Kirsten Walsh writes…
Recently, I have been looking for clear cases of Baconianism in the Principia. In my last post, I offered Newton’s ‘moon test’ as an example of a Baconian crucial instance, ending with a concern about establishing influence between Bacon and Newton. Newton used his calculations of the accelerations of falling bodies to provide a crucial instance which allowed him to choose between two competing explanations. However, one might argue that this was simply a good approach to empirical support, and not uniquely Baconian. In this post, I’ll consider another possible Baconianism: Steffen Ducheyne’s argument that Newton’s argument for universal gravitation resembles Baconian induction.
Let’s begin with Baconian induction (this account is based on Ducheyne’s 2005 paper). Briefly, Bacon’s method of ampliative inference involved two broad stages. The first was a process of piecemeal generalisation. That is, in contrast to simple enumerative induction, shifting from the particular to the general in a single step, Bacon recommended moving from particulars to general conclusions via partial or mediate generalisations. Ducheyne refers to this process as ‘inductive gradualism’. The second stage was a process of testing and adjustment. That is, having reached a general conclusion, Bacon recommended deducing and testing its consequences, adjusting it accordingly.
Ducheyne argues that, in the Principia, Newton’s argument for universal gravitation proceeded according to Baconian induction. In the first stage, Newton’s argument proceeded step-by-step from the motion of the moon with respect to the Earth, the motions of the moons of Jupiter and Saturn with respect to Jupiter and Saturn, and the motions of the planets with respect to the Sun, to the forces producing those motions. He inferred that the planets and moons maintain their motions by an inverse square centripetal force, and concluded that this force is gravity—i.e. the force that causes an apple to fall to the ground. And, in a series of further steps (still part of the first stage), Newton established that, as the Sun exerts a gravitational pull on each of the planets, so the planets exert a gravitational pull on the Sun. Similarly, the moons exert a gravitational pull on their planets. And finally, the planets and moons exert a gravitational pull on each other. He concluded that every body attracts every other body with a force that is proportional to its mass and diminishes with the square of the distance between them: universal gravitation. Moving to the second stage, Newton took his most general conclusion—that gravity is universal—and examined its consequences. He demonstrated that the irregular motion of the Moon, the tides and the motion of comets can be deduced from his theory of universal gravitation.
Ducheyne notes that Newton didn’t attribute this method of inference to Bacon. Instead, he labelled the two stages ‘analysis’ and ‘synthesis’ respectively, and attributed them to the Ancients. However, Ducheyne argues that we should recognise this approach as Baconian in spirit and inspiration.
This strikes me as a plausible account, and it illuminates some interesting features of Newton’s approach. For one thing, it helps us to make sense of ‘Rule 4’:
In experimental philosophy, propositions gathered from phenomena by induction should be considered either exactly or very nearly true notwithstanding any contrary hypotheses, until yet other phenomena make such propositions either more exact or liable to exceptions.
Newton’s claim that, in the absence of counter-instances, we should take propositions inferred via induction to be true seems naïve when interpreted in terms of simple enumerative induction. However, given Newton’s ‘inductive gradualism’, Rule 4 looks less epistemically reckless.
Moreover, commentators have often been tempted to interpret this rule as an expression of the hypothetico-deductive method, in which the epistemic status of Newton’s theory is sensitive to new evidence. Previously, I have argued that, when we consider how this rule is employed, we find that it’s not the epistemic status of the theory, but its scope, that should be updated. Ducheyne’s Baconian interpretation supports this position—and perhaps offers some precedent for it.
Ducheyne’s suggestion also encourages us to re-interpret other aspects of Newton’s argument for universal gravitation in a Baconian light. Consider, for example, the ‘phenomena’. Previously, I have noted that these are not simple observations but observed regularities, generalised by reference to theory. They provide the explananda for Newton’s theory. In Baconian terms, we might regard the phenomena as the results of a process of experientia literata—they represent the ‘experimental facts’ to be explained. This, I think, ought to be grist for Ducheyne’s mill.
Interpreting Newton’s argument for universal gravity in terms of Baconian induction brings the experimental aspects of the Principia into sharper focus. These aspects have often been overlooked for two broad reasons. The first is that the mathematical aspects of the Principia have distracted people from the empirical focus of book 3. I plan to examine this point in more detail in my next post. The second is that the Baconian method of natural history has largely been reduced to a caricature, which has made it difficult to recognise it when it’s being used. Dana Jalobeanu and others have challenged the idea that a completed Baconian natural history is basically a large storehouse of facts. Bacon’s Latin natural histories are complex reports containing, not only observations, but also descriptions of experiments, advice and observations on the method of experimentation, provisional explanations, questions, and epistemological discussions. We don’t find such detailed observation reports in the Principia, but we do find some of the features of Baconian natural histories.
So, Ducheyne’s interpretation of Newton’s argument for universal gravitation in terms of Bacon’s gradualist inductive method proves both fruitful and insightful. However, recall that, in my last post, I worried that the resemblance of Newton’s methodology to Bacon’s isn’t enough to establish that Newton was influenced by Bacon’s methodology. If Bacon was just describing a good, general, epistemic method, couldn’t Newton have simply come up with it himself? He was, after all, an exceptional scientist who gave careful thought to his own methodology. Is Ducheyne’s discussion sufficient to establish influence? What do you think?
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:
- 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.
- 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.
- 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…
Kirsten Walsh writes…
In a recent post, I considered Newton’s use of observation and experiment in the Opticks. I suggested that there is a functional (rather than semantic) difference between Newton’s ‘experiments’ and ‘observations’. Although both observations and experiments were reports of observations involving intervention on target systems and manipulation of independent variables, experiments offered individual, and crucial, support for particular propositions, whereas observations only supported propositions collectively.
At the end of the post, I suggested that, if we view them as complex, open ended series’ of experiments, the observations of books 2 and 3 look a lot like what Bacon called ‘experientia literata’, the method by which natural histories were supposed to be generated. In this post, I’ll discuss this suggestion in more detail, following Dana Jalobeanu’s recent work on Bacon’s Latin natural histories and the art of ‘experientia literata’.
The ‘Latin natural histories’ were Bacon’s works of natural history, as opposed to his works about natural history. A notable feature of Bacon’s Latin natural histories is that they were produced from relatively few ‘core experiments’. By varying these core experiments, Bacon generated new cases, observations and facts. The method by which this generation occurs is called the art of ‘experientia literata’. Experientia literata (often referred to as ‘learned experience’) was a late addition to Bacon’s program, developed in De Augmentis scientiarum (1623). It is a tool or technique for guiding the intellect. By following this method, discoveries will be made, not by chance, but by moving from one experiment to the next in a guided, systematic way.
The following features were typical of the experientia literata:
- The series of observations was built around a few core experiments;
- New observations were generated by the systematic variation of experimental parameters;
- The variation could continue indefinitely, so the observation sequence was open-ended;
- The experimental process itself could reveal things about the phenomena, beyond what was revealed by a collection of facts;
- The trajectory of the experimental series was towards increasingly general facts about the phenomena; and
- The results of the observations were collated and presented as tables. These constituted the ‘experimental facts’ to be explained.
Now let’s turn to Newton’s observations. For the sake of brevity, my discussion will focus on the observations in book 2 part I of the Opticks, but most of these features are also found in the observations of book 2 part IV, and in book 3 part I.
The Opticks book 2 concerned the phenomenon now known as ‘Newton’s Rings’: the coloured rings produced by a thin film of air or water compressed between two glasses. Part I consisted of twenty-four observations. Observation 1 was relatively simple: Newton pressed together two prisms, and noticed that, at the point where the two prisms touched, there was a transparent spot. The next couple of observations were variations on that first one: Newton rotated the prisms and noticed that coloured rings became visible when the incident rays hit the prisms at a particular angle. Newton progressed, step-by-step, from prisms to convex lenses, and then to bubbles and thin plates of glass. He varied the amount, colour and angle of the incident light, and the angle of observation. The result was a detailed, but open ended, survey of the phenomena. Part II consisted of tables that contained the results of part I. These constituted the experimental facts to be explained in propositions in part III. In part IV, Newton described a new set of observations, which built on the discussions of propositions from part III.
When we consider Newton’s observations alongside Bacon’s experientia literata, we notice some common features.
Firstly, the series of observations was built around the core experiment involving pressing together two prisms to observe the rings that appeared.
Secondly, new observations were generated by the variation of experimental parameters: i.e. new observations were generated, first by varying the obliquity of the incident rays, then by varying the glass instruments, then by varying the colour of the incident light, and so on.
Thirdly, the sequence of observations was open-ended. Newton could have extended the sequence by varying the medium, or some other experimental parameter. Moreover, at the end of the sequence, Newton noted further variations to be carried out by others, which might yield new or more precise observations.
Fourthly, the experimental process itself revealed things about the phenomenon, beyond what was revealed by a collection of facts. For example, in observation 1, Newton noticed that increasing the pressure on the two prisms produced a transparent spot. The process of varying the pressure, and hence the thickness of the film of air between the two prisms, suggested to Newton a way of learning more about the phenomenon of thin plates. He realised he could quantify the phenomenon by introducing regularly curved object glasses, which would make the variation in thickness regular, and hence, calculable.
Fifthly, the trajectory of the experimental series was towards increasingly general facts about the phenomenon. Newton began by simply counting the number of rings and describing the sequence of colours under specific experimental parameters. But eventually he showed that the number of rings and their colours was a function of the thickness and density of the film. Thus, he was able to give a much broader account of the phenomenon.
Finally, these general results were collated and presented as tables in part II. Thus, the tables in part II constituted the facts to be explained by propositions in part III.
Many commentators have emphasised the ways that Newton deviated from Baconian method. However, when viewed in this light, book 2 of the Opticks provides a striking example of conformity to the Baconian method of natural history: Newton led the reader from observations in part I, to tables of facts in part II, to propositions in part III. Moreover, it ended with a further series of observations in part IV, emphasising the open-endedness of the art of experientia literata.
In contrast to the observations in book 2, Newton’s experiments in book 1 look like Bacon’s ‘instances of special power’, which are particularly illuminating cases introduced to provide support for specific propositions. I’ll discuss this next time. For now, I’d like to hear what our readers think of my Baconian interpretation of Newton’s observations.
Kirsten Walsh writes…
In my last two posts, I have discussed my alterations to the 20 theses of our project. In this post, I’ll continue to discuss thesis 8.
In 2011, I claimed that:
- 8. The development of Newton’s method from 1672 to 1687 appears to display a shift in emphasis from experiment to mathematics.
But at the start of this year, I replaced this thesis with a new thesis 8:
- 8. In his early work, Newton’s use of the terms ‘hypothesis’ and ‘query’ are Baconian. However, as Newton’s distinctive methodology develops, these terms take on different meanings.
In my last post, I told you that I decided to remove my original thesis 8 because the methodological differences between Newton’s early papers and Principia aren’t as great as I initially thought. This isn’t to say that I now think that the methodology of the 1672 paper is precisely the same as the methodology displayed in Principia. Rather, I don’t think my original thesis 8 captures what is important about these differences.
In today’s post, I’ll tell you about my new thesis 8.
On this blog, we have argued that the early members of the Royal Society adopted the new experimental philosophy in a Baconian form. Newton initially encountered the experimental philosophy in the early- to mid-1660s through his reading of Boyle, Hooke and the Philosophical Transactions. While he never adopted the Baconian method of natural history, other features of his early methodology resemble the Baconian approach. For example, in Newton’s 1672 paper and the debate that followed, his use of experiment and queries, and his anti-hypothetical stance, were recognised and accepted by the Baconian experimental philosophers. Moreover, his 1675 paper, in which he explored his hypothesis of the nature of light, was recognised by his contemporaries as an acceptable use of a hypothesis.
In Newton’s later work, however, hypotheses and queries look quite different.
Firstly, consider Newton’s Opticks. When the Opticks was published in 1704, it contained no hypotheses, and the introduction explicitly stated that:
- “My Design in this Book is not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments.”
Book III ended with a series of queries, which provided directions for further research, in the style of Baconian queries. E.g.:
- “Query 2. Do not the Rays which differ in Refrangibility differ also in Flexibility…?”
However, in the 1706 and 1718 editions, Newton introduced new queries, which explore the nature of light. E.g.:
- “Qu. 29. Are not the Rays of Light very small Bodies emitted from shining Substances?”
Like the earlier queries, these ones set out a new research program. But they are much more speculative than was acceptable according to the Baconian method.
Now consider Newton’s Principia. There are hypotheses in every edition of Principia, but they look nothing like Newton’s 1675 hypothesis. In particular, they do not explore the nature of things. For example:
- “Hypothesis 1. The centre of the system of the world is at rest.”
I have argued that the hypotheses in Principia provide a specific supportive role to theories. These propositions are temporarily assumed in order to draw out the observational consequences of Newton’s theory of gravitation. They are simplifying assumptions; not assumptions about the nature of gravity.
Previously, I have argued that Newton’s methodology should be seen as a three-way epistemic distinction between theories, hypotheses and queries. I call this an ‘epistemic triad’. I claim that Newton took these, already familiar, terms and massaged them to fit his own three-way epistemic distinction. It is important to recognise, therefore, that the triad is a three-way epistemic division, rather than the juxtaposition of three terms of reference. The terms ‘theory’, ‘hypothesis’ and ‘query’ are simply labels for these epistemic categories.
In fact, this is a feature of many of Newton’s innovative concepts. He borrowed familiar terms and massaged them to fit his own needs. I have shown that he did this with his key methodological terms: ‘theory’, ‘hypothesis’ and ‘query’. Steffen Ducheyne has argued that Newton did this in other aspects of his methodology, such as his dual-methods of analysis and synthesis. This suggests that Newton’s labeling and naming of things was very much post hoc. It seems that, when discussing Newton’s methodology, we should emphasize divisions and functions over definitions.
Alberto Vanzo writes…
A while ago, I wrote a post on the late seventeenth-century Italian natural philosopher, Geminiano Montanari. I argued that his stints of speculative reasoning were, after all, compatible with his allegiance to the experimental philosophy. In this post, I will focus on another aspect of Montanari’s experimentalism that appears to clash with his natural-philosophical practice: his view that, before even attempting to explain natural phenomena, we should compile a universal natural history.
The problem: disagreements and errors in natural philosophy
Montanari sees the compilation of a universal natural history as way of overcoming disagreements among philosophers. Having noted the many competing views on what “the first principles of natural things” may be, Montanari explains that this variety is due to the excessive self-confidence of “nearly all great minds”. Instead of jumping to first principles,
- It was necessary to start philosophy from particular things, examining the whole of nature one piece after another, and to amass a rich capital of experiences so as to prepare the historical matter on whose basis one should later speculate about the reasons [of those experiences].
The solution: building a universal natural history
We can avoid errors and reach agreement on the principles of things by following Francis Bacon’s suggestion of building a natural history including “all experiences and other certain information that one could get from faithful sources”.
How much information should be gathered before we can discover the first principles of natural things?
- [I]n order to find what the true, first and most universal principles of all things may be, it is not sufficient to make an induction from few terms, but it is necessary first to cognize all natural effects, so that one can later find a common reason which satisfies all experiences. But who can already boast to possess such an universal information?
Montanari’s answer is: nobody. It is still too early to make an induction from the observation of everything to its first cause. We must postpone the task of explaining the whole of nature and focus our strengths on the task of compiling natural histories.
Did Montanari do what he says?
He certainly collected many experiments and observations on manifold phenomena, from the capillary behaviour of liquids to the comets and celestial bodies. But he did not refrain from developing explanations of those phenomena, even though he was aware that his experiences were limited and many phenomena had not yet been observed. It is tempting to conclude that Montanari did not do what he says, that his allegiance to the Baconian view that a comprehensive data collection must precede natural-philosophical explanations was merely verbal, and that he was merely paying lip-service to the Baconian fashion of the time.
I do not think that this is the case. Montanari claims that completing a universal natural history is necessary to establish the “true, first and most universal principles of all things”. However, he does not claim that completing a universal natural history is necessary to explain specific natural phenomena, nor does he think that we must first establish the first principles of all things in order to explain specific phenomena. On the contrary, Montanari thinks that, upon completing a universal natural history, we will have to to advance piecemeal toward the first principles, by formulating explanations of specific phenomena and proceeding to increasingly higher levels of generality.
Montanari’s two-part discussions of specific phenomena follow, on a small scale, his favoured Baconian method that for establishing first principles. Regardless of whether he is discussing the capillary action, the behaviour of hot spheres of glass in water, or the position of a comet, Montanari starts by providing a natural history of the phenomenon at hand in the form of a list of observations and experiments. He then proceeds from the “historical matter” to its “reasons”, that is, he provides natural-philosophical explanations of the phenomena.
These explanations are fallible. Natural histories are inescapably incomplete and it is always possible that future experiments or observations invalidate his explanations. However, Montanari holds that it is possible to “deduce” explanations “with physico-mathematical evidence” from a suitable, even if limited, natural-historical basis. What warrants his explanations is the fact that they “explain all the other effects we have observed.”
In conclusion, Montanari does not violate his claim that we should build a universal natural history before identifying the very first principles of the whole nature. The magnitude of the task suggests that this may be only a regulative ideal and may even warrant a certain scepticism on whether we will ever be able to discover the first principles. However, discovering these principles is not necessary to do science for Montanari. What drives Montanari’s natural philosophy is the fact that he allows for fallible natural-philosophical explanations which are based on small-scale, necessarily incomplete, subject-specific natural histories.
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.
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.
Kirsten Walsh writes…
- the apparent continuity between Newton’s usage [of the term ‘experimental philosophy’] and that of the early Royal Society is, however, largely an illusion.
I examined his claim that ‘experimental philosophy’ was used as a synonym for ‘mechanical philosophy’ by the early Royal Society, whereas for Newton, the two terms had different meanings.
Today I’ll address another argument Shapiro makes in that paper.
Shapiro claims that Newton’s adoption of the experimental philosophy occurred quite late – while preparing the 2nd edition of Principia, published in 1713. To support this claim, Shapiro argues that, in the 1713 edition of Principia, Newton uses the term ‘experimental philosophy’ for the first time in public. Moreover, the methodology Newton describes in this context is very different to the methodology he describes in his early optical papers. Shapiro writes:
- At this time  for Newton confirmation is by mathematical demonstration and secondarily – only if you think it is worth the bother – by experiment. He clearly believed that a mathematical deductive approach would lead to great certainty and that experiment could provide the requisite certain foundations for such a science, but until the eighteenth century he did not assign experiment a primary place in his methodology.
If Newton’s ‘experimental philosophy’ is a late development, then this provides additional support for Shapiro’s claim that Newton’s experimental philosophy is not continuous with the methodology of his predecessors, the early members of the Royal Society.
In this post, I’ll argue that (1) experiment is a prominent theme in Newton’s methodological statements between 1672 and 1713, and (2) Newton’s methodology has features that suggest the influence of the early Royal Society.
1. Experiment is a prominent theme between 1672 and 1713
There is a strong experimental theme in Newton’s early optical papers (1672-1675). For example, he says:
- the proper Method for inquiring after the properties of things is to deduce them from Experiments.
- I drew up a series of such Experiments on designe to reduce the Theory of colours to Propositions & prove each Proposition from one or more of those Experiments by the assistance of common notions set down in the form of Definitions & Axioms in imitation of the Method by which Mathematicians are wont to prove their doctrines.
- Now the evidence by which I asserted the Propositions of colours is in the next words expressed to be from Experiments & so but Physicall: Whence the Propositions themselves can be esteemed no more then Physicall Principles of a Science.
In the opening paragraph of De Gravitatione (date of composition unknown), Newton says:
- in order, moreover, that … the certainty of its principles perhaps be confirmed, I shall not be reluctant to illustrate the propositions abundantly from experiments as well…
In the 1st edition of Principia (1686), Newton says:
- The principles I have set forth are accepted by mathematicians and confirmed by experiments of many kinds.
And in the 1st edition of Opticks (1704), Newton says:
- My Design in this Book is not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments…
Experiment doesn’t seem secondary to me!
2. Newton’s methodology suggests the influence of the early Royal Society
As we have said before, the Royal Society adopted the experimental philosophy in a Baconian form – according to the Baconian method of natural history. There is good evidence that Newton was familiar with the work of the Royal Society by the time he wrote his first optical paper in 1672: his notebooks show that he took notes from many issues of the Philosophical Transactions and he took careful notes on Boyle’s work. Newton never adopted the Baconian method of natural history. However, other features of Newton’s methodology suggest the influence of the early Royal Society. For example, he made use of queries, he adopted the familiar distinction between theory and hypothesis, he was concerned with experiments, and he rejected speculation and speculative systems.
Shapiro notices that Newton rejected speculative systems, but fails to recognise that Newton wasn’t the first member of the Royal Society to take this stance. On this blog we have provided ample evidence that the early members of the Royal Society railed against speculation. Newton’s anti-speculation and anti-hypothetical stance, while extreme, was still inside the spectrum of acceptable experimental positions. Consider this passage from Hooke’s Micrographa, addressed to the Royal Society:
- The Rules YOU have prescrib’d YOUR selves in YOUR Philosophical Progress do seem the best that have ever yet been practis’d. And particularly that of avoiding Dogmatizing, and the espousal of any Hypothesis not sufficiently grounded and confirm’d by Experiments. This way seems the most excellent, and may preserve both Philosophy and Natural History from its former Corruptions.
Whether or not Newton explicitly identified himself as such, we have good reason to think that Newton’s first optical paper in 1672 was written by an experimental philosopher.
Peter Anstey writes…
One feature of early modern experimental philosophy that has been brought home to us as we have prepared the exhibition entitled ‘Experimental Philosophy: Old and New’ (soon to appear online) is the broad range of disciplinary domains in which the experimental philosophy was applied in the 17th and 18th centuries. Some of the works on display are books from what we now call the history of science, some are works in the history of medicine, some are works of literature, others are works in moral philosophy, and yet they all have the unifying thread of being related in some way to the experimental philosophy.
Two lessons can be drawn from this. First – and this is a simple point that may not be immediately obvious – there is no distinct genre of experimental philosophical writing. Senac’s Treatise on the Structure of the Heart is just as much a work of experimental philosophy as Newton’s Principia or Hume’s Enquiry concerning the Principles of Morals. To be sure, if one turns to the works from the 1660s to the 1690s written after the method of Baconian natural history, one can find a fairly well-defined genre. But, as we have already argued on this blog, this approach to the experimental philosophy was short-lived and by no means exhausts the works from those decades that employed the new experimental method.
Second, disciplinary boundaries in the 17th and 18th centuries were quite different from those of today. The experimental philosophy emerged in natural philosophy in the 1650s and early 1660s and was quickly applied to medicine, which was widely regarded as continuous with natural philosophy. By the 1670s it was being applied to the study of the understanding in France by Jean-Baptiste du Hamel and later by John Locke. Then from the 1720s and ’30s it began to be applied in moral philosophy and aesthetics. But the salient point here is that in the early modern period there was no clear demarcation between natural philosophy and philosophy as there is today between science and philosophy. Thus Robert Boyle was called ‘the English Philosopher’ and yet today he is remembered as a great scientist. This is one of the most important differences between early modern x-phi and the contemporary phenomenon: early modern x-phi was endorsed and applied across a broad range of disciplines, whereas contemporary x-phi is a methodological stance within philosophy itself.
What is it then that makes an early modern book a work of experimental philosophy? There are at least three qualities each of which is sufficient to qualify a book as a work of experimental philosophy:
- an explicit endorsement of the experimental philosophy and its salient doctrines (such as an emphasis on the acquisition of knowledge by observation and experiment, opposition to speculative philosophy);
- an explicit application of the general method of the experimental philosophy;
- acknowledgment by others that a book is a work of experimental philosophy.
Now, some of the books in the exhibition are precursors to the emergence of the experimental philosophy (such as Bacon’s Sylva sylvarum). Some of them are comments on the experimental philosophy by sympathetic observers (Sprat’s History of the Royal Society), and others poke fun at the new experimental approach (Swift’s Gulliver’s Travels). But this still leaves a large number of very diverse works, which qualify as works of experimental philosophy. Early modern x-phi is a genre free zone.
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.
Kirsten Walsh writes…
In an earlier post I demonstrated that, in his early optical papers, Newton is working with a clear distinction between theory and hypothesis. Newton takes a strong anti-hypothetical stance, giving theories higher epistemic status than hypotheses. Newton’s corpuscular hypothesis appears to challenge his commitment to this anti-hypothetical position. Today I will discuss a second challenge to this anti-hypotheticalism: Newton’s use of queries.
Newton’s queries have often been interpreted as hypotheses-in-disguise. But in his early optical papers, Newton’s queries are not hypotheses. In fact, he is building on the method of queries prescribed by Francis Bacon, for whom assembling queries is a specific step in the acquisition and development of natural philosophical knowledge.
To begin, what is Newton’s method of queries? In a letter to Oldenburg, Newton explains that
- “the proper Method for inquiring after the properties of things is to deduce them from Experiments.”
Having obtained a theory in this way, one should proceed as follows: (1) specify queries that suggest experiments that will test the theory; and (2) carry out those experiments.
He then lists eight queries relating to his theory of light and colours, e.g.:
- “4. Whether the colour of any sort of rays apart may be changed by refraction?
“5. Whether colours by coalescing do really change one another to produce a new colour, or produce it by mixing onely?”
He ends the letter, saying:
- “To determin by experiments these & such like Queries which involve the propounded Theory seemes the most proper & direct way to a conclusion. And therefore I could wish all objections were suspended, taken from Hypotheses or any other Heads than these two; Of showing the insufficiency of experiments to determin these Queries or prove any other parts of my Theory, by assigning the flaws & defects in my Conclusions drawn from them; Or of producing other Experiments which directly contradict me, if any such may seem to occur. For if the Experiments, which I urge be defective it cannot be difficult to show the defects, but if valid, then by proving the Theory they must render all other Objections invalid.”
While Newton’s method of queries is experimental, it does not appear to be strictly Baconian. For the Baconian-experimental philosopher, queries serve “to provoke and stimulate further inquiry”. Thus, for the Baconian-experimental philosopher, queries are part of the process of discovery. However, for Newton, queries serve to test the theory and to answer criticisms. Thus, they are part of the process of justification.
Newton uses queries to identify points of difference between his theory and its opponents. For example, in a letter to Hooke he writes:
- “I shall now in the last place proceed to abstract the difficulties involved in Mr Hooks discourse, & without having regard to any Hypothesis consider them in general termes. And they may be reduced to these three Queries.  Whether the unequal refractions made without respect to any inequality of incidence, be caused by the different refrangibility of several rays, or by the splitting breaking or dissipating the same ray into diverging parts;  Whether there be more then two sorts of colours; &  whether whitenesse be a mixture of all colours.”
And in a letter to Huygens, Newton says:
- “Meane time since M. Hu[y]gens seems to allow that white is a composition of two colours at least if not of more; give me leave to rejoyn these Quæres.
“1. Whether the whiteness of the suns light be compounded of the like colours?
“2. Whether the colours that emerg by refracting that light be those component colours separated by the different refrangibility of the rays in which they inhere?”
In both cases, Newton is using queries to steer the debate towards claims that can be tested and resolved by experiment. On both occasions, Newton devotes a considerable amount of space to discussing the experiments that might determine these queries.
These early queries are not hypotheses. Rather, they are empirical questions that may be resolved by experiment. This is not merely a matter of semantics. In the same letter to Hooke, Newton demonstrates this by distinguishing between philosophical queries and hypothetical queries. A philosophical query is one that can be determined by experiment, a hypothetical query cannot. Newton argues that philosophical queries are the only acceptable queries. He equates hypothetical queries with begging the question.
In his later work, Newton’s queries become increasingly speculative, suggesting that they function as de facto hypotheses. Does Newton ultimately reject his early ‘method of queries’?
Next Monday we’ll have a guest post from Greg Dawes on Galileo and the Experimental Philosophy.