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Monthly Archives: May 2011

Anik Waldow on ‘Jean Le Rond d’Alembert and the experimental philosophy’

Anik Waldow writes …

Peter Anstey’s essayJean Le Rond d’Alembert and the experimental philosophy” sets out to confirm his claim that the distinction between experimental philosophy and speculative philosophy “provided the dominant terms of reference for early modern philosophy before Kant” (p.1) by examining the Preliminary Discourse of the Encyclopédie.  Anstey comes to the conclusion that d’Alembert, who identified metaphysical speculation as the reason why experimental science had “hardly progressed” (p.3), was highly influenced by Locke and clearly reflected Newton’s anti-hypothetical stance.

The paper contains two major lines of argument, which are interconnected but possess slightly different focuses. The first is concerned with the correction of our understanding of particular philosophers and their commitment to the experimental tradition of Locke, Boyle and Newton. The second intends to alter the way we approach the history of philosophy. In this context Peter’s discussion of d’Alembert amounts to a defense of a new conceptual scheme that ought to replace the rationalist/empiricist distinction, thus enabling us to correct our knowledge of early modern philosophy in general. I will merely focus here on the first of these two points, leaving my worries concerning Anstey’s suggestion that Newton’s own experimental practice is able to clearly demarcate the line between experimental and speculative natural philosophy for another occasion.

Much of Anstey’s essay hinges on the claim that d’Alembert’s own rational mechanics is not hostile to experimentalism, but “an extreme application of the new Newtonian mathematical method that came to predominate the manner in which the experimental philosophy was understood in the mid-eighteenth century.” (p. 12) Rational mechanics is a discipline committed to an a priori methodology that seems to be diametrically opposed to the inductive practice of the experimenter and her strict quantitative treatment of observable phenomena. And even though one may argue that experiments are in some restricted sense relevant to rational mechanics, it is clear that this discipline is not committed to the kind of “systematic collection of experiments and observations” (Preliminary Discourse to the Encyclopedia of Diderot, trans and intro. Richard N. Schwab, Chicago,1995, p.24) that d’Alembert regards as the defining feature of experimental physics. To identify d’Alembert as a defender of experimentalism therefore requires Anstey to show that there is no contradiction involved in practising rational mechanics, on the one hand, and defending Lockean experimentalism, on the other.

Anstey’s argument is convincing as long as natural philosophy is treated as a whole that is able to integrate various methodologies. In this form the argument makes a good case against the rigid dichotomies that the rationalist/empiricist distinction introduces, because it shows that we need not endorse what I call an ‘either-or conception’ of experimentalism: either we are experimenters and reject rational mechanics as a speculative discipline because of its detachment from observable phenomena; or we conceive of natural philosophy as a broadly mathematical enterprise and attack experimentalism for its lack of scientific rigour.

Having said that, however, I should like to raise the following question. How well supported is Anstey’s claim that d’Alembert believed that rational mechanics, and in particular demonstrative reasoning, was not merely compatible with experimentalism, but an integral part of it? The reason I ask this question is that we must distinguish between two positions: the first accepts demonstrative mathematics as a methodology in an area of natural philosophy that, strictly speaking, does not qualify as experimental in itself; the second endorses the claim that all natural philosophy ought to be experimental. Hence, the first position regards experimentalism as a specific branch of natural philosophy, while the second takes the whole of natural philosophy to be committed to the tenets of experimentalism.

By aligning d’Alembert’s own methodology with Newton’s mathematized experimentalism, Anstey suggests that d’Alembert was a proponent of the second position. However, I think that d’Alembert’s conception of rational mechanics as the queen among the various natural philosophical disciplines reveals him to be more inclined to the first position. In thinking of rational mechanics as taking the lead in the generation of natural philosophical knowledge, d’Alembert turns experimentalism (conceived as the systematic collection of experiments and observations) into no more than a useful addition to a natural philosophical practice firmly rested on a priori reasoning. Experimentalism is here appreciated only in so far as it is able to generate solutions to problems where rational mechanics can advance no further. Or slightly differently put, experimentalism is acknowledged for its usefulness, but far from being regarded as the discipline that gives the whole of natural philosophy its tone and direction.

In short, Anstey’s paper may have shown that d’Alembert sympathized with Lockean experimentalism. However, more needs to be said in order to clarify how it is possible to think of rational mechanics as a discipline that is, in and of itself, experimental in spirit. Otherwise it is hard to see why we should agree with Anstey’s claim that d’Alembert thought of the whole of natural philosophy as an essentially experimental discipline.

Images of Experimental Philosophy (and a request for help!)

Kirsten Walsh writes…

Over the last few weeks, we have been organizing a rare book exhibition* on the history of experimental philosophy.  It has been a privilege to handle dozens of antique books such as a 2nd edition of Newton’s Principia, Bacon’s Opuscula and Kepler’s Epitome.  One of the striking features of early modern books is their ornate frontispieces and detailed illustrations.  They give the impression that publishers spent a lot of money to acquire and print these images.  This got us thinking about what images really capture the spirit of the experimental philosophy.  So this week, we thought we’d do a special post on images of experimental philosophy.

One of my favourite images is Wright’s 1768 ‘An Experiment on a Bird in the Air Pump’.  It combines several aspects of the 18th century scientific pursuit: the experimenter as a ‘show man’, natural philosophy as ‘family entertainment’, and Boyle’s air pump centre stage.  If you want to see some of the experiments that Wright’s subjects might have seen, have a look at the video on air pressure over at Discovering Science.

Wright (1768), An Experiment on a Bird in the Air Pump

Wright (1768), 'An Experiment on a Bird in the Air Pump'

Another wonderful image is Stradanus’ (1580), ‘Lapis Polaris Magnes’, also known as ‘The Philosopher in his Chamber Studying a Lodestone’.

    “the scholar in his study is surrounded by the new instruments of navigation, drafting, and surveying. An armillary sphere, a compass, an octant, several books, and other measuring tools sit on the table at left. In the left foreground, a lodestone floats on a raft of wood in a wine cooler. The model galleon suspended from the ceiling contrasts to the single-masted, oared Mediterranean vessel that can be seen through the window. The juxtaposition of instruments and books on the scholar’s desk indicates the coming together of the hitherto generally separate traditions of practice and theory. Out of their union, the new experimental philosophy emerged.”  (From Experience and Experiment in Early Modern Europe.)
(1580), ‘Lapis Polaris Magnes’ a.k.a. Philosopher in his Chamber Studying a Lodestone

Stradanus (1580), ‘Lapis Polaris Magnes’

Another gallon is represented in the frontispice of Bacon’s De augmentis.  It has passed through the Pillars of Hercules, venturing into the unknown and increasing our knowledge.  The line beneath the ship explains: “Many shall pass through and learning shall be increased” (“Multi pertransibunt & augebitur scientia”).  How shall learning be increased?  By overcoming a series of oppositions: between reason and experience (the motto at the top reads “Reason and Experience have been allied together”); between the visible world and the intelligible world (the two globes at the top); between science and philosophy (the two terms at the bottom of the pillars); and even between Oxford and Cambridge (“Oxonium” and “Cantabrigia”)!

Bacon (1640), De Augmentis Scientiarum

Bacon (1640), 'De Augmentis Scientiarum'

The frontispiece to Voltaire’s (1738) Elemens is not a good representation of the experimental philosophy, but it is a lovely illustration. Voltaire sits at his desk, translating Newton’s Principia.  Heavenly light seems to come from Newton himself, representing his divine inspiration.  The light is reflected downwards to illuminate Voltaire’s work by Voltaire’s lover and muse Émilie du Châtelet (but it was really she who translated Principia and helped Voltaire to make sense of the work).

Voltaire (1738), Elemens de la philosophie de Neuton

Voltaire (1738), 'Elemens de la philosophie de Neuton'

West’s (1816) painting depicts Benjamin Franklin’s famous (or infamous) kite experiment.  In 1752, Franklin flew a kite in a storm to demonstrate that lightning is a form of electricity.  He almost electrocuted himself!

    “As soon as any of the thunder clouds come over the kite, the pointed wire will draw the electric fire from them, and the kite, with all the twine, will be electrified, and the loose filaments of the twine, will stand out every way, and be attracted by an approaching finger. And when the rain has wetted the kite and twine, so that it can conduct the electric fire freely, you will find it stream out plentifully from the key on the approach of your knuckle. At this key the phial may be charged: and from electric fire thus obtained, spirits may be kindled, and all the other electric experiments be performed, which are usually done by the help of a rubbed glass globe or tube, and thereby the sameness of the electric matter with that of lightning completely demonstrated.” (Written by Benjamin Franklin to Peter Collinson, October 19, 1752.)

You can read more about Franklin’s work on electricity at Skulls in the Stars.

Painting Of Benjamin Franklin Touching Key Attached To Kite String In Lightning Storm

West (1816), 'Benjamin Franklin Drawing Electricity from the Sky'

Many of the books we looked at contain beautiful illustrations of instruments and experiments.  These nicely capture the experimental natural philosophy.

Adams (1787), Essays on the Microscope

Adams (1787), 'Essays on the Microscope'

Boyle (1744), The Works of the Honourrable Robert Boyle in five volumes

Boyle (1744), 'The Works of the Honourable Robert Boyle in five volumes'

Hooke (1665), Micrographia

Hooke (1665), 'Micrographia'

(1616) Comfortable Bones, the Skeletons of Adam and Eve

Swanenburgh (1616) 'Comfortable Bones, the Skeletons of Adam and Eve'

But we claim that experimental philosophy went beyond natural philosophy.  Are there any images that capture its wider application?

Finally, I couldn’t resist adding the burning arm chair, which has special significance for our team: it is at once both a nice image of the shift from speculative to experimental philosophy, and a nod to the local ‘scarfie’ (Otago undergraduate) population of Dunedin.  A favourite pastime for scarfies, here in Dunedin, is to burn couches outside their houses!

Burning the proverbial Philosophers Armchair

Burning the proverbial 'Philosopher's Armchair'

We’re looking for an image for our exhibition poster, and we’d like your help.  Have you seen an image that captures the spirit of early modern experimental philosophy?  We’d love to hear from you.  (We’re giving away a one-year subscription to our blog for the reader who provides the best image!)

*The exhibition will be at the Special Collections, Central Library, University of Otago in Dunedin.  It will open in early July at the annual conference of the Australasian Association of Philosophy (AAP).  So don’t forget to have a look at it, if you are coming to Dunedin in July.  For those who cannot come, don’t miss the online version of the exhibition.  We’ll be sure to let you know as soon as it is available.

Keith Hutchison on ‘De Gravitatione’ and Newton’s Mathematical Method

Keith Hutchison writes…

The core of Kirsten Walsh’s paper is a defence of her proposal that Newton’s De Gravitatione was composed after the publication of the new theory of colours (in 1672-3).  Kirsten compares the methodology of the optical writings with that of De Grav. and notes that despite the similarity there are significant differences. Yet the methodology of De Grav. is effectively identical to that of the Principia, so is plausibly interpreted as the one preferred by Newton.  So Newton would have displayed this methodology in the optical writings, Kirsten concludes, had De Grav. already been composed.

Isaac Newton, 1689

Isaac Newton, 1642-1727

Though I am (tentatively) happy with Kirsten’s observation that it is uncontroversial to see Newton’s Principia as deploying the methodology of De Grav., part of the reason for this is surely the fact that the discussion of methodology in De Grav. is so brief, and hardly exemplified in the actual science that Newton so fleetingly displays in his text.  The little that we find in De Grav. does indeed seem concordant with much that happens in the Principia, but it is easy – too easy – to find agreement between a pair of texts if one of them is vague enough.  Given that the identity between the two methodologies is so important to Kirsten’s case, she needs to find some way of sharpening this step of the argument.

She could, for instance, identify far more thoroughly the small differences between the methodology of the optical writings and that of De Grav.  If each of these differences could be consistently found in the Principia as well, Kirsten would have a much better case, as long as there were not something about the optical investigations that required the alternative approach.  Kirsten notes indeed, that Cohen has suggested that the Principia is primarily a mathematical investigation, but the optical work is overwhelmingly experimental.  Cohen seems to be significantly wrong here, for investigations of the context of Newton’s treatment of chromatic aberration show that Newton originally dreamt of creating a mathematical science of colours – until he found that refraction was puzzlingly idiosyncratic, and so unlike the extremely orderly gravitational interaction that provided much of the mathematics of the Principia.  But it remains true that the optical work is saturated with experiment, and it could be this that allows an earlier (?) De Grav. to seem more like the Principia.

Gideon Manning on the Origins of the Experimental/Speculative Distinction

Gideon Manning writes…

Having commented on Peter Anstey’s “The Origins of the Experimental-Speculative Distinction” at the recent symposium in Otago, I am pleased to share a much abbreviated and slightly revised version of my comments.  I limit myself here to making two points.  First, there is reason to believe the Experimental-Speculative Distinction (ESD) is not all it is cracked up to be.  Second, the best place to look for what Peter has called the “pre-history” of ESD might be in the Scholastic distinction and distinct practice of general as opposed to particular physics.

1. Part of what motivates Peter’s interest in the Experimental-Speculative Distinction (ESD) is his belief that in just about every way it is superior to the post-Kantian Rationalism-Empiricism Distinction (RED).  I agree that RED is no good – it’s an idealization and it’s imposed after the fact to tell a self-affirming story about how philosophy was waiting for Kant to come along.  In addition, RED ignores all sorts of interesting characters in early modern philosophy (like Boyle) and further it ignores the shared doctrines between members of the supposedly opposed camps.  Without wanting to defend RED, however, I do want to raise a red flag about ESD’s advantages.  With the sole exception that the terms employed in ESD were used by many of the actors in the late seventeenth and eighteenth century, I see the same worries Peter identifies with RED coming up for ESD.  Specifically, where RED over emphasizes epistemology ESD over emphasizes methodology; where RED admits to too many significations of “empiricism” and “rationalism” ESD admits to too many significations of “experiment” and “experimental”; where RED leaves a demarcation problem with figures like Boyle – and I would add Hobbes and Berkeley – ESD leaves a demarcation problem with figures like Huygens and Descartes.  Put succinctly, the fact that ESD is an actor’s distinction does not mean it is not an idealization imposed to tell a self-affirming story.

2. In passing, Peter notes that Niccolò Cabeo’s commentary on Aristotle’s Meteorology (1646) uses the phrase “experimental philosophy / experimentalis philosophia”.  I urge him to pursue this lead further.  For, there was a Scholastic distinction between two approaches to natural philosophy found in Aristotle’s corpus: physica generalis and physica particularisPhysica generalis is exemplified by Aristotle’s Physics, where he defines the object of natural philosophy, notes the conditions for the possibility of any kind of motion or change, and identifies matter, form, privation and the four causes as the principles of nature. Physica particularis is exemplified by On Generation and Corruption and the fourth book of the Meteorology, where Aristotle defines the object of natural philosophy as corpus potentia sensibile, considers what the object of sense-perception is, and concludes that touch is the most fundamental of all the senses.  Physica generalis is a metaphysical and theoretical or speculative approach to the study of nature since it is based on the conceptual analysis of the concept of a natural body.  Physica particularis is an experimental approach to nature since it is based on an empirical analysis of what is or seems to be given in sense-perception, as Cabeo observed.  Put succinctly, physica particularis was unquestionably experimental with its own experimental philosophy, so if the story of the “new science” and ESD represent a move away from the general to the particular and toward experimentation, we must look closely at physica particularis.

The case of Daniel Sennert further supports this suggestion.  Sennert was aware of the two approaches to natural philosophy in Aristotle’s corpus and as he matured he grew, in Bill Newman’s words, “increasingly impatient with the traditional scholastic focus on the more theoretical side of Aristotle’s thought”.  In fact, in Sennert’s late Hypomnemata physica (1636) he complains about traditional scholastic practice:

    I consider the chief cause of the imperfection of physics to be the fact that in previous centuries those who considered themselves particularly subtle consumed the greatest part of their life in those very general questions about the prime matter, form, privation, motion, and the like, and wore out their time in those disputations repeated so many times ad nauseam. Indeed they never considered the specifics from whose observation their principles should have been derived, or those specifics which should have provided the foundations of medicine and other disciplines…. And this to such a degree that so many wagon-fulls, practically, of commentaries on Aristotle’s books of general physics have been born, stuffed for the greatest part with questions that are not physical, but rather metaphysical, and often empty speculations. But very few are found who would read or comment on Aristotle’s Meteorology, Historia animalium, De partibus animalium, De generatione animalium, and De plantis. (Newman’s translation)

Sennert’s impatience with contemporary Aristotelians (and even his own earlier Aristotelianism) was tied to their preference for the general over the particular.  In focusing on ESD and its history, I think Peter and his group are reminding us what Sennert and his followers knew; that physica particularis was where the action was in the early modern period.

From Experimental Philosophy to Empiricism: 20 Theses for Discussion

Before our recent symposium, we decided to imitate our early modern heroes by preparing a set of queries or articles of inquiry. They are a list of 20 claims that we are sharing with you below. They summarize what we take to be our main claims and findings so far in our study of early modern experimental philosophy and the genesis of empiricism.

After many posts on rather specific points, hopefully our 20 theses will give you an idea of the big picture within which all the topics we blog about fit together, from Baconian natural histories and optical experiments to moral inquiries or long-forgotten historians of philosophy.

Most importantly, we’d love to hear your thoughts! Do you find any of our claims unconvincing, inaccurate, or plainly wrong? Do let us know in the comments!

Is there some important piece of evidence that you’d like to point our attention to? Please get in touch!

Are you working on any of these areas and you’d like to share your thoughts? We’d like to hear from you (our contacts are listed here).

Would you like to know more on some of our 20 claims? Please tell us, we might write a post on that (or see if there’s anything hidden in the archives that may satisfy your curiosity).

Here are our articles, divided into six handy categories:


1. The distinction between experimental and speculative philosophy (ESD) provided the most widespread terms of reference for philosophy from the 1660s until Kant.

2. The ESD emerged in England in the late 1650s, and while a practical/speculative distinction in philosophy can be traced back to Aristotle, the ESD cannot be found in the late Renaissance or the early seventeenth century.

3. The main way in which the experimental philosophy was practised from the 1660s until the 1690s was according to the Baconian method of natural history.

4. The Baconian method of natural history fell into serious decline in the 1690s and is all but absent in the eighteenth century. The Baconian method of natural history was superseded by an approach to natural philosophy that emulated Newton’s mathematical experimental philosophy.


5. The ESD is operative in Newton’s early optical papers.

6. In his early optical papers, Newton’s use of queries represents both a Baconian influence and (conversely) a break with Baconian experimental philosophy.

7. While Newton’s anti-hypothetical stance was typical of Fellows of the early Royal Society and consistent with their methodology, his mathematisation of optics and claims to absolute certainty were not.

8. The development of Newton’s method from 1672 to 1687 appears to display a shift in emphasis from experiment to mathematics.


9. Unlike natural philosophy, where a Baconian methodology was supplanted by a Newtonian one, moral philosophers borrowed their methods from both traditions. This is revealed in the range of different approaches to moral philosophy in the Scottish Enlightenment, approaches that were all unified under the banner of experimental philosophy.

10. Two distinctive features of the texts on moral philosophy in the Scottish Enlightenment are: first, the appeal to the experimental method; and second, the explicit rejection of conjectures and unfounded hypotheses.

11. Experimental philosophy provided learned societies (like the Aberdeen Philosophical Society and the Philosophical Society of Edinburgh) with an approach to knowledge that placed an emphasis on the practical outcomes of science.


12. The ESD is prominent in the methodological writings of the French philosophes associated with Diderot’s Encyclopédie project, including the writings of Condillac, d’Alembert, Helvétius and Diderot himself.


13. German philosophers in the first decades of the eighteenth century knew the main works of British experimental philosophers, including Boyle, Hooke, other members of the Royal Society, Locke, Newton, and the Newtonians.

14. Christian Wolff emphasized the importance of experiments and placed limitations on the use of hypotheses. Yet unlike British experimental philosophers, Wolff held that data collection and theory building are simultaneous and interdependent and he stressed the importance of a priori principles for natural philosophy.

15. Most German philosophers between 1770 and 1790 regarded themselves as experimental philosophers (in their terms, “observational philosophers”). They regarded experimental philosophy as a tradition initiated by Bacon, extended to the study of the mind by Locke, and developed by Hume and Reid.

16. Friends and foes of Kantian and post-Kantian philosophies in the 1780s and 1790s saw them as examples of speculative philosophy, in competition with the experimental tradition.

From Experimental Philosophy to Empiricism

17. Kant coined the now-standard epistemological definitions of empiricism and rationalism, but he did not regard them as purely epistemological positions. He saw them as comprehensive philosophical options, with a core rooted in epistemology and philosophy of mind and consequences for natural philosophy, metaphysics, and ethics.

18. Karl Leonhard Reinhold was the first philosopher to outline a schema for the interpretation of early modern philosophy based (a) on the opposition between Lockean empiricism (leading to Humean scepticism) and Leibnizian rationalism, and (b) Kant’s Critical synthesis of empiricism and rationalism.

19. Wilhelm Gottlieb Tennemann was the first historian to craft a detailed, historically accurate, and methodologically sophisticated history of early modern philosophy based on Reinhold’s schema. [Possibly with the exception of Johann Gottlieb Buhle.]

20. Tennemann’s direct and indirect influence is partially responsible for the popularity of the standard narratives of early modern philosophy based on the conflict between empiricism and rationalism.

That’s it for now. Come back next Monday for Gideon Manning‘s comments on the origins of the experimental-speculative distinction.

(in their terms, “observational philosophers”)

Gleanings from the symposium

Peter Anstey writes…

Two weeks ago about a dozen scholars assembled in Dunedin to discuss the nature and role of the distinction between experimental and speculative philosophy in early modern thought. The focus of our attention was a group of six pre-circulated papers on topics ranging from the origins of the experimental/speculative distinction (ESD) in the early seventeenth century to the emergence of the rationalism/empiricism distinction (RED) in the late eighteenth century. Two important issues arose that I would like to report on here. Both of them raise potential problems for the ESD. Let us examine them in turn.

The first is the issue of demarcation: just how different is the ESD from the RED? When push comes to shove, doesn’t the experimental philosophy really just collapse into empiricism? And isn’t speculative philosophy merely a rebranding of rationalism? Furthermore, given that the RED is so entrenched in early modern scholarship and philosophical pedagogy, there really must be some significant advantages that accrue to the ESD before philosophers of today abandon the RED in favour of the ESD.

The second issue is closely related to the first. It is the problem of classification: does the ESD really do a better job at classifying early modern philosophers than the RED? Is it not the case that Descartes, Spinoza and Leibniz end up being speculative philosophers and Locke, Berkeley and Hume are experimental philosophers? If the ESD categorises along the same fault-line as the RED what advantages accrue to the ESD on the issue of classification?

It is not enough to respond to these two issues by claiming that the great advantage of the ESD is that it is an actors’ category, that is, it is the very distinction that the early moderns themselves used. For, it may be that, in spite of its historical relevance, the RED has more explanatory power and pedagogical utility than the actors’ categories. What are needed are some concrete answers to the issues of demarcation and classification. Happily, I believe that such answers are not too difficult to find.

In response to the issue of demarcation, it is important to note that the early moderns developed the ESD as a means of characterising two very different methodologies in the acquisition of knowledge of nature. (Later it came to have wider application than natural philosophy and medicine, but we will ignore that development here.) As such, it was concerned with the nature and role of experiment, of instruments, of hypotheses, of demonstrative reasoning, and of the faculties of the mind, in the acquisition of knowledge of nature. The RED, by contrast, when it is given a clear definition, is almost always presented as a distinction between two very different theories of knowledge: rationalism being the acceptance of both innate ideas (and principles) and the efficacy of demonstrative reasoning based upon them, independent of experience; empiricism being the denial of innate ideas and the claim that all knowledge of the natural world derives from experience.

Therefore, the ESD encompasses some of the features of the RED, such as the role of demonstrative reasoning and the senses, but it embraces much more. As a result it has greater explanatory range. In particular, it enables us to account for the views of many who were not strictly philosophers (in the modern sense of the word) because it was developed in a period when disciplinary boundaries were quite different from today. For example, it enables us to give a clear and persuasive explanation of Newton’s attitude to hypotheses. It also enables us to explain why Thomas Sydenham was regarded as the archetypal Hippocratic physician. He was not a philosopher and certainly did not have a theory of knowledge, but he did promote most of the salient doctrines of the experimental philosophy in the late seventeenth century, such as decrying hypotheses and promoting natural histories of disease.

In response to the issue of classification, it is important to stress that the ESD was not developed with a view to classifying philosophers, natural philosophers or physicians, so it should not worry us if a philosopher does not fit into either category. It is also important to stress that so successful was the experimental philosophy that by the early eighteenth century the speculative philosopher became something of a straw man. Nevertheless, significant advantages do accrue to the ESD on the question of classification. First, some experimental philosophers were partial to innate ideas. One example is Robert Boyle, yet no one would want to classify him as a rationalist. Second, Thomas Hobbes has proven notoriously difficult to classify as either a rationalist or an empiricist. But given that he was openly opposed to the experimental philosophy, it is both natural and historically accurate to classify him as a speculative philosopher.

I conclude that a careful consideration of both the demarcation problem and the classification problem provides further reasons for accepting the superiority of the ESD. But not all are convinced. Stay tuned for Gideon Manning’s post on Monday in which he expresses reservations about some aspects of our project.