher Richard Blome, claims on the title page that the whole book has been translated from the Latin originals, including ‘large Additions of the Author, never yet Published’. However, there is irrefutable evidence that the plagiarised material from Boyle’s Specific Medicines was taken directly from the original English edition, i.e. none of this material derives from a Latin original. So, what Le Grand has to say about specifics is exactly what Boyle said about them, sometimes word-for-word! Whether Le Grand is responsible for this or it is a presumptuous addition written or sanctioned by Blome is unknown, though the interweaving of the paraphrases with verbatim quotes from Boyle suggests that it does not derive from Le Grand himself who preferred to write in French and Latin.
Nevertheless, there are two important features of this act of plagiarism that pertain to speculative philosophy. First, where Boyle used the corpuscular hypothesis to explain the mode of operation of specific medicines, Le Grand appropriates Boyle’s corpuscular explanations in the defence of Cartesianism. Here we have a very good example of the compatibility of corpuscularianism and Cartesianism that Boyle highlighted in his early expositions of the speculative corpuscular hypothesis. (See Boyle’s Certain Physiological Essays, Works of Robert Boyle, eds Hunter and Davis, London, 1999–2000, 2: 87.)
Second, in spite Le Grand’s appropriation of some of the experimental evidence cited in Boyle’s book, it should not be thought that we have here a Cartesian doing experimental philosophy. For Boyle is explicit in a number of places in Specific Medicines that he is writing a speculative work providing speculative corpuscular explanations of the operation of specifics: ‘the ensuing discourse is for the main of a Speculative nature’ (ibid., 10: 353). Le Grand is doing the same. In fact, this characterises much of Le Grand’s use of experimental observations in the rest of his Entire Body of Philosophy: experimental evidence is not considered in its own right but is almost always brought to the aid of his defence of Cartesianism.
For example, like Jacques Rohault, he argues that the Torricelian experiment does not provide evidence for the existence of a vacuum because the glass tube has pores ‘which are penetratrable by the Subtil matter’ (An Entire Body of Philosophy, Part II, 6 = Historia naturae, 1673, 15). This use of experimental evidence is precisely what experimental philosophers opposed and the reason why Boyle was quite clear that he was indulging in speculation in Specific Medicines. In this Le Grand resembles some of the Cartesians in France; he was well apprised of the fruit of the new experimental philosophy of his day, but rather than contributing to it, he appropriated it in defense of Cartesianism.
If any readers know of other Cartesian natural histories from the 1670s I would be very keen to hear from you.
Peter Anstey writes …
There were many critics of experimental philosophy in its early years. On this blog we have discussed the criticisms of Margaret Cavendish and Francis Bampfield, both of whom were English, and G. W. Leibniz, who was German. In this post we examine the views of the French philosopher Nicolas Malebranche who was highly critical of experimental philosophy too.
In the first edition of his The Search After Truth of 1674, Malebranche devotes the last section of Book Two to ‘Those who perform experiments’, and this section appears in all six subsequent editions of the book. (See The Search After Truth, eds T. M. Lennon and P. J. Olscamp, Cambridge: Cambridge University Press, 1997, pp. 159–60.)
He opens his treatment of the subject with some general comments that apply both to chemists and ‘all those who spend their time performing experiments’. Ostensibly, the criticisms are not directed at experimental philosophy per se, but towards experimental philosophers themselves. ‘Do not blame experimental philosophy [philosophie expérimentale]’, says Malebranche; it is the errors of its practitioners that he castigates.
He then proceeds to list seven faults, though ‘there are still many other defects … we do not pretend to cover them all here’ (p. 160).
First, their experiments are normally directed by chance and not by reason.
Second, they are ‘preoccupied with curious and unusual experiments’ rather than beginning with the simplest and building up from there.
Third, they seek out those experiments that will bring them profit, lucriferous experiments, as Bacon would call them.
Fourth, they don’t take enough care to note down ‘all the particular circumstances’ that pertain to the experiment at hand, the time of day, place, quality of the materials, etc.
Fifth, they draw too many conclusions from a single experiment, whereas it’s normally the case that one conclusion can only be drawn from many experiments.
Sixth, they only consider particular effects without ascending to ‘primary notions of things that compose bodies’ (p. 159).
And seventh, they often ‘lack courage and endurance, and give up because of fatigue or expense’ (p. 160).
None of these criticisms seem very serious, after all, it is easy to find exceptions to each one in the experimental practice of experimental philosophers in the 1660s and 1670s. One could hardly accuse Newton’s of being directed by chance in the construction of his experimentum crucis for establishing the heterogeneity of white light, even if his discovery of the oblong form of the spectrum of colours in his first experiment was unexpected or discovered by chance. Nor could one accuse Boyle of giving up on account of fatigue or expense in his air-pump experiments.
Yet the heart of Malebranche’s critique is found in the final paragraph of the section on the causes of the seven defects. He lists three causes: lack of application, misuse of the imagination, and, most importantly, judging the differences and changes among bodies only by sensation (p. 160).
This third cause is Malebranche’s real reservation about, not experimental philosophers, but experimental philosophy itself: for this cause implies an over-reliance on the senses, and by implication, an under-utilisation of reason, and, in particular, reasoning from clear and distinct ideas. The whole of Book One of The Search After Truth is given over to a discussion of the unreliability of the senses. For example, one rule of thumb that he sets out in Chapter 5 is: ‘Never judge by means of the senses as to what things are in themselves …’ (p. 24).
Of course, Malebranche is not averse to appealing to experiments and observations when they reinforce a point he is making (see Book I, chap. 12, pp. 56–7), however, the prioritising of experiment and observation above reasoning from pre-established principles and hypotheses – a central tenet of experimental philosophy – is not one of his epistemic values. Malebranche was opposed to experimental philosophy in principle, and not merely because of the ‘defects’ of its practitioners.
Alberto Vanzo and Peter Anstey are pleased to announce the publication of Experiment, Speculation and Religion in Early Modern Philosophy, New York: Routledge, 2019.
This is the first collection ever published that is dedicated to the theme of early modern experimental philosophy. It contains studies of individual philosophers –– Bacon, Boyle, Cavendish, Hobbes, Locke and Newton –– as well as studies of the place of hypotheses, the relation between experimental philosophy and religion and a critical overview of the state of the field in contemporary scholarship.
Alberto vanzo and Peter R. Anstey
- Francis Bacon on Sophists, Poets and other Forms of Self-Deceit (Or, What can the
Experimental Philosopher Learn from a Theoretically Informed History of Philosophy?)
- Robert Boyle and the Intelligibility of the Corpuscular Philosophy
Peter R. Anstey
- Cavendish and Boyle on Colour and Experimental Philosophy
- Appeals to Experience in Hobbes’ Science of Politics
- Locke and the Experimental Philosophy of the Human Mind
- Newton’s Scaffolding: The Instrumental Roles of his Optical Hypotheses
- What (Else) was Behind the Newtonian Rejection of ‘Hypotheses’?
- From Experimental Natural Philosophy to Natural Religion: Action and Contemplation in the Early Royal Society
- Experimental Philosophy and Religion in Seventeenth-Century Italy
- Early Modern Experimental Philosophy: A Non-Anglocentric Overview
Peter Anstey writes…
Until now the earliest evidence for Locke making Boyle’s acquaintance is a letter from Dr Ayliffe Ivye to Locke of 20 May 1660. This letter implies that Locke knew Boyle by this time and Ivye recommends to Locke that he ‘lett slippe no occasion’ to develop his acquaintance with Boyle (Locke Correspondence, ed. E. S. de Beer, vol. 1, p. 146). New evidence has now emerged that strongly suggests that Locke knew Boyle at least two years earlier, in 1658.
Locke’s earliest surviving medical notebook, Bodleian Library MS Locke e. 4, was in use in the 1650s. There appears to be no indication from its contents that Locke used it after 1658. In this notebook there are a number of entries deriving from a person called M. B. Could this refer to M[r] B[oyle]? The content of one of these entries confirms that it does.
On page 59 Locke made the following entry under the marginal title ‘Obstructio’:
A lady that had been sick a great while of the * & used very much physic to noe purpose was curd presently by useing her owne water M. B.
Locke almost certainly heard this from Boyle, because in Usefulness of Experimental Natural Philosophy (1663), which he was composing in the late 1650s, Boyle relates:
I knew an ancient Gentlewoman, who being almost hopeless to recover of divers Chronical Distempers (and some too of these abstruse enough) was at length advised, instead of more costly Physick, to make her Morning-draughts of her own Water; by the use of which she strangely recovered, and is, for ought I know, still well. (Boyle Works, eds Hunter & Davis, vol. 3, p. 385)
It is unlikely that this entry was made before 1658 because in this notebook, apart from some very early entries at the end, Locke seems to have made entries in chronological order and ‘Obstructio’ is preceded by references to Marin Cureau de la Chambre’s A Discourse on the Principles of Chiromancy (London, 1658) on pages 25–6.
There is an entry derived from M. B. that precedes the one quoted above (MS Locke e. 4, p. 43), it occurs after the entry from de la Chambre. So, there are no grounds on the basis of this notebook for claiming that Locke had met Boyle before 1658.
What all of this shows is that Locke met Boyle at the very time when the latter was formulating his new approach to natural philosophy that he came to call experimental philosophy.
A guest post by Kenny Pearce.
Kenny Pearce writes …
It is by now well-known that Locke intentionally sets his Essay in the context of Baconian natural history, the project of the Royal Society. This can be seen in Locke’s mention of several prominent members of the Society in the Epistle to the Reader, and his description of his own role as that of an “Under-Labourer … removing some of the Rubbish, that lies in the way of Knowledge” (Essay, Nidditch p. 10). It can also be seen in Locke’s explicit description of his project as following the “Historical, plain Method” (§1.1.2), and in his assertion to Stillingfleet that “if [his ‘way of ideas’] be new, it is but a new history of an old thing [i.e., human understanding]” (Works, 4: 134–135). Further, it is clear that the Essay was received as a contribution to Baconian natural history in the decades following its publication. For instance, in a footnote to his 1732 translation of William King’s Essay on the Origin of Evil, Edmund Law refers to the Essay concerning Human Understanding as “Mr. Locke’s excellent History of the human mind” (vol. 2, p. 308), and in his 1734 Philosophical Letters, Voltaire writes, “After so many thinkers had written the romance of the soul, there came a wise man [Locke] who modestly described its history” (Steiner p. 42).
But what exactly is this Baconian project, and what bearing should it have on our reading of Locke’s Essay? Thomas Sprat, the earliest historian of the Royal Society, describes its methods as follows:
The Society has reduc’d its principal observations, into one common-stock; and laid them up in publique Registers, to be nakedly transmitted to the next Generation of Men; and so from them, to their Successors. And as their purpose was, to heap up a mixt Mass of Experiments, without digesting them into any perfect model: so to this end they confin’d themselves to no order of subjects; and whatever they have recorded they have done it, not as compleat Schemes of opinions, but as bare unfinish’d Histories … For it is certain, that a too sudden striving to reduce the Sciences, in their first beginnings, into Method, and Shape, and Beauty; has very much retarded their increase … By their fair, and equal, and submissive way of Registring nothing, but Histories, and Relations; they have left room for others, that shall succeed, to change, to augment, to approve, to contradict them, at their discretion (Sprat, The History of the Royal-Society , pp. 115–116).
According to Sprat, the key to the method of natural history is to “heap up a mixt Mass of Experiments” and observations (or ‘instances’ as Bacon liked to call them) without working them into a system. This is important because it will allow future generations of natural philosophers “to change, to augment, to approve, to contradict” the conclusions drawn by those who made the observations.
Law and Voltaire were, I believe, perfectly correct in regarding Locke’s Essay as a natural history of the human understanding, working within the Baconian methodological paradigm. This is not merely supported by Locke’s occasional uses of the words ‘history’ and ‘historical’, quoted above. It is also supported by Locke’s explicit descriptions of his methodology. For instance:
This, therefore, being my Purpose to enquire into the Original, Certainty, and Extent of humane knowledge; together, with the Grounds and Degrees of Belief, Opinion, and Assent; I shall not at present meddle with the Physical Consideration of the Mind; or trouble my self to examine, wherein its Essence consists, or by what Motions of our Spirits, or Alterations of our Bodies, we come to have any Sensation by our Organs, or any Ideas in our Understandings; and whether those Ideas do in their Formation, any, or all of them, depend on Matter, or no (Essay 1.1.2).
for [my account of the origin of ideas] I shall appeal to every one’s own observation and experience (Essay 2.1.1)
my design being, as well as I could, to copy nature, and to give an account of the operations of the mind in thinking, I could look into nobody’s understanding but my own, to see how it wrought … All therefore that I can say of my book is, that it is a copy of my own mind, in its several ways of operation. And all that I can say for the publishing of it is, that I think the intellectual faculties are made, and operate alike in most men (Works, 4: 138–139).
Further, in the actual text of the Essay, Locke does indeed appear to follow this method: he aims to describe, in an orderly fashion, the phenomena revealed by introspection. The case against innate knowledge and innate ideas in book one focuses primarily on arguing that no example of an innate idea or item of innate knowledge has yet been produced: there is no true specimen of such a thing in our register. Book two is then a detailed catalogue or register of ideas, and book four is a catalogue of instances of assent (knowledge and belief). (Book three, on language, was apparently an afterthought, not fitting neatly into the ‘method’ Locke originally proposed; see Essay 2.23.19.)
This line of interpretation has consequences for how we must understand Locke’s account of ideas. If Locke is following this kind of Baconian methodology then, although he does at various points seek to explain various phenomena, his ‘ideas’ cannot be understood as theoretical posits aiming to explain how we perceive external objects. Locke makes no attempt to explain “by what Motions of our Spirits, or Alterations of our Bodies, we come to have any Sensation by our Organs, or any Ideas in our Understandings” (Essay 1.1.2), and frequently admits that, although we can give mechanical explanations of the transmission of information from objects to the brain, the mind-brain interface remains utterly mysterious. Instead of attempting to solve this mystery, Locke aims simply to describe the ideas of which we are aware.
If this is correct, then, although there is a sense in which the Essay is a systematic treatment of the human mind, there is another sense in which Locke is an intentionally, self-consciously unsystematic thinker and the Essay is an intentionally unsystematic work. The Essay, as a natural history of the human understanding, is systematic in that Locke’s observations and the generalizations he draws from them are laid out in a reasonably orderly fashion, intending to be of use to future natural historians. But it also exhibits a Baconian skepticism about ‘grand systems’. The human understanding, Locke has observed, is (like most natural phenomena) messy and complex and, in Locke’s view, it would be a serious methodological error to try to massage this messiness out of the data. A neat and clean, elegant and systematic account of the human understanding would be a ‘romance’ and not a modest history.
(This post is based on a portion of a paper in progress, “Ideas and Explanation in Early Modern Philosophy.” You can read a draft here. Many thanks to Kirsten Walsh for the invitation to share these thoughts in this forum. Comments welcome below!)
Locke Studies makes Vols 14–16 freely accessible online
We are pleased to announce that Vols 8, 9 and 14–16 of Locke Studies are now freely available on the Locke Studies website<https://protect-au.mimecast.com/s/XhIpCD1jy9tMoolwflPWVy?domain=thejohnlockesociety.us15.list-manage.com>. The editorial team of the journal will continue to add back issues to the website as quickly as they are able to prepare them. Eventually the entire series of Locke Studies and The Locke Newsletter will be digitized and freely available. Hyperlinks to each article will be added to the entries in the Locke Bibliography<https://protect-au.mimecast.com/s/xX-0CE8kz9tnll5OiQruGS?domain=thejohnlockesociety.us15.list-manage.com> as they are published online.
Visit the Locke Studies Archive<https://protect-au.mimecast.com/s/k-TvCGvmB5iqBB5Ef1kf2t?domain=thejohnlockesociety.us15.list-manage.com>
2017 Issue of Locke Studies
The table of contents is available via the website, but the PDFs of the articles will not be made available until Jan 2019. Beginning with the 2018 issue, all new content will be open access immediately upon publication. Here is the table of contents for the 2017 issue of Locke Studies:
Recent Publications, pp. 5–38
JOHN C. ATTIG
Locke’s Orthography and the Dating of his Writings, pp. 39–47
J. R. MILTON
A Puzzle in the Print History of Locke’s Essay, pp. 49–60
PATRICK J. CONNOLLY
Locke’s Ontology of Relations, pp. 61–86
SAMUEL C. RICKLESS
Locke on Individuation and Kinds, pp. 87–116
Toland and Locke in the Leibniz-Burnett Correspondence, pp. 117–141
Shaftesbury, Locke, and their Revolutionary Letter?, pp. 143–171
D. N. DELUNA
Locke and Hate Speech Law: A Critical Review, pp. 173–196
J. K. NUMAO
Locke’s Political Theology and the ‘Second Treatise’, pp. 197–232
Locke and the Churchill Catalogue Revisited, pp. 233–241
JOHN SAMUEL HARPHAM
Peter Anstey writes…
Sometimes we can appreciate the impact of a new way of thinking or a new movement by examining the views and writings of those on the periphery or of minor, lesser-known figures. Such is the case with the Scotsman Martin Martin. His A Description of the Western Islands of Scotland published in 1703 is written as a Baconian natural history, and in its short preface Martin very self-consciously situates his work as a contribution to experimental philosophy.
It is well known that the book gained some renown in the eighteenth century for its discussion of the phenomenon of second sight –– a discussion that is literally matter of fact and which accords with the methodology of experimental philosophy in so far as he refrains from entertaining any speculations concerning causes of this phenomenon.
The book also gained some notoriety from the fact that Boswell and Johnson used it as a kind of travel guide for their tour of the western Scottish isles in 1773. Yet it is Martin’s brief but poignant methodological comments that are of interest to students of early modern experimental philosophy.
Martin views his book as something of a supplement to the leading histories of Scotland, especially that of George Buchanan, whose History of Scotland (Rerum Scoticarum historia, Edinburgh) appeared back in 1582. Martin tells us:
since his [Buchanan’s] time, there’s a great Change in the Humour of the World, and by consequence in the way of Writing. Natural and Experimental Philosophy has been much improv’d since his days, and therefore Descriptions of Countries without the Natural History of ’em, are now justly reckon’d to be defective. (sig. a4r)
This comment signals Martin’s understanding of the place of natural history in the methodology of experimental philosophy and the requirement that histories of countries have a natural historical component. He goes on to list some of the topics that he covers in order to render his account of the western isles of Scotland such a natural history:
the Nature of the Climate and Soil, of the Produce of the Places by Sea and Land, and of the Remarkable Cures perform’d by the Natives meerly by the use of Simples, and that in such variety as I hope will make amends for what Defects may be found in my Stile and way of Writing. (sig. a5v)
These topics or heads or articles of inquiry are typical of this genre of natural history, and much of the actual content of the book covers Robert Boyle’s desiderata for the natural history of a country set out as early as 1666 (‘General Heads for a Natural History of a Country, Great or Small’) in the Philosophical Transactions (vol. 1, pp. 86–9) and republished in 1692.
Martin mentions experimental philosophy a second time:
Humane Industry has of late advanc’d useful and experimental Philosophy very much, Women and illiterate Persons have in some measure contributed to it by the discovery of some useful Cures. (sig. a5v–a6r)
Now, from a 21st century perspective the comment on women and the illiterate might seem condescending, nevertheless, Martin’s is making the very Baconian point that not just the learned, but everyone can contribute to the project of the history of nature. He then goes on to stress the importance of observation:
the Field of Nature is large, and much of it wants still to be cultivated by an ingenious and discreet application; and the Curious by their Observations might daily make further advances in the History of Nature. (sig. a6r)
It is worth noting that the inspiration for his natural history derived from some within the Royal Society itself, probably including Hans Sloane. For, we are told in the Preface to his earlier A Late Voyage to St. Kilda, London, 1698 (dedicated to the then President of the Royal Society, Charles Montagu), that he had had the
honour of Conversing with some of the Royal Society, who raised his natural Curiosity to survey the Isles of Scotland more exactly than any other; in prosecution of which design he as already brought along with him several curious Productions of Nature, both rare and beautiful in their kind (sig. A4v)
It might be thought, therefore, that Martin’s text is one of many such natural histories from the early eighteenth century; however, I have argued elsewhere that from the 1690s this approach to experimental philosophy actually began to decline. Not only had the program of experimental natural history not delivered much by way of new natural philosophy, but also a rival mathematical form of experimental philosophy was emerging in the wake of Newton’s Principia (1687). If this thesis concerning the decline of Baconian natural history is correct, Martin’s work should be viewed as one of the final installments of an approach to experimental philosophy that was soon to be superseded, even if it never completely disappeared.
Moreover, Martin seems to have had few like-minded natural historians around him in Scotland. Andrew Fletcher of Saltoun, Scotland wrote to John Locke in October 1701 and had the letter hand delivered by Martin. Fletcher recommends him to Locke and, after mentioning Martin’s materials for his natural history of ‘westerne isles of Scotland’ says,
Their is so little encouragement for such a man herre, that if he can meete with any in England, he thincks of staying their or going further abroad (Correspondence of John Locke, Oxford, vol. 7, p. 471)
I would be most interested in hearing from readers about other examples of Baconian natural histories in Britain in the early years of the eighteenth century that might complement that of Martin Martin and round out my own understanding of this very fascinating manifestation of experimental natural philosophy.
A second guest post by Hanna Szabelska.
Hanna Szabelska writes …
As I indicated in my previous post, the fatal destiny (fatalité), about which Voltaire complained in a letter to Jean-Jacques d’Ortous de Mairan , made Madame du Châtelet’s mind more and more prone to the allure of Leibniz’s metaphysics, in particular his concept of vis viva.
For example, the comparison of fire to living force notwithstanding, the first edition of her essay on heat shows the traces of the influence of de Mairan’s Dissertation sur l’estimation et la mesure des forces motrices des corps. One possible reason for this inconsistency being that de Mairan distanced himself from metaphysics and concentrated on pure laws of motion . In the version submitted for the Academy’s prize competition, du Châtelet added a note criticising Leibniz and praising de Mairan as an advocate of the Cartesian measure of force (mv). Afterwards the Marquise desperately fought for permission to remove it before publication. She argued that this insipid compliment (fadeur) had resulted from her ignorance and was not related to the main theme. But she was unsuccessful .
The Leibnizian measure – mv² – was incorporated only in the second version together with a remarkable passage that unravels a complex interplay between the experimental and the speculative approach in du Châtelet. Having discussed the hypothesis that the Sun is a solid body containing fire and emanating it to the Earth, she concludes:
But this emanation of light is subject to far greater difficulties, and seems impossible to be assumed despite the modern observations that apparently speak in its favour: certain observations are enough to destroy a superstition when they seem contrary to it, but they are not enough to establish it and physical and metaphysical difficulties undermining the [hypothesis of] emanation of light seem so insuperable that without them being removed there are no observations that can induce one to assume it. But this is not the place to discuss them. 
The moral of this digression is that observational data are not enough to establish a hypothesis if there are strong metaphysical objections against it. This is the assumption, although not always articulated, that remains at the core of du Châtelet’s rhetorical vein in the heat of debates, e.g. her discussion with de Mairan about one of Jacob Hermann’s experiments and the measure of force. Remarkably, the exchange with de Mairan was published not only together with the Institutions physiques (1742), the second edition of du Châtelet’s manual of physics, but also with the revised version of her essay on fire.
The experiment in question is as follows :
Let the ball A move with the velocity 2 on a horizontal plane and collide with another ball B=3A, being at rest. The ball A will give the velocity 1 to the ball B and move backwards with the velocity 1. Afterwards, let the ball A with the velocity 1 collide with another body at rest C=A. The ball A will also give to the ball C the velocity 1 and as a result of the second collision, it will come to halt. All this can be easily derived from the very well known rules of the motion of elastic bodies. 
To disprove du Châtelet, de Mairan adds scalar magnitudes (m|v|), and then he goes on to directed ones, i.e. applies the measure he accepted. 
His calculation could be interpreted as a correct addition of momenta , but du Châtelet does not consider it either as an alternative of force measure or a different concept. Here comes into play her rhetorical impetus:
To tell the truth, it is remarkable with what ease this small bar you put in front of the formula for the force of the body A rid you of this 8 of force that even your own calculation gave you after collision instead of 4 that you had expected from it; but, tell me, I beg you, you certainly do not think that this sign minus and this subtraction would take away some part of force from the bodies A and B, and that the effects exercised by these bodies on any obstacles would be diminished by it. I also doubt that you would like to either experience it or find yourself in the path of a body that would bounce back affected by this minus sign with 500 or 1000 of force. 
One may think that du Châtelet did not understand the concept of directed magnitudes but was this really the case? After all, she was a very attentive reader of Willem Jacob ‘s Gravesande, who analyses the paradoxical cases of bodies moving in the opposite directions and compares the effectiveness of Leibnizian force measure with the Cartesian one.
This is the description of ‘s Gravesande’s experiment, somewhat simplified by du Châtelet: 
‘s Gravesande devised an experiment that wonderfully confirms this theory. He fastened a ball of clay in Mariotte’s Machine and he made it collide successively with a copper ball, whose mass was three and velocity one, and with another ball of the same metal, whose velocity was three and mass one, and it happened that the impression made by ball one, whose velocity was three, was always much greater than that made by ball three with the velocity of 1, which testifies to the inequality of the forces. But when these two balls with the same velocities as before collided at the same time with the clay ball freely suspended from a thread, the clay ball was not shaken and the two copper balls stayed at rest and equally sunk in the clay and after measurement these equal impressions were found to be much greater than the impression that ball three with the velocity of one had made, having hit only the fastened clay ball and less than that which had been made by ball 1 with the velocity three. For ball 3 consumed its force to make an impression on clay, and its impression having been augmented by the effort of ball one that pressed the clay ball against ball three, reduced the impression of this ball one. Therefore, soft bodies that collide with velocities in inverse proportion to their masses, stay at rest after the collision, because they consume all their forces to mutually impress their parts. For it is not simple rest that holds these parts together, but a real force, and in order to flatten a body and drive into its parts, this force, named coherence or cohesion, must be overcome, and nothing but the force used to drive into these parts is consumed in the collision. 
For both ‘s Gravesande and du Châtelet force is a positive magnitude . Besides, she obviously agrees with ‘s Gravesande that opposite forces do not destroy each other in a direct manner but their interaction is much more complicated: in the collision of two bodies whose forces are opposite there are two actions and two reactions. 
But there is one crucial difference between them: ‘s Gravesande, a Newtonian converted to the Leibnizian force measure by his experiments, was particularly sensitive to difficulties involved in theorizing observational data. For him, the concept of force is vague and leaves room for alternative measurements:
If the word ‘force’ is given a different meaning, if this different meaning is said to be more natural, I do not object: all I wanted to claim is that this what I have called ‘force’ must be measured by the product of mass and velocity squared. In order to claim that it is possible to assume a different measure of force as considered under a different aspect it is necessary to explain all the experiments conducted with respect to force and collision. This is what we do on our part; and I assure you that this has not been done yet by those who have adopted the contrary opinion. 
Not so Madame du Châtelet. The Marquise’s irony towards de Mairan, sardonic despite her capacity to grasp counterarguments, tempts one to suppose that it is one of the aforementioned difficultés métaphysiques that underlies it. Should the Cartesian force be posited as a metaphysical principle of the Universe, the Universe could potentially be left with a metaphysically embarrassing zero value (like in the case of two moving bodies whose momenta are equal but opposite: p and –p). In this respect, velocity squared in the vis viva formula guarantees its superiority.
What follows from this is that the relationship between the speculative and the experimental in du Châtelet’s arguments is far from being straightforward. On the one hand, rigorous conceptualization of experiments like that of Boerhaave can serve to build up metaphysical principles, e.g. weightless fire as one of the springs of the Creator. On the other, there is sometimes hidden metaphysical bias in interpreting experiments as the example of Hermann’s balls proves. This complex mix is certainly incommensurable with mathematized classical mechanics as taught today. The question that imposes itself here is: are we really able to pin down the slippery Proteus of experimentalism with a Leibnizian tinge?
- MLXXXIV – A M. de Mairan, à Bruxelles, le 1er avril 1741, in Oeuvres complètes de Voltaire, ed. Ch. Lahure, vol. 25 [Paris: Librairie de L. Hachette, 1861], p. 522.
- de Mairan, Dissertation sur l’estimation et la mesure des forces motrices des corps, Nouvelle édition, ed. Deidier [Paris, 1741], pp. 7-8.
- Mary Terrall, “Vis viva Revisited,” History of Science 42 (2004): 189-209.
- cf. Letter 148. To Pierre Louis Moreau de Maupertuis, Les lettres de la Marquise du Châtelet, ed. Theodore Besterman [Genève: Institut et Musée Voltaire, 1958], vol. 1, pp. 266-267; the errata allowed by the Academy contains nothing but a stylistic improvement; note a factual mistake in Du Châtelet, Selected Philosophical and Scientific Writings, ed. Judith P. Zinsser [Chicago: University of Chicago Press, 2009], p. 77, note 54 and p. 110, note 10: “In the errata that she was allowed to submit, she changed a reference to Dortous de Mairan’s formula for force to that of Bernoulli. She had been reading Bernoulli and Leibniz on the nature of collisions and had changed her mind.”
- Dissertation, p. 128.
- du Châtelet describes it on page 459 ff. of the Institutions physiques.
- Jakob Hermann, “De mensura virium corporum,” Commentarii Academiae Scientiarum Imperialis Petropolitanae 1 (1726, published 1728): 14.
- de Mairan, “Lettre sur la question des forces vives,” in du Châtelet, Institutions Physiques, p. 487 ff.
- cf. Leibniz’s “Essay de Dynamique sur les loix du mouvement,” unpublished at the time, in Leibnizens Mathematische Schriften, ed. Carl Immanuel Gerhardt, Bd. 6 [Halle: H. W. Schmidt, 1860], p. 215.
- Institutions physiques, p. 529.
- cf. Boudri’s interesting interpretation. However, ‘s Gravesande mentions this experiment in Essai d’une nouvelle théorie du choc des corps and not in Nouvelles expériences, as Boudri claims. Christiaan Boudri, What Was Mechanical about Mechanics: The Concept of Force between Metaphysics and Mechanics from Newton to Lagrange, trans. Sen McGlinn [Dordrecht: Kluwer Academic Publishers, 2002], p. 108.
- Institutions physiques, pp. 466-467. For this passage, I consulted the translation by I. Bour and J. P. Zinsser; Du Châtelet, Selected Philosophical…, pp. 196-197. There are, however, small inaccuracies. E.g. “He took a firm ball of clay and, using Mariotte’s Machine…” See ‘s Gravesande’s description on p. 236: “…une pièce de bois bien affermie par des vis, dans laquelle il y avoit de chaque côté une cavité en demi-sphère, qui servoit à affermir une boule de terre glaise…” ‘s Gravesande, “Essai d’une nouvelle théorie du choc des corps,” in Oeuvres philosophiques et mathématiques, ed. J. N. S. Allamand [Amsterdam: Rey, 1774], Première Partie, pp. 235-236.
- cf. ‘s Gravesande, Essai d’une nouvelle théorie du choc, p. 219, definition II and du Châtelet’s malicious remark that de Mairan would not like to be hit by a body moving with a considerable force either from the left or from the right side.
- cf. the combination of the loss of velocity and indentation in ‘s Gravesande’s experiment discussed above.
- “Nouvelles expériences,” in Oeuvres philosophiques et mathématiques, Première Partie, p. 284.
A guest post by Hanna Szabelska.
Hanna Szabelska writes …
Gabrielle Émilie le Tonnelier de Breteuil, la Marquise du Châtelet (1706–1749), ambitious femme savante and Voltaire’s muse had an unusual penchant for physics and mathematics, which pushed her towards conducting and discussing experiments.
By way of an example, to show that heat and light, as opposed to rarefaction – the distinctive property of fire – are nothing but its modes that do not necessarily accompany each other, she made use of the phenomenon of bioluminescence while imitating René-Antoine Ferchault de Réaumur’s experiment:
Dails [pholads] and glowworms are luminous without giving off any heat, and water does not extinguish their light. M. Réaumur even reports that water, far from extinguishing it, revives the light of dails [pholads]. I have verified this on glowworms, I have plunged some in very cold water, and their light was not affected. 
Since she held Newton’s experimental precision in the Opticks in high esteem, to the point that she acquired knowledge to do experiments about different degrees of heating among primitive colours on her own , du Châtelet had reservations about Charles du Fay’s attempt to reduce the seven primitive colours to three.
The following passages are characteristic of her reliance on experiments. Letter 152. To Pierre Louis Moreau de Maupertuis [about the first of December 1738]
I know the Optics by Mr Newton nearly by heart and I must confess that I did not think it possible to call into question his experiments on refrangibility.
A tremendous series of experiments [une furieuse suite d’expériences] is necessary to undermine the truth that Mr Newton seems to have felt with all his senses. However, since I have not seen du Fay’s experiments I suspend my judgement… 
However, as much as she was fascinated by the potential of experimental philosophy, du Châtelet had an acute awareness of her own limitations and those of available apparatus. For example, she ventures the generalization that the tactile sensations of various colours differed analogically from the visual ones but admits her inability to conduct a decisive experiment and confides this task to the judges of her essay on fire .
Moreover, one can detect irony in her remarks about a defective camera obscura designed for optical experiments. In a letter to Algarotti she complains that:
The abbé Nollet has sent me my camera obscura, more obscure than ever; he claims that you have found it very clear in Paris: the sun of Cirey must be, therefore, unfavourable to it. 
Imperfect instruments could distort the results of experiments but so could an experimenter’s understanding of them if, like Locke or Leibniz, one takes the camera obscura as a metaphor of both visual perception and ideas based on it. Such epistemological doubts were also preying on du Châtelet’s mind, giving her natural philosophy a metaphysical depth. Thus, having enumerated some great names of experimental philosophy, she comes to the conclusion that:
It seems that a truth that so many competent natural philosophers have not been able to discover is not to be known by humanity. With regard to first principles, only conjectures and probabilities are within our reach. 
Interestingly, for Voltaire, this amalgam of the experimental and the speculative, imbued with the venustas muliebris of style, as Cicero would put it, was just the Marquise’s way of life, expression of her complex personality, philosophical to the backbone, but not easy to deal with.
The Marquise’s experimental inclination, under the spell of Leibnizian speculative philosophy, gave rise to sophisticated arguments, that often elude the language of modern physics. The devil is, as usual, in the details so let’s analyse some of them.
One of the most instructive stories is du Châtelet’s disagreement with Voltaire on the nature of fire, in particular on the question of its weight. While assisting with his experiments (cf. Peter Anstey’s post), she came to different conclusions and started working on her own essay in secret.
Voltaire evidently tried hard to interpret his results through the lens of a Newtonian experimentalist: to show that fire has weight and is subject to the force of gravity. Therefore, he downplays Herman Boerhaave’s reservations concerning the acquisition of weight by heated bodies  and opts for Peter van Musschenbroek‘s interpretation .
I visited an iron forge to do an experiment [exprès] and whilst I was there I had all the scales replaced. The [new] iron scales were fitted with iron chains instead of ropes. After that I had both the heated and the cooled metal within the range of one pound to two thousand pounds weighed. As I never found the smallest difference in their weights I reasoned as follows: the surface of these enormous masses of heated iron had been enlarged due to their dilation, therefore they must have had less specific gravity. So I can conclude – even from the fact that their weight stays the same irrespective of whether they are hot or cool – that fire had penetrated the masses of iron adding precisely as much weight as dilation made them lose, and consequently, fire has real weight. 
To save his Newtonian face, Voltaire jumps to hypotheses in a rather non-Newtonian manner:
However, although no experiment to date seems to have shown beyond any doubt the gravity and impenetrability of fire, it is apparently impossible not to assume them. 
Despite his efforts, Voltaire’s conclusion remains caught in a limbo between mere hypothesis and a proposition deduced from phenomena and generalized by induction.
Of course, Newton would not have been himself had not his rejection of hypotheses been nuanced  but even so the leap in Voltaire’s reasoning seems a hidden thorn in his Newtonian flesh.
The conceptualization of Boerhaave’s experiment offered by du Châtelet is, on the contrary, more consistent with the data than that of her companion . But on the other hand, it opens the way for establishing fire as one of the grand metaphysical principles of the Universe:
…but claiming that fire has weight is to destroy its nature, in a word, to take away its most essential property, that by which it is one of the mainsprings of the Creator. 
The action of fire, whether it is concealed from us or perceptible, can be compared to force vive [living force] and force morte [dead force]; but just as the force of bodies is perceptively stopped without being destroyed, so fire conserves in this state of apparent inaction the force by which it opposes the cohesion of the particles of bodies. And the perpetual combat of this effort of fire and of the resistance bodies offer to it, produces almost all the phenomena of nature. 
The passages above are to be found in both versions of du Châtelet’s essay on fire: the original (1739, reprinted in 1752 by the Academy) and the revised one from 1744 (published by the Marquise’s own assumption by Prault, fils). However, it is worth noting that her conceptual framework became more consistently Leibnizian with time. It is this development that I will discuss in my next post.
- Trans. Isabelle Bour and Judith P. Zinsser; Du Châtelet, Selected Philosophical and Scientific Writings, ed. J. P. Zinsser, Chicago: University of Chicago Press, 2009, p. 64.
- Dail is an obsolete French term for pholade, pholas dactylus. (Du Châtelet, Dissertation sur la nature et la propagation du feu, Paris: Chez Prault, Fils,1744, p. 4.)
- Dissertation, p. 69.
- du Fay, Observations physiques sur le meslange de quelques couleurs dans la teinture, “Histoire de l’Académie royale des sciences … avec les mémoires de mathématique & de physique,” 1737, p. 267.
- Les lettres de la Marquise du Châtelet, ed. Theodore Besterman [Genève: Institut et Musée Voltaire, 1958], vol. 1, pp. 273–274.
- Dissertation, pp. 70–71.
- Letter 63. To Francesco Algarotti, in Cirey, the 20th [of April 1736], Les lettres de la Marquise du Châtelet, vol. 1, p. 112.
- Trans. I. Bour and J. P. Zinsser; Du Châtelet, Selected Philosophical…, p. 71.; Dissertation, p. 17.
- Hermannus Boerhaave, “De artis theoria,” in: Elementa chemiae, Tomus primus, editio altera [Parisiis: Apud Guillelmum Cavelier, 1733], p. 193 ff.
- Petrus van Musschenbroek, Elementa physicæ conscripta in usus academicos, editio prima Veneta [Venetiis: Apud Joannem Baptistam Recurti, 1745], p. 323 ff.
- cf. Bernard Joly, “Voltaire chimiste: l’influence des théories de Boerhaave sur sa doctrine du feu,” Revue du Nord 77, No 312 (1995): 817–843.
- Voltaire, “Essai sur la nature du feu et sur sa propagation,” in Recueil des pièces qui ont remporté le prix de l’Académie royale des Sciences en 1738, par M. Rouillé de Meslay [Paris: de l’Imprimerie Royale, 1739], p. 176.
- Voltaire, “Essai sur la nature du feu,” Recueil, p. 180.
- cf. e.g. William L. Harper, Isaac Newton’s Scientific Method: Turning Data into Evidence about Gravity and Cosmology (Oxford: Oxford University Press, 2011), p. 44.
- Dissertation, p. 24, 33 ff.
- Trans. I. Bour and J. P. Zinsser; Du Châtelet, Selected Philosophical…, p. 80; Dissertation, p. 40.
- Trans. I. Bour and J. P. Zinsser; Du Châtelet, Selected Philosophical…, pp. 84–85; Dissertation, p. 52.
A guest post by Marco Storni.
Marco Storni writes …
Was Maupertuis an experimental philosopher? In a recent post on this blog, Peter Anstey pointed out the many ambiguities one encounters when one raises such a question. The perplexity concerns in particular the seemingly contradictory nature of Maupertuis’ contributions to the Berlin Academy: a forward-looking Newtonian in the 1730s, after he takes over the presidency of the Prussian Academy of Sciences in 1746, Maupertuis’ writings deal with stricto sensu scientific topics no more. Although an Experimental Philosophy and a Mathematics class existed in the Berlin Academy, “Maupertuis didn’t publish a single article in the Experimental Philosophy memoirs […] nor did he publish anything in the Mathematics section” (Anstey, The Ambiguous Status of Maupertuis), but only in the memoirs for Speculative Philosophy. This remark can be further generalized for, after 1746, also Maupertuis’ non-academic writings also deal with non-scientific subjects, including theodicy, the origin of language, and ethics. How can we explain such a change of perspective?
To answer these questions, it is necessary to understand what Maupertuis actually means by “experimental philosophy” and “speculative philosophy”. A key text is the academic address Des devoirs de l’académicien (1750), where Maupertuis discusses one by one the nature and the tasks of the Berlin Academy classes. Whereas experimental philosophy, Maupertuis says, studies natural bodies with all their sensible properties, and mathematics deals with bodies “deprived of the large majority of those properties” (Les œuvres de Maupertuis (ed. 1768), 3, p. 293), speculative philosophy is rather concerned with all the objects that have no sensible properties. In this sense,
The Supreme Being, the human soul, and everything relating the mind are the object of this science. The nature of bodies too, as they are represented in our perceptions, even if they are something else than these very perceptions, falls within its scope (Ibid., p. 293-294).
Speculative philosophy is thus concerned with all the areas experimental philosophy and mathematics do not cover. In fact, speculative philosophy studies the very same objects experimental philosophy and mathematics are concerned with (e.g., natural bodies), but from a different perspective (in the case of natural bodies, from the perspective of the experience of such bodies). Therefore, in Maupertuis’ view, speculative philosophy and experimental philosophy are not necessarily opposed but rather complementary. This is well displayed in his studies on the principle of least action, first formulated as a physical principle (in the academic paper Accord de différentes lois de la nature qui avaient jusqu’ici paru incompatibles, 1744), and then given a metaphysical interpretation (in the Essai de cosmologie, 1750).
Maupertuis says something more on the relationship between “speculative philosophy” and “experimental philosophy” in another text of the 1750s, namely the Lettre sur le progrès des sciences (1752). Here, Maupertuis introduces the notion of “metaphysical experience” that turns out to be interesting for our present concern. If physical experiences have to do with bodies—and in the first half of his career Maupertuis focused on physical experiences—metaphysical experiences deal with the spiritual world. Would it not be possible, Maupertuis asks himself, to operate on the soul by means of physiological modifications on the brain? Likewise, would it not be possible to find out how languages are formed by isolating some children and seeing how they manage to communicate? However quaint all this might seem, it nonetheless indicates that speculative philosophy is for Maupertuis essentially intertwined with experimental philosophy. Ultimately, a large part of Maupertuis’ activity in Berlin might be described as the attempt to construct an “experimental metaphysics”.
On my analysis, Maupertuis’ status as an experimental philosopher turns out to be less ambiguous than it might prima facie seem. In fact, according to Maupertuis, “over so many centuries […] our metaphysical knowledge has made no progress” (Les œuvres de Maupertuis, 2, p. 430) precisely because the method of speculative philosophy was too abstract and arbitrary. Grounding metaphysics on experiences, as he argues, might actually help to stimulate such progress: and this is the objective Maupertuis strives for in his works of speculative philosophy. On the whole, therefore, I incline to read Maupertuis’ mature position as the attempt to reform speculative philosophy out of an experimental approach. I would nonetheless be glad to hear other thoughts on Maupertuis’ experimentalism.