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How general was Newton’s experimental philosophy?

Kirsten Walsh writes…

Newton is often taken to have spawned two important, but different, sciences: an experimental science exemplified in the Opticks, and a mathematical science exemplified in the PrincipiaI. Bernard Cohen and George Smith, for example, write:

There is, perhaps, no greater tribute to the genius of Isaac Newton than that he could thus engender two related but rather different traditions of doing science.

Like many commentators, they emphasise the differences between the austere, formal mathematism of Newton’s so-called ‘rational mechanics’ and the complex and sophisticated experimentalism of his work on light and colour.  And so, the two works are typically taken to exemplify very different methodologies.

In contrast, on this blog, I have emphasised the common features, rather than the differences—presenting a more integrated account of Newton’s methodology.  For example, I have argued that his claim, that the Principia is a work of experimental philosophy, is something we should take seriously.  And so the mathematico-experimental method is a feature of both the Opticks and the Principia.  Moreover, I have argued that Newton’s mathematico-experimental method can be broadly characterised by an epistemic triad: a three-way epistemic division between theories, hypotheses and queries.  The epistemic triad drives Newton’s optical work and his rational mechanics in a trajectory from experiment to certainty, using mathematical reasoning.

While the Opticks and the Principia represent two fields to which Newton made important contributions, these impressive tomes do not signify the entirety of his research output—nor even the bulk.  During his lifetime, Newton produced vast quantities of written work on chymistry, theology and Church history, as well as mathematics.  Over several posts, I plan to explore some of this less well-known work in order to learn more about Newton’s methodology.  In particular, I want to see what kinds of methodological continuity, if any, there are between his many projects.

This may seem like a fool’s errand.  Indeed, these lesser-known parts of Newton’s research have a poor reputation.  One idea, floated by Jean-Baptiste Biot in his 1829 biography, was that Newton’s intellectual life divided naturally in two: prior to his mental breakdown in 1692, Newton’s life was sane, rational and scientific, but afterwards was mad, irrational and religious.  And so Newton’s alchemical and theological manuscripts are often dismissed as the half-baked musings of an old man.  In more recent times, however, commentators such as Betty Jo Teeter Dobbs, William R. Newman, Rob Iliffe and Sarah Dry (to name just a few!) have aimed to redress this situation.  They have demonstrated that Newton’s alchemical and theological pursuits were as much a part of his intellectual life as the optics, rational mechanics and mathematics, for which he is famous.  So, firstly, if there was any kind of cleavage, it was not along disciplinary lines, and secondly, these intellectual pursuits should be counted as serious scholarship—not simply to be swept under the proverbial rug.

So what sorts of continuities should we expect to find?  In the remainder of this post, I’ll offer a few preliminary suggestions.

One striking feature of Newton’s published scientific work is how methodologically reflective it was.  Perhaps we should expect similar reflections in his manuscripts on chymistry, theology or Church history.  Indeed, a cursory look at the collection shows that Newton approached chymistry, theology and Church history with the same persistence and vigour that we find in his other work.  Moreover, we can recognise several of the same methodological and foundational concerns.  For example, Newton’s interest in the restoration of an ancient tradition of knowledge that has been lost or corrupted, and the view that reason, hard work and disciplined empirical research are always preferable to speculation.

Another feature of Newton’s work that I have discussed on this blog is what I call his ‘rhetorical style’: Newton borrowed familiar terms and bent them to his own needs.  He is, moreover, best characterised as a methodological omnivore—he read widely on different methodologies and approaches, and selected from among them the best tools for the job.  We might expect to find the same thing in his chymistry and theology.  Again, my preliminary reading offers some support.  Newton appears to have been interested in all aspects of chymistry—a heavily experimental discipline, often with a pragmatic eye to profit, as much about developing chemical technologies and pharmaceuticals as it is about turning base metals into gold.  However, while Newton worked on the typical alchemist’s project of deciphering ancient myths, he doesn’t seem to have drunk the Kool-Aid.  He appears to have been much more concerned with linking his chymical research to his more mainstream science—for example, his matter theory.  In short, in these manuscripts, we can recognise the same desire to penetrate appearances and arrive at the fundamental truths of nature that we find in his physics.

Following on from this, we might also expect to find a concern for unification: the idea that Newton’s many topics of investigation are in fact part of a larger project.  For example, in Query 31 of the Opticks, Newton argues for both ontological and methodological unification.  Again, looking briefly at some of his alchemical manuscripts, we see a similar preoccupation.  Newton’s discussions of the ‘vegetative spirit’, for example, offer insight into the ways in which the various strands of his scholarly endeavours, including chymistry and theology, were united under one grand scheme.

When understanding the development of Newton’s thought, I often find it helpful to distinguish between Public-Newton and Private-Newton.  I have argued that there are important methodological differences between the work that Newton published (and hence, was willing to assert and defend) and the work he kept private.  While the former conforms, in some sense, to the experimental philosophy, the latter is typically much more speculative.  The distinction is particularly useful when considering Newton’s optical work, where we find stark differences between draft material and the final published version.  But I suspect it won’t be so useful once we turn to his chymistry, theology and Church history, where many of Newton’s unpublished manuscripts were in circulation—some only among his closest circle of like-minded friends, and others, much more widely.  And yet, this raises one final issue.  Newton’s efforts to pass off his published work as experimental philosophy may well have been politically motivated: by describing his work as ‘experimental philosophy’, he was signalling his commitment as much to the Royal Society as to observation- and experiment-based theorising.  His chymical, theological and Church history manuscripts were circulated much more privately—and presumably the same political motivations did not apply.  When working outside the jurisdiction of the Royal Society, did Newton conform to the experimental philosophy?

I’d love to hear your thoughts on this!

Locke and the Newtonian Achievement

Kirsten Walsh writes…

In the Principia, Newton claimed to be doing experimental philosophy.  Over my last three posts, I’ve wondered whether we can interpret his so-called ‘experimental philosophy’ as Baconian.  In the first two posts, I identified methodological similarities between Bacon and Newton: first, the use of crucial instances; second, the use of Baconian induction.  In each case, I concluded that, without some sort of textual evidence clearly tying Newton’s method to Bacon’s, such similarities don’t demonstrate influence.  In my third post, I tried a different approach: I considered Mary Domski’s claim that Newton’s Principia should be considered Baconian because members of the Royal Society recognised, and responded to, it as part of the Baconian tradition.  While Domski’s argument was fruitful in helping us better to understand what’s at stake in discussions of influence, I raised several concerns with her narrative.  In this post, I shall address those concerns in more detail.

Let’s focus on Domski’s account of how Locke reacted to Newton’s Principia.  Domski argues that Locke regarded Newton’s mathematical inference as the speculative step in the Baconian program.  That is, building on a solid foundation of observation and experiment, Newton was employing mathematics to reveal forces and causes.  In short, Domski suggests that we read Locke’s Newton as a ‘speculative naturalist’ who employed mathematics in his search for natural causes.  Last time, I expressed two concerns with this account.  Firstly, ‘speculative naturalist’ looks like a contradiction in terms (I have discussed the concept of ‘speculative experimental science’ here), and surely neither Locke nor Newton would have been comfortable with the label.  Secondly, there’s a difference between being part of the experimental tradition founded by Bacon, and being Baconian.  Domski’s discussion of the reception of the Principia establishes the former, but not necessarily the latter.

We can get more traction on both of these concerns by considering Peter Anstey’s account of how the Principia influenced Locke.  Anstey argues that Newton’s achievement forced Locke to revise his views on the role of principles in natural philosophy.  In the Essay, Locke offers a theory of demonstration—the process by which one can reason from principles to certain truths via the agreement and disagreement of ideas.  In the first edition, Locke argued that this method of reasoning was only possible in mathematics and moral philosophy, where one could reason from certain principles.  Due to limitations of human intellect, such knowledge was not possible in natural philosophy.  Instead, one needed to follow the Baconian method of natural history which provided, at best, probable truths.  However, Anstey shows us that, by the late 1690s, Locke had revised his account of natural philosophy to admit demonstration from ‘principles that matter of fact justifie’ (that is, principles that were discovered by observation and experiment).

I now draw your attention to two features of this account.  Firstly, Newton’s scientific achievement—his theory of universal gravitation—as opposed to his successful development of a new natural philosophical method per se forced Locke to revise his position on demonstration from principles.  (A while ago, Currie and I noted that this situation is to be expected, if we take the ESD seriously.)  This feature should make us suspicious of Domski’s claim that Newton’s Principia was taken to exemplify the speculative stage of Baconian natural philosophy.  Locke did not see Newton’s achievement as a system of speculative hypotheses, but as genuinely empirical knowledge, demonstrated from principles that are justified by observation and experiment.  Newton had not constructed a Baconian natural history, but nor had he constructed a speculative system.  Rather, Locke recognised Newton’s achievement as something akin to a mathematical result—one which his epistemological story had better accommodate.  This forced him to extend his theory of demonstration to natural philosophy.  And so, by the late 1690s, we find passages like the following:

“in all sorts of reasoning, every single argument should be managed as a mathematical demonstration; the connection and dependence of ideas should be followed, till the mind is brought to the source on which it bottoms, and observes the coherence all along” (Of the Conduct of the Understanding).

Secondly, Anstey emphasises that Locke didn’t regard Newton’s mathematico-experimental method as Baconian, but only as consistent with his, Locke’s, theory of demonstration.  (Anstey also claims that Locke never fully integrated the revisions required to his view of natural philosophy in the Essay.)  On this blog, we have suggested that, in the 18th century, a more mathematical experimental natural philosophy displaced the natural historical approach.  And Anstey has offered a sustained argument for this position here.  He argues that the break was not clean cut, but in the end in Britain mathematical experimental philosophy trumped experimental natural history.  That this break was not clean cut helps to explain why experimental moral philosophers, such as Turnbull, thought they were pursuing both a Baconian and a Newtonian project, and were quite comfortable with this.

Notice that I’ve shifted from the vexed question of the extent to which Bacon influenced Newton, to a perhaps more fruitful line of enquiry: how Newton influenced Locke and others.  This is no non sequitur.  The members of the Royal Society strove to understand Newton in their terms—namely, in terms of Baconianism and the experimental philosophy.  Here, it seems that two conclusions confront us.  Firstly, we (again) find that Newton was taken as legitimately developing experimental philosophy by emphasising both the role of experimentally-established principles of natural philosophy and the capacity of mathematics to carry those principles forward.  These aspects are, at best, underemphasised in Bacon and certainly missing from the Baconian experimental philosophy adopted by many members of the Royal Society.  Secondly, we see that Newton’s influence on Locke was due, at least in part, to his scientific achievements.  Newton did not argue directly with Locke’s epistemology or method, nor did Locke take Newton’s methodology as a replacement for his own.  Rather, Locke took Newton’s scientific success as an example of demonstration from ‘principles that matter of fact justifie’.  This, in turn, necessitated modifications of his own account.

Understanding Newton’s Principia as part of the Baconian Tradition

Kirsten Walsh writes…

Lately I have been examining Baconian interpretations of Newton’s Principia. First, I demonstrated that Newton’s Moon test resembles a Baconian crucial instance. And then, I demonstrated that Newton’s argument for universal gravitation resembles Bacon’s method of gradual induction. This drew our attention to some interesting features of Newton’s approach, bringing the Principia’s experimental aspects into sharper focus. But they also highlighted a worry: Newton’s methodology resembling Bacon’s isn’t enough to establish that Newton was influenced by Bacon. Bacon and Newton were gifted methodologists—they could have arrived independently at the same approach. One way to distinguish between convergence and influence is to see if there’s anything uniquely or distinctively Baconian in Newton’s use of crucial experiments and gradual induction. Another way would be if we could find some explicit references to Bacon in relation to these methodological tools. Alas, so far, my search in these areas has produced nothing.

In this post, I’ll consider an alternative way of understanding Baconianism in the Principia. I began this series by asking whether we should regard Newton’s methodology as an extension of the Baconian experimental method, or as something more unique. In answering, I have hunted for evidence that the Principia is Baconian insofar as Newton applied Baconian methodological tools in the Principia. But you might think that whether Newton was influenced by Bacon isn’t so relevant. Rather, what matters is how the Principia was received by Newton’s contemporaries. So in this post, I’ll examine Mary Domski’s argument that the Principia is part of the Baconian tradition because it was recognised, and responded to, as such by members of the Royal Society.

Domski begins by dispelling the idea that there was no place for mathematics in the Baconian experimental tradition. Historically, Bacon’s natural philosophical program, centred on observation, experiment and natural history, was taken as fundamentally incompatible with a mathematical approach to natural philosophy. And Bacon is often taken to be deeply distrustful of mathematics. Domski argues, however, that Bacon’s views on mathematics are both subtler and more positive. Indeed, although Bacon had misgivings about how mathematics could guide experimental practice, he gave it an important role in natural philosophy. In particular, mathematics can advance our knowledge of nature by revealing causal processes. However, he cautioned, it must be used appropriately. To avoid distorting the evidence gained via observation and experiment, one must first establish a solid foundation via natural history, and only then employ mathematical tools. In short, Bacon insisted that the mathematical treatment of nature must be grounded on, and informed by, the findings of natural history.

Domski’s second move is to argue that seventeenth-century Baconians such as Boyle, Sprat and Locke understood and accepted this mathematical aspect of Bacon’s methodology. Bacon’s influence in the seventeenth century was not limited to his method of natural history, and Baconian experimental philosophers didn’t dismiss speculative approaches outright. Rather, they emphasised that there was a proper order of investigation: metaphysical and mathematical speculation must be informed by observation and experiment. In other words, there is a place for speculative philosophy after the experimental stage has been completed.

Domski then examines the reception of Newton’s Principia by members of the Royal Society—focusing on Locke. For Locke, natural history was a necessary component of natural philosophy. And yet, Locke embraced the Principia as a successful application of mathematics to natural philosophy. Domski suggests that we read Locke’s Newton as a ‘speculative naturalist’ who employed mathematics in his search for natural causes. She writes:

[O]n Locke’s reading, Newton used a principle—the fundamental truth of universal gravitation—that was initially ‘drawn from matter’ and then, with evidence firmly in hand, he extended this principle to a wide store of phenomena. By staying mindful of the proper experimental and evidentiary roots of natural philosophy, Newton thus succeeded in producing the very sort of profit that Sprat and Boyle anticipated a proper ‘speculative’ method could generate (p. 165).

In short, Locke regarded Newton’s mathematical inference as the speculative step in the Baconian program. That is, building on a solid foundation of observation and experiment, Newton was employing mathematics to reveal forces and causes.

In summary, Domski makes a good case for viewing the mathematico-experimental method employed in the Principia as part of the seventeenth-century Baconian tradition. I have a few reservations with her argument. For one thing, ‘speculative naturalist’ is surely a term that neither Locke nor Newton would have been comfortable with. And for another thing, although Domski has provided reasons to view Newton’s mathematico-experimental method as related to, and a development of, the experimental philosophy of the Royal Society, I’m not convinced that this shows that they viewed the Principia as Baconian. That is to say, there’s a difference between being part of the experimental tradition founded by Bacon, and being Baconian. I’ll discuss these issues in my next post, and for now, I’ll conclude by discussing some important lessons that I think arise from Domski’s position.

Firstly, we can identify divergences between Newton and the Baconian experimental philosophers. And these could be surprising. It’s not, in itself, his use mathematics and generalisations that makes Newton different—Domski has shown that even the hard-out Baconians could get on board with these features of the Principia. The differences are subtler. For example, as I’ve discussed in a previous post, Boyle, Sprat and Locke advocated a two-stage approach to natural philosophy, in which construction of natural histories precedes theory construction. But Newton appeared to reject this two-stage approach. Indeed, in the Principia, we find that Newton commences theory-building before his knowledge of the facts was complete.

Secondly, the account highlights the fact that early modern experimental philosophy was a work in progress. There was much variation in its practice, and room for improvement and evolution. Moreover, its modification and development was, to a large extent, the result of technological innovation and the scientific success of works like the Principia. Indeed, it was arguably the ability to recognise and incorporate such achievements that allowed experimental philosophy to become increasingly dominant, sophisticated and successful in the eighteenth century.

Thirdly, the account suggests that, already in the late-seventeenth century, the ESD framework was being employed to guide, and also to distort, the interpretation and uptake of natural philosophy. By embracing the Principia as their own, the early modern experimental philosophers intervened on and shaped its reception, and hence, the kind of influence the Principia had. This raises an interesting point about influence.

As I have already noted, it is difficult to establish a direct line of influence stretching from Bacon to Newton. But, by focusing on how Bacon’s program for natural philosophy was developed by figures such as Boyle, Sprat and Locke, we can identify a connection between Bacon’s natural philosophical program and Newton’s mathematico-experimental methodology. That is, we can distinguish between influence in terms of actual causal connections—Newton having read Bacon, for instance—and influence insofar as some aspect of Newton’s work is taken to be related to Bacon’s by contemporary (or near-contemporary) thinkers. Indeed, Newton could have been utterly ignorant of Bacon’s actual views on method, but the Principia might nonetheless deserve to be placed alongside Bacon’s work in the development of experimental philosophy. Sometimes what others take you to have done is more important than what you have actually done!

“Secta Empírica y Dogmáticos Racionales”: medicine and the ESD in early modern Spain

A couple of months ago Peter Anstey directed me to a book by Miguel Marcelino Boix, a Spanish doctor and professor of surgery at the Universidad de Alcalá. The book, a defense and commentary on the first aphorism of Hippocrates, was published in 1711 and it contains some references to the experimental philosophy of the time. But what really caught my eye was the use Boix makes of the terms rationalism (racionalismo) and empiricism in medicine, and the connection of the latter term to experimental philosophy. In this and a couple of future posts I want to present Boix’s text and hopefully shed some light on the connection between experimental philosophy and empiricism (and the ESD) in early modern Spain.

Vita brevis, ars longa, occasio praeceps, experimentum periculosum, iudicium difficile.

This is Hippocrates’ first aphorism, the focus of Boix’s text. The Spanish doctor gives his analysis of the five phrases of the aphorism while criticizing various other interpretations of them. It is during his account of the fourth phrase, experimentum periculosum, that Boix contrasts the two sects, rational dogmatists (dogmáticos racionales) and empirics (empíricos), and begins to connect the latter with experimental philosophy.

Boix begins by offering his interpretation of the phrase, explaining that it says that doctors “never apply any medicine to the human body with absolute certainty that the desired effect will result.” In this sense, the phrase serves as warning to doctors, both rational and empiric, to be mindful of the limits of our knowledge and experience regarding medicine. However, Boix comments, some rational dogmatists have taken the phrase to mean that “experience is dangerous and false if it is not accompanied by reason.” This interpretation is used by rational dogmatists to attack the empirics, given that they follow experience blindly without any reference to reason. But Boix believes that this description of the empiric doctors, which is popular among people, is flawed. It is this mistaken account of the empirics that leads him to explain the differences between the two sects.

Given that the rational dogmatists attack the empirics for detaching reason from experience, Boix begins by examining the reasons the former give in their accounts.

They (rational dogmatists) say that their Medicine and Philosophy is founded on the four Elements, and the four humours; look at these four columns, these four strong pillars. And so they say, that knowing that there is heat, cold, wet and dry; blood, yellow bile, phlegm and black bile, they know all the effects they want, and that solely with the knowledge of these two quartets they have enough to defeat even the toughest questions contained in Natural philosophy and all of medicine. To this they add, that they are extremely happy, that Galen and Aristotle,their Princes, one in Medicine, the other in Philosophy, knew all they could, because neither to them or their disciples, has a problem been put forward, whether Physical or Medical, that they have not been able to solve solely by knowing that there are four qualities, and four humours.

By contrast, the popular opinion of the empirics is that they focus solely on experience and never give reasons for it; they “are those tricksters or scoundrels that come from Foreign Nations with half a dozen remedies, wanting to cure all kinds of diseases with them.” But this is a false depiction of the empiric sect. In order to explain what the empiric doctors are really about, Boix refers to the main sects in natural philosophy: sceptics, academics, and rational dogmatists. But we will get into that in my next post. I want to stop here to talk about the popular concept of the empiric doctors and the connection with experimental philosophy.

As Alberto Vanzo pointed out in a previous post, “experimental physicians” saw themselves as opponents of “empirical physicians.” But the text by Boix brings in a new scenario for our consideration. It seems that in Spain, rather than seeing themselves as opponents of the empirical physicians, experimental physicians felt that were indeed part of the empiric sect and opposed the rational dogmatists. However, the position of the Spanish doctors is not different from that of the physicians described by Alberto in his post. When doctors like John Gregory and Friederich Hoffman described themselves as opponents of the empirical physicians, they had in mind the popular concept of empiric that Boix points out in his text. The Spanish doctors, just like their Scottish and German counterparts, saw themselves as opponents of that specific kind of physician. The difference lies in the fact that Spanish physicians believed that the true empirical physicians were far from the popular depiction of empirics. In fact, the way they described the true empirical doctors is very similar to that of Gregory and Hoffman regarding experimental physicians. It is this description of the empiric sect that we will turn to in my next post.



Experimental Philosophy and Mechanical Philosophy II: The Case of Robert Boyle

Peter Anstey writes …

What is the precise relation between experimental philosophy and mechanical philosophy in the seventeenth century? In my last post I showed how neither Henry More nor Henry Stubbe were particularly clear about this. In this post I examine the view of Robert Boyle.

Boyle is sometimes credited with coining the English term ‘mechanical philosophy’* and he was certainly the first person to use the term ‘experimental philosophy’ in a book title. In 1663 he published Of the Usefulness of Experimental Philosophy which was soon followed by Henry Power’s Experimental Philosophy of 1664.

If we look at frequencies of use in Boyle’s writings, it turns out that he used the term ‘experimental philosophy’ roughly twice as often as ‘mechanical philosophy’ or ‘mechanical hypothesis’. This raw fact is in itself rather telling for those recent historiographical debates over the nature and status of mechanical philosophy in early modern philosophy that almost entirely ignore experimental philosophy. However, the key question is: Were the terms synonyms for Boyle or did they denote two different things?

The best early statement of Boyle’s view of the content of experimental philosophy is in the ‘Proemial Essay’ to Certain Physiological Essays first published in 1661. He starts with a criticism of previous natural philosophers such as Aristotle and Campanella:

they have too hastily, and either upon a few Observations, or at least without a competent number of Experiments, presum’d to establish Principles, and deliver Axioms. (Works of Robert Boyle, 1999–2000, 2: 13)

What experimental philosophers should do instead is:

set themselves diligently and industriously to make Experiments and collect Observations, without being over-forward to establish Principles and Axioms, believing it uneasie to erect such Theories as are capable to explicate all the Phaenomena of Nature, before they have been able to take notice of the tenth part of those Phaenomena that are to be explicated. (Works of Robert Boyle, 2: 14)

This clearly has to do with the role of observation and experiment in relation to theory in the acquisition of knowledge about nature. Now let’s see how Boyle defines the mechanical philosophy. In The Excellency and Grounds of the Mechanical Hypothesis (aka the mechanical or corpuscular philosophy) Boyle states the kernel of the view as follows:

the Universe being once fram’d by God, and the Laws of Motion being setled and all upheld by His incessant concourse and general Providence; the Phænomena of the World  thus constituted, are Physically produc’d by the Mechanical affections of the parts of Matter, and what they operate upon one another according to Mechanical Laws. (Boyle Works, 8: 104)

The mechanical affections referred to here are the shape, size, motion and texture of corporeal bodies.

Now this is really quite different from experimental philosophy. For, it is the sort of theory that one should arrive at as a result of practising experimental philosophy. This is why Boyle’s book The Origin of Forms and Qualities has a ‘speculative part’, which outlines the theoretical content of the mechanical philosophy, and a ‘historical (or experimental) part’, which provides experimental support for the speculative theory. Here is how he describes the relation between the two parts:

it was very much wish’d, that the Doctrines of the new Philosophy (as tis call’d) [i.e. mechanical philosophy] were back’d by particular Experiments; the want of which I have endeavour’d to supply, by annexing some, whose Nature and Novelty I am made believe will render them as well Acceptable as Instructive.

Thus, for Boyle, experimental philosophy and mechanical philosophy are entirely distinct: the former provides the evidential grounds of the latter. This is why, as Dmitri Levitin has shown, Boyle prefers Democritus to Epicurus. In Boyle’s view, the former based his atomism on experimental philosophy, the latter on speculative philosophy. (Levitin, ‘The experimentalist as humanist: Robert Boyle on the history of philosophy’, Annals of Science, 71, 2014, 149–82).

It may be that some philosophers and even natural philosophers conflated experimental philosophy with mechanical philosophy, but in Boyle’s mind they were distinct.


* Actually, the question turns out to be slightly more complicated than it looks because Henry More used the term ‘mechanical hypothesis’ in 1653 (An Antidote against Atheism, 44) and when Boyle first introduces the term in 1661 in Certain Physiological Essays, he uses ‘Mechanical Hypothesis or Philosophy’ (Boyle Works, 2: 87).


Newton the empiricist?

Kirsten Walsh writes…

Recently, Zvi Biener and Eric Schliesser’s long-awaited volume, Newton and Empiricism, appeared on the shelves. The book is an excellent collection of papers, which makes a significant new contribution to the field. Today I want to focus on one aspect of this volume: the decision to frame the collection in terms of empiricism rather than experimental philosophy.

Over the last four years, we have provided many arguments for the superiority of the ESD over the RED. An important line of argument has been to show that ‘experimental philosophy’ and ‘speculative philosophy’ were the key terms of reference used by the actors themselves, and that they characterised their own work in terms of this division. For example, I have argued here, here, here and here that Newton is best understood as an experimental philosopher.

In their introduction, Biener and Schliesser explain their decision. They acknowledge the ‘Otago School’, and argue that, while in general there may be some good reasons to prefer the ESD to the RED, they see various problems with labelling Newton an ‘experimental philosopher’. Their concerns amount to the following: labelling Newton an ‘experimental philosopher’ obscures the idiosyncrasies of his approach to natural philosophy. They argue, firstly, that the label belies the significant influence of non-experimental philosophers on Newton’s methodology, for example those who influenced his mathematical focus. Secondly, that the label unhelpfully groups Newton with Boyle and Locke, when many features of his work support a different grouping. For example, Newton’s mathematical-system building suggests that his work should be grouped with Descartes’. Thirdly, they argue that the fact that Newton did not employ the label himself until after the publication of the first edition of the Principia suggests that he did not fully identify with the label.

These are important issues about the ESD and Newton’s place in it. So today I want to reflect on the broad problem of Newton’s idiosyncratic position. I argue that Newton’s divergence from Baconian tradition of the Royal Society is best seen as a development of experimental philosophy.

On this blog, I have sketched many features of Newton’s natural philosophical methodology. I have argued that, if we look at Newton from within the framework of the ESD, he can be neatly and easily identified as an experimental philosopher. His use of queries, his cautious approach to hypotheses, and his many methodological statements decrying the construction of metaphysical systems, suggest that this is a label that Newton would have been comfortable with. However, there is an important caveat to note: while Newton was clearly influenced by the Baconian experimental tradition, he did not consider himself a Baconian experimental philosopher.

In the earliest statements of his mathematico-experimental approach, Newton set up his position in opposition to the Baconian experimental philosophers. In these passages, one feature of Newton’s methodology stands out in explicit rejection of the Baconian method: his claims to certainty. This feature, in itself, is not very significant – many experimental philosophers believed that, in the end, natural philosophy would be a form of scientia, i.e. a system of knowledge demonstrated from certain axioms. Indeed, Bacon shared this ideal of certainty. He thought that his method of induction could get around the problems usually associated with ampliative inference and deliver knowledge of the essences of things. Thus, Bacon’s method of natural history was ultimately supposed to provide the axioms on which scientia could be founded. The challenge, which everyone agreed on, was to discover those axioms on which the system would be built.

Newton and the Baconians seem to diverge on their responses to this challenge. Baconian experimental philosophers recommended that one should have all the facts before formulating generalisations or theories. In contrast, Newton thought that a few, or even just one, well-constructed experiment might be enough – provided you used it in the right way. This shows that Newton took a different view of the role of evidence in natural philosophy. This divergence amounts to three key differences between Newton and the Baconian experimental philosophers:

  1. Where the Baconian experimental philosophers advocated a two-stage model, in which construction of natural histories preceded theory construction, Newton appeared to reject this two-stage approach. Newton commenced theory-building before his knowledge of the facts was complete.
  2. Related to (1), the Baconian experimental philosophers conceived of phenomena as immediate facts, acquired via observation, and hence pre-theoretic. In contrast, Newton’s phenomena were generalised regularities, acquired via mediation between observation and theory.
  3. For the Baconian experimental philosophers, queries were used to give direction and define the scope of the inquiry. But Newton’s queries were more focussed on individual experiments.

There is strong textual evidence that the ESD was operative in Newton’s early natural philosophical work. We have good reason to suppose that Newton regarded his natural philosophical pursuits as experimental philosophy. This becomes clearer in Newton’s later work. For instance, in the General Scholium to the Principia (1713), Newton explicitly described his work as ‘experimental philosophy’ – indeed, Peter Anstey has noted that Roger Cotes also recognised this feature of Newton’s work. We also have good reason to suppose that, in important ways, Newton saw his work as aligned with the Royal Society and, by extension, with the Baconian movement. But Newton was also a mathematician, and he saw a role for mathematical reasoning in experimental philosophy. In many ways, it was this mathematical approach that led to his divergence from the Baconian experimental philosophy.

Biener and Schliesser are right to draw attention to the ways in which Newton’s position diverged from the experimental tradition of the Royal Society. However, they fail to recognise that Newton’s position diverged in a way that should be viewed as a development of this tradition. Indeed, the ‘Newtonian experimental philosophy’ eventually replaced the experimental philosophy of Boyle, Hooke and the other early members of the Royal Society.  The label ’empiricism’ has no such historical relevance.  But, more on this another time…

‘Epistemic amplification’ and Newton’s laws


Kirsten Walsh writes…

In my last post, I considered the experimental support Newton offers for his laws of motion. In the scholium to the laws, Newton argues that his laws of motion are certainly true. However, in support he only cites a handful of experiments and the agreement of other mathematicians. I suggested that the experiments discussed do support his laws, but only in limited cases. This justifies their application in Newton’s mathematical theory, but does not justify Newton’s claims to certainty. In this post, I will speculate that the laws of motion were in fact better established than Newton’s discussion suggests. I introduce the notion ‘epistemic amplification’ – suggesting that Newton’s laws gain epistemic status by virtue of their relationship to the propositions they entail. That is, by reasoning mathematically from axioms to theorems, the axioms obtained higher epistemic status, and so the reasoning process effectively amplified the epistemic status of the axioms.

I am not arguing that epistemic amplification captures Newton’s thinking. In fact, Newton explicitly stated that epistemic gain was not possible. For him, the best one could achieve was avoiding epistemic loss. (I have discussed Newton’s aims of certainty and avoiding epistemic loss here and here.) I suggest that, objectively speaking, the epistemic status of Newton’s laws increases over the course of the Principia.

To begin, recall that Newton has two projects in relation to the laws:

  1. The specification of the laws as the axioms of a mathematical system; and
  2. The justification of laws as first principles in natural philosophy.

Let’s consider the first project. In addition to the support of mathematicians and the experiments that Newton cites, it is plausible that the epistemic status of the laws increases by virtue of their success in the mathematical system: in particular, by entailing Keplerian motion. Kepler’s rules and Newton’s laws of motion have independent evidence: as we have seen, Newton’s laws are weakly established by localised experiments and the ‘agreement of mathematicians’; Kepler’s rules are established by observed planetary motion and were widely accepted by astronomers prior to the Principia. Newton’s laws entail Kepler’s rules, which boosts Newton’s justification for his laws. Moreover, Newton’s laws provide additional support for Kepler’s rules, by telling us about the forces required to produce such motions. The likelihood of the two theories is coupled: evidence for one carries over to the other. So Newton’s laws also boost the justification for Kepler’s rules. Thus, Newton achieves epistemic gain: the epistemic status of the laws, qua mathematical axioms, has increased by virtue of their relationship to Kepler’s rules.

Now let’s consider the second project – the application of the laws to natural philosophy. Again, the discussion in the scholium justifies their use, but not their certainty. I now suggest that these laws, as physical principles, gain epistemic status through confirmation of Newton’s theory. This occurs in book 3, when Newton explicitly applies his mathematical theory to natural phenomena. As I have previously discussed, the phenomena (i.e. the motions of the planets and their moons) are employed as premises in Newton’s argument for universal gravitation. However, the phenomena also support the application of the mathematical theory to the physical world: they show that the planets and their moons move in ways that approximate Keplerian motion. As we saw above, the laws of motion entail Kepler’s rules. So, since the phenomena support Kepler’s rules, they also support the laws of motion. So this is a straightforward case of theory-confirmation.

There is also scope for theory-testing in book 1. Each time Newton introduces a new factor (e.g. an extra body, or a resisting medium), the mathematical theory is tested. For instance, the contrasting versions of the harmonic rule in one-body and two-body model systems provides a test: it allows the phenomena to empirically decide between two theories, one involving singly-directed central forces, the other involving mutually-interactive central forces. Similarly, the contrasting two-body and three-body mathematical systems provide a test: they allow the phenomena to select between a theory involving pair-wise interactions and a theory involving universal mutual interaction. Moreover, in the final section of book 2, Newton shows that, unlike his theory, Cartesian vortex theory does not predict Keplerian motion. Thus, the phenomena seem to support his theory, and by extension the laws of motion, and to refute the theory of vortices. Again, the laws seem to gain support by virtue of their relationship to the propositions they entail.

To summarise, Newton claims that his laws are certainly true, but the support he gives is insufficient. Here, I have sketched an account in which Newton’s laws gain epistemic status by virtue of their relationship to the propositions they entail. ‘Epistemic amplification’ is certainly not something which Newton himself would have had truck with, but the term does seem to capture the support actually acquired by Newton’s laws in the Principia.  What do you think?



The formation of Boyle’s experimental philosophy

Peter Anstey writes …

It is not entirely clear when Robert Boyle (1627–1691) first used the term ‘experimental philosophy’, but what is clear is that his views on this new approach to natural philosophy began to form in the early 1650s, some years before the term came into common use.

Boyle’s earliest datable use of the term is from his Spring of the Air published in 1660. The reason for the lack of clarity about Boyle’s first use of the term arises from the fact that what appears to be a very early usage survives only in a fragment published by Thomas Birch in his ‘Life of Boyle’ in 1744: no manuscript version is extant. The context of Boyle’s reference to experimental philosophy in this text suggests that this fragment is associated with his ‘Essay of the Holy Scriptures’ composed in the mid-1650s. Boyle speaks of:

those excellent sciences, the mathematics, having been the first I addicted myself to, and was fond of, and experimental philosophy with its key, chemistry, succeeding them in my esteem and applications …

(Works of Robert Boyle, eds Hunter and Davis, London, vol. 12, p. 356)


However, the question of the precise dating of Boyle’s use of the term is hardly as significant as the formation of his views on his distinctive form of natural philosophy. And on this point we have some fascinating and chronologically unambiguous evidence, namely, Boyle’s outline of a work ‘Of Naturall Philosophie’ which dates from around 1654. This short manuscript in Boyle’s early hand survives among the Royal Society Boyle Papers in volume 36, folios 65–6. (It is transcribed in full in Michael Hunter, Robert Boyle 1627–1691: Scrupulosity and Science (Woodbridge, 2000), 30–1.)

In it Boyle outlines the two ‘Principles of naturall Philosophie’. They are Sense and Reason. As for Sense, in addition to its fallibility, Boyle stresses that:

it is requisite to be furnished with observations and Experiments.

Boyle then proceeds to give a set of seven ‘Directions concerning Experiments’. These directions provide an early adumbration of his later experimental methodology. They include the following:

1. Make all your Experiments if you can your selfe [even] though you be satisfyed beforehand of the Truth of them.

3. Be not discouraged from Experimentinge by haveing now & then your Expectation frustrated

5. Get acquainted with Experimentall Books & Men particularly Tradesmen.

7. After you have made any Experiment, not before, reflect upon the uses & Consequences of it either to establish truths, detect Errors, or improve some knowne or give hints of some new Experiment

As for the principle of Reason, Boyle gives five considerations concerning it. What is striking here is that each of them concerns the relation between Reason and experiments:

  1. That we consult nature to make her Instruct us what to beleeve not to confirme what we have beleeved
  2. That a perfect account of noe Experiment is to be looked for from the Experiment it selfe
  3. That it is more difficult then most men are aware of to find out the Causes of knowne effects
  4. That it is more difficult then men thinke to build principles upon or draw Consequences from Experiments
  5. That therefore Reason is not to be much trusted when she wanders far from Experiments & Systematical Bodyes of naturall Philosophie are not for a while to be attempted

Note here the caution about the difficulty of building natural philosophical principles from experiments and the warning about wandering from experiments and premature system building, points that were to become key motifs of the experimental philosophy that blossomed in the 1660s.

It may well be that the movement of experimental philosophy did not emerge until the early 1660s, but the conceptual foundations of its most able exponent were laid nearly a decade before.

Are there any parallel cases of natural philosophers who worked out an experimental philosophy in the early 1650s or was Boyle the first?



Birth stats and Divine Providence

Juan Gomez writes…

In a number of posts in this blog we have examined how some philosophers in the eighteenth century were carrying out moral enquiries by following the experimental method that had achieved so much for natural philosophers. The subtitle of Hume’s famous Treatise clearly states the “attempt to introduce the experimental method in morals,” and we know that Turnbull, Butler and Hutcheson were also using this method in their arguments regarding morality, the human mind, and the existence of God. Regarding this latter issue, theistic philosophers like Butler and Turnbull argued that the order and perfection of the natural world (deduced from facts and observation) was clear proof of the wisdom and goodness of God. In this post I want to examine one of such arguments given not by a moral philosopher, but by a famous physician and mathematician: Dr. John Aburthnot.

Dr. Arbuthnot was a fellow of the Royal Society and Physician to the Queen, a fellow Scriblerian of Swift and Pope, a mathematician and a very interesting figure in general. Best known for his work in medicine and his satires, this fascinating polymath wrote a short paper that appeared in the Philosophical Transactions for 1710 titled “An Argument for Divine Providence, Taken from the Constant Regularity Observ’d in the Births of Both Sexes.” He explains how probability works in a situation involving a two-sided dice, and then proceeds to argue that the number of males and females born in England from 1629 to 1710 shows that it was not mere chance, but rather Divine Providence that explains the regularity between the sexes. Let’s examine his argument in more detail.

Arbuthnot begins by considering the purely mathematical aspect of an event where we want to find out the chances of throwing a particular number of two-sided dice (or a coin for that matter). The simplest case is that of 2 coins, where we have that there is one chance of both coins landing on heads, one chance of both coins landing on tails, and two chances where each of the coins lands on a different side. The mathematical details need not detain us here; the main conclusion drawn form this exposition is that the chances of getting an equal number of heads and tails grows slimmer as the number of coins augments. For example, the chances of this happening with ten coins is less than 25%. If instead of coins we consider all human beings which, Arbuthnott assumes, are born either male or female, the chances of there being equal number of each of the sexes are very, very low.

However, Arbuthnot acknowledges that the physical world is not equivalent to the mathematical, and this changes his calculations. If it was just mere chance that operated in the world, the balance between the number of males and females would lean to one or the other, and perhaps even reach extremes. But this is not the case. In fact, or so Arbuthnott argues, nature has even taken into account the fact that males have a higher mortality rate than females, given that the former “must seek their Food with danger…and that this loss exceeds far that of the other Sex, occasioned by Diseases incident to it, as Experience convinces us.” The wisdom of the Author of nature is witnessed in this situation, as the tables of births in England show that every year slightly more males than females are born, in order to compensate for the loss mentioned above and keep the balance. For example in 1629, Arbuthnot’s table list 5218 males to 4683 females; in 1659, 3209 males to 2781 females; in 1709, 7840 males to 7380 females; and so on for all the years recorded.

Arbuthnot concludes that from his argument “it follows, that it is Art, not Chance , that governs,” and adds a scholium where he states that polygamy is contrary to the law of nature.

What can we make of Arbuthnot’s paper? Instead of discussing how effective the argument is (I leave that for the readers to discuss with us in the comments!!), I want to focus on the fact that Arbuthnot’s argument illustrates the call for the use of mathematics in natural philosophy. Philosophers like Arbuthnot and John Keill thought that the use of mathematics had been neglected in natural philosophy and believed that it should play a greater role. From the 1690’s onwards the work of experimental philosphers reveals this use of mathematics in natural philosophical reasoning. The structure of Arbuthnot’s argument resembles that of the natural philosophers who, like Newton, were using mathematics to explain natural phenomena. The mathematical calculation is extrapolated to the case of human births (in this case). Arbuthnot recognizes an issue central to the application of maths in natural philosophy: while the former deals with abstract objects, the latter deals with the natural world. However, in this particular case Arbuthnot uses the asymmetry between the mathematical and physical realms to show that Divine Providence is a better explanation than mere chance when it comes to the balance and regularity of human births. I would like to hear what our readers think of arguments like the one constructed by Arbuthnot.

Cotes’ Preface and Experiment

Peter Anstey writes…

In my last post I introduced Roger Cotes’ famous Preface to the second edition of Newton’s Principia in order to show its importance as an expression of a commitment to experimental philosophy. In that post I focused on Cotes’ critique of the Cartesian vortex theory and the manner in which this attack on the archetypal speculative philosophy formed the bookends of the Principia. In this post I will discuss the role of experiment in Cotes’ comments on experimental philosophy.

The Preface is actually quite a complex essay that has both polemical and expository agendas. On the one hand, Cotes uses it to give a summary of the main theses of the Principia centred around Newton’s theory of gravity. On the other hand, Cotes uses it to defend the theory of gravity against the charge that it is an occult quality, to defend Newton’s system of the world against the Cartesian vortex theory, and to defend the methodology of the work against rival approaches.

On this latter point, Cotes begins by claiming that Newton’s method is ‘based upon experiment’ (The Principia, eds I.B. Cohen and A. Whitman, Berkeley: University of California Press, 1999, p. 386). One might expect here that Cotes will give a list of the sorts of experimental results that Newton achieved or some reference to crucial experiments, but instead he introduces another set of methodological notions: phenomena, principles, hypotheses, analysis and synthesis. It is only later when appealing to various laws, principles and axioms in his summary of Newton’s system of the world that Cotes refers to experiments.

Here is a summary of Cotes’ account of the method of the Principia. Natural philosophy attempts to derive the causes of all things from the simplest of principles and not from contrived hypotheses. These principles are derived from the phenomena by a two-step process of analysis and synthesis. From select phenomena the forces and simpler laws of these forces are ‘deduced’ by analysis. Then by synthesis ‘the constitution of the rest of the phenomena’ is given. In the case of the Principia the relevant force is gravitational attraction and the relevant law is the inverse square law. Though Cotes throws in the laws of planetary motion claiming that ‘it is reasonable to accept something that can be found by mathematics and proved with the greatest certainty’ (p. 389). He also claims, after presenting a summary of the system of the world, ‘the preceding conclusions are based upon an axiom which is accepted by every philosopher, namely, that effects of the same kind –– that is, effects whose known properties are the same –– have the same causes, and their properties which are not yet known are also the same’. Indeed, ‘all philosophy is based on this rule’ (p. 391).

Where then do experiments fit in this picture? The first mention of experiments is in relation to the law of fall. Cotes refers here to pendulum experiments and to Boyle’s air-pump. Next, Huygens’ pendulum experiments are referred to in the discussion of the determination of the centripetal force of the moon towards the centre of the Earth (p. 389). They then appear in the elaboration of the ‘same effect, same cause’ axiom and its application to the attribution of gravity to all matter. Cotes says ‘[t]he constitution of individual things can be found by observations and experiments’ and from these we make universal judgments (p. 391). Thus, ‘since all terrestrial and celestial bodies on which we can make experiments or observations are heavy, it must be acknowledged without exception that gravity belongs to all bodies universally. … extension, mobility, and impenetrability of bodies are known only through experiments’ and so too is gravity. Finally, in recapping the Newtonian method near the conclusion of the Preface Cotes repeats that ‘honest and fair judges will approve the best method of natural philosophy, which is based on experiments and observations’ (p. 398).

What are we to make of the role of experiments here? First, notice how experiments are appealed to in the establishment of laws and the ‘same effect, same cause’ axiom. Second, it is worth pointing out that the ‘same effect, same cause’ axiom is Newton’s second rule of philosophizing: indeed, Cotes uses the very same example as Newton, namely, the falling of stones in America and Europe (see p. 795). Third, notice how without any explanation Cotes extends experiments to experiments and observations. He begins by saying that there are those ‘whose natural philosophy is based on experiment’ and he ends by saying that ‘the best method of natural philosophy, … is based on experiments and observations’. This is not an equivalent expression and while it is consistent with many other methodological statements by experimental philosophers, it still calls out for explanation.

Has Cotes really given an adequate summary of the method of experimental philosophy and has he captured the manner in which experiments are used in Newton’s reasoning in the Principia? In my view he has not. I’d be interested to hear your views?