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Tag Archives: Descartes

Cartesian Empiricisms – a Reply

Peter Anstey writes …

The forthcoming book Cartesian Empiricisms edited by Mihnea Dobre and Tammy Nyden promises to extend our knowledge of the experimental practices and philosophy of experiment amongst many of Descartes’ followers.

Dobre, however, claims that the book will offer more than a study of these writers. He says in his recent post that what we find in these neo-Cartesians ‘seems to escape the ESD’ (experimental–speculative distinction, my italics). In what sense might it be true that Cartesians doing experiments might escape the ESD? Is it that the ESD cannot explain them? Or, more strongly, is it that their experimental practices contradict the central tenets of the actors’ categories of experimental philosophy and speculative philosophy? And what is the value of persisting with the term ‘empiricism’ to describe the neo-Cartesians’ engagement with experiment?

In my view, the fact that some Cartesians performed experiments is of great interest, but it is also grist for our mill: it actually enriches the evidential base for the claims that we have made on this blog and in recent publications. For it shows that, like all other speculative systems, Cartesian natural philosophy was also subject to the court of experiment.

We have never claimed that proponents of speculative systems like Cartesianism were necessarily opposed to experimental verification of their theories. Nor have we ever claimed that all experimental philosophers were adamantly opposed to speculation: some were, but others, like Robert Boyle and Robert Hooke, were not.

We have claimed that the Cartesian vortex theory came to be regarded by many as the archetypal speculative theory in natural philosophy. Indeed, this was the virtually the standard view in England from the late 1690s when the term ‘our vortex’ starts to disappear and Newton’s arguments against the Cartesian system began to be widely appreciated. But none of this implies that our claims about the ESD need somehow to be modified. In fact, there is evidence that distaste for speculative system building and a belief in the need for the construction of Baconian natural histories were constituents of the general methodological background to mid-seventeenth-century Parisian natural philosophy. The first article of the constitution of the Montmor academy, which met in Paris from the mid-1650s to around the time of the formation of the Académie des Sciences, says:

The purpose of the company shall not be the vain exercise of the mind on useless subtleties (subtiltés inutiles), but the company shall set before itself always the clearer knowledge of the works of God, and the improvement of the conveniences of life, in the Arts and Sciences which seek to establish them.

The anti-speculative element here is hard to miss. (Interestingly, none of the articles mention experiment.) Furthermore, it is well known that Christiaan Huygens recommended to Colbert that the newly formed Adadémie construct natural histories after the manner of Verulam.

Henry Testelin: Etablissement de l'Academie des sciences et fondation de l'observatoire (1666)

What I am hoping to glean from Cartesian Empiricisms is an answer to the following question:

Did the Cartesians practise a form of experimental philosophy analogous to that of the Fellows of the early Royal Society?

This question is important for a number of reasons. The work of Trevor McClaughlin on Rohault, for example, has shown that early Cartesians carried out experiments. Yet we still lack a detailed assessment of the nature, theory and practice of experiments amongst the neo-Cartesians in the three decades after Descartes’ death. There is no doubt that they performed experiments for illustrative purposes and repeated many classic experiments for pedagogical purposes. But did they engage in experimental programs with a view to acquiring new knowledge of nature and to modifying and developing natural philosophical knowledge?

What makes this issue particularly pressing is that there is evidence from the late 1650s and early 1660s that the natural philosophers who met in the Parisian academies, such as the Montmor academy which included several prominent Cartesians, performed experiments, but were not really practising experimental natural philosophy. Henry Oldenburg reported to Michaelis in April 1659 that the philosophical academies in Paris: ‘are rich in promises, few in performance’ (Corresp. of Oldenburg, 1: 241). Three months later Oldenburg wrote to Boyle from Paris saying:

we have severall meetings here of philosophers and statists which I carry your nevew to, for to study men as well as books; though the French naturalists are more discursive, than active or experimentall. (Corresp. of Oldenburg, 1: 287)

My hope, therefore, is that Cartesian Empiricisms will answer this very pressing question.

Cartesian empiricisms

Mihnea Dobre from the universities of Bucharest and Nijmegen writes…

As readers of this blog know, the classic division between continental Rationalists and British Empiricists fails to provide an accurate picture of the early modern period. The Otago team has already offered extensive evidence of the complexity of seventeenth-century natural philosophy. Replacing the traditional-historiographical distinction between Rationalism and Empiricism (RED) with actor-category division of experimental versus speculative philosophy (ESD) is one step ahead in getting a more meaningful image of the philosophical debates that marked the formation of modern philosophy and science.

However, in this post, I would like to focus on a different aspect, which seems to escape the ESD distinction and further complicates our image of the late-seventeenth century. At the same time, I take this opportunity to announce a forthcoming volume, Cartesian Empiricisms, which Tammy Nyden and I are co-editing in the Springer series on the Studies in History and Philosophy of Science.

While this juxtaposition between “Cartesianism” (which for a long time has been associated with rationalism, armchair philosophizing, speculative thinking, or a purely theoretically driven philosophical approach) and “Empiricism” (which besides its traditional opposition to “Rationalism” is still preferred by many to describe an approach based on experiment and experimentation) might look odd at first, it sheds, in fact, a completely new light upon the development of natural philosophy in the second half of the seventeenth century.

Descartes’s philosophy has been discussed, interpreted and revaluated constantly in our histories of both philosophy and science. Yet, a more in-depth study of what happens after Descartes’s death is missing. We hope Cartesian Empiricisms will fill this gap, contributing to the exploration of some now-forgotten philosophical figures, which were not only prime representatives of the philosophical debates of their time but were opening the possibility of a more experimentally oriented natural philosophy.

After Descartes’s death in 1650, his philosophy was challenged in various ways and one of the most common forms of attack was to disprove it with empirical evidence.  Take, for example, this curious case from the Philosophical Transactions, one of the first scientific journals. On June 3, 1667, an observational report described the puzzling case of a turtle that was still able to move even with her head missing:

there came a Letter from Florence, Written by M. Steno, which has also somewhat perplext the followers of Des Cartes. A Tortoise had its head cut off, and yet was found to move its foot three days after. Here was no Communication with the Conarium [i.e. the pineal gland]. As this seems to have given a sore blow to the Cartesian Doctrine, so the Disciples thereof are here endeavouring to heal the Wound (p. 480).

Such instances that do not cohere with Descartes’s natural philosophy can be found in various places in the new scientific journals, as well as in public debates and philosophical treatises. A well-known case is that of the collision rules that went through a number of critical evaluations during the 1660s. Physics, anatomy, and psychology are among the most heated areas of contestation for Descartes’s natural philosophy. Cartesians reacted to the new challenges by both trying to complement or correct Descartes’s philosophical corpus with needed additions, but also by incorporating into their practices new methods. Cartesian Empiricisms will highlight such attempts:


Ch. 1. Introduction

Section I: Cartesian Philosophy: Receptions and Context

Ch. 2. “Censorship, Condemnations, and the Spread of Cartesianism” by Roger Ariew

Ch. 3. “Was there a Cartesian Experimentalism in the 1660’s France?” by Sophie Roux

Ch. 4. “Dutch Cartesian Empiricism and the Advent of Newtonianism” by Wiep van Bunge

Ch. 5. “Heat, Action, Perception: Models of Living Beings in German Medical Cartesianism” by Justin Smith


Section II: Cartesian Disciplines

Ch. 6. “The Cartesian Psychology of Antoine Le Grand” by Gary Hatfield

Ch. 7. “Experimental Cartesianism and the Occult (1675-1720)” by Koen Vermeir

Ch. 8. “Rohault’s Cartesian Physics” by Mihnea Dobre

Ch. 9. “De Volder’s Cartesian Physics and Experimental Pedagogy” by Tammy Nyden

Ch. 10. “Empiricism without Metaphysics: Regius’ Cartesian Natural Philosophy” by Delphine Bellis

Ch. 11. “Robert Desgabets on the Physics and Metaphysics of Blood Transfusion” by Patricia Easton

Ch. 12. “Rohault, Regis and Cartesian Medicine” by Dennis Des Chene

Ch. 13. “Could a Practicing Chemical Philosopher be a Cartesian?” by Bernard Joly


It is particularly interesting how many of the individual Cartesians discussed in this volume blend theoretical and experimental elements. Experience and experimentation become – for some of them – constitutive parts of their Cartesian natural philosophies, thus making it harder to classify them with our current historiographical categories. We hope that our volume will open new discussions about such categories and will encourage the exploration of other branches of Cartesian philosophy.

Experimental Philosophy in Spain Part II

Juan Gomez writes…

In my previous post I reviewed some texts from Spanish authors in the 17th century to show that, contrary to common opinion, intellectuals in the Iberian Peninsula were in fact acquainted with the progress and achievements of the new experimental philosophy. They did not just know of it, but actually advocated its application and called for the rejection of the old method of the scholastics. In this post I will conclude this overview of the ESD in Spain by looking at the work of the Novatores in the eighteenth century.

The texts we examined in my last post were both written by physicians. In the eighteenth century medicine remained as the forum for the promotion of experimental philosophy. The first author I will examine is Doctor Martín Martínez. He was a physician and professor of anatomy in Madrid, and royal physican to Phillip V. Besides a number of medical writings, in 1730 he published Filosofía Escéptica which consisted in a dialogue between an Aristotlian, a Cartesian, a Gassendist, and a Sceptic. In the preliminaries to this book he tells us that

    The spirit of this book is to give to the Curious Romantics an idea of the most famous philosophies that today run through Europe, relegating that Aristotle just for theological studies.

Even in the 1730’s books in Spain still included a statement of approval made by a priest or friar that confirmed that there was nothing in the book to be censured. The censorship for Filosofía Escéptica was written by Friar Agustín Sanchez and in it we find a statement in the spirit of experimental philosophy. Speaking of the account Martínez gives of the Aristotelian, Cartesian, and Gassendist positions he tells us that the Doctor

    Is determined not to follow any of them, but is inclined towards what he judges more plausible; he does not believe in what experience cannot confirm, based on the fact that words cannot reach the truth of physical and material things, nor their natures and properties; what experience cannot testify, and persuade, cannot be known by words.

Martínez begins his dialogue by giving a brief history of philosophy in Spain, blaming the Arabians for the introduction of Aristotelian philosophy,

    From which that contentious and vociferous philosophy we call Scholastic, as opposed to Experimental, has been derived.

A few lines later Martínez comments that he shares the same opinion held by Bacon:

    The most judicious Verulam also held, that of all the philosophies that have been invented, and received, so many were but fables, and Comical Scenes, each of them making the world to their liking, amassing the Elements to the measure of their palate, and arbitrarily establishing hypotheses as difficult to believe, as they are to prove.

In the case of Martín Martínez we can see the experimental philosophy and the rejection of mere speculation clearly represented. But to show that this was not an isolated case I turn now to another doctor, Andrés Piquer. Out of all the Novatores that practices medicine, Piquer was the one that published most on other topics. He published a book on logic, one on moral philosophy, and one on physics. This last one was published in 1745 under the title Física Moderna Racional, y Experimental (Modern Physics, Rational and Experimental). Piquer begins this book by giving some preliminaries about the state and history of physics and the method to follow. In his historical account he tells us that

    Physics was wrongly cultivated for many centuries, until Francis Bacon Lord Verulam, Great Chancellor of England, towards the end of the sixteenth century, started to renew it, freeing it form the superfluity of reasoning, and manifesting, that the true way to advance in it is through the path of experience.

Speaking about the proper method Piquer sets up a distinction that illustrates the presence of the ESD (in some form) in Spain:

    Modern physicists, are either Systematic, or Experimental. The former explain nature according to some system; the latter discover it through the way of experience. The Systematic form in the imagination some idea, or drawing of the principal parts of the World, of its connections, and mutual correspondence; and holding such idea, that sometimes is strictly willed, as a principle, and foundation of their Philosophy, try to explain everything that occurs in the universe according to it. This has been done by Descartes, and Newton. The Experimental work to collect many experiments, combine them, and use them as the basis of their reasonings. This is how Robert Boyle, Boerhaave, and many other philosophers of these times treat physics.

One of the interesting features of this passage is that Piquer groups Descartes and Newton together under systematic philosophers! However, I don’t have the space or time to discuss this very interesting issue in this post, but Piquer’s distinction between systematic and experimental is something worth looking into. For now, I believe I have provided some very interesting passages from early modern Spanish authors that show that they were acquainted with experimental philosophy and opposed and rejected mere speculation.

N.B. The English translation of the quotes presented here is mine

A Mutual Divide: Experiment vs. (Cartesian) Speculation in Mid-Seventeenth Century Dutch Medicine

This is a guest post by Evan Ragland.

In 1639, the Dutch anatomist and physician Franciscus Dele Boë Sylvius (1614-1672) thrust experimental physiology before the public eye when he demonstrated the Harveian circulation of the blood in the Leiden public gardens. These anatomical investigations unfolded within and partially constituted the growing controversy over the motion of the heart and blood. At some key moments, this controversy resembled the structure and rhetoric of the experimental-speculative distinction.

For the anatomists, Harvey’s description of a muscular heart contracting at systole to expel blood into the arteries was observationally and experimentally proven.  In contrast, many leading anatomists found Descartes’ anatomy to be fallacious and outmoded. Sylvius’ demonstrations convinced one critic, Johannes Walaeus (Jan de Wale, 1604-1649), who became an ardent supporter of the circulation. In 1645, Walaeus attacked the Cartesian explanation of the heart’s motion:

    Certain men with brilliant minds [ingenium praeclarum] judge that the blood is thrust out because it is immeasurably rarefied by the heat of the heart, and so demands a bigger place, and then dilates and lifts up the heart. […] [Yet] in truth the blood does not leap out from the heart on account of the rarefaction, as we have often seen in strong dogs with the tip of their hearts cut off. Because of the outflow of the blood, the heart is not half filled, but still erect: thus, it is not filled by rarefaction. In the subsequent constriction the portion of the blood in the heart was ejected more than four feet, so that we and our neighbors in the large crowd were befouled. From which it is evident that the blood is propelled by the part.

Strikingly, at least one of Descartes’ close friends and supporters, Cornelis van Hogelande (1590-1676), embraced the distinction between experimental and speculative approaches the anatomists propounded, but favored the speculative method.

“The Neoterics,” following after Harvey, added superfluous experimentation to already conclusive reasoning. They proceeded, “not only according to the manifest laws of mechanics […] but, instead, not having enough trust in the grace of reasoning [ratiocinatio], they turned themselves to girding and supplementing these laws with scrutinizing investigations or real and sensual disquisitions, and to dissecting living animals of every kind.”

For his own positive account, Van Hogelande relied on reasoning from mechanical principles. He could, though, throw a bone to the experimentalists:

    As a favor to those who are distrustful of ratiocination and believe experience alone, I will not be amiss in adding on the following easy experiment, in confirmation of the truth of the aforesaid [conclusion]. [Experiment dissecting an eel’s heart, and then adding blood when the motion has ceased, causing increasing motion.] [A]nd I even repeated this experiment in its particularities with similar success, while the printer hurried. Which I add lest anyone assume that I collected those preceding reasons a posteriori (that is, with the experiment having first been done).

This division lasted. In his later medical disputations from the late 1650s and early 1660s, Sylvius set out to resolve the dispute between Harvey and Descartes, “the two most brilliant Lights of this age.” Harvey taught “according to the custom of the Physicians, as well as the Sensible Philosophers, and according to the testimony of the external Senses.” Descartes, on the other hand, “trusting more in the laws of his own Mechanics, rather than in his external Senses, suspected and believed that the Ventricles of the Heart and the Arteries were Dilated and Contracted simultaneously.” Once again, the distinction between experimental anatomy and Cartesian speculation is crisp:

    For whatever even the most subtle and sagacious Genius [Ingenium] is able to think up that is most probable and plausible to the human Mind, every such thought, if it looks to the Medical Art, ought to be suspected as False by the Prudent, until Experience the Teacher of Truth has manifested that it is True, that is, that it has actually been observed in the things themselves as it has been imagined [fingitur].
    God forbid that among the legitimate Sons of Physicians anyone should be discovered who is so lazy, that they […] would rather delight in adhering to his own figments and Chimeras, and to those of others.

Shortly after, Sylvius freely admitted that Descartes was a “famous Mathematician and industrious Philosopher.” Drawing the lines of discipline and identity so that Descartes remained a successful mathematician and philosopher was the gentlest criticism, but one that barricaded him from a place among “the legitimate Sons of Physicians.”

There are, however, complications for this neat typology. Several Dutch anatomists at the time evinced some support for Cartesian philosophy, and later professors of medicine were staunchly Cartesian. And Sylvius repeatedly announced his support for something very like Cartesian mechanism as the preferred and future form of explanation and ontology, even in medicine. Yet a mutual division similar to the ESD remained at the heart of these early anatomical controversies.