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Monthly Archives: May 2014

Scholasticism and natural science in early modern Spain

Juan Gomez writes…

One of the most exciting tasks of my research has been to track the introduction and reception of the ESD in early modern Spain. I have illustrated the adoption and praise of the spirit of experimental philosophy in various texts by the Spanish Novatores, and I looked in a bit more detail at the work of Benito Feijoo (posts 1, 2, and 3). In spite of the insistence to abandon scholastic and Aristotelian methods and science, the progress of natural philosophy in early modern Spain lagged in comparison to the rest of Europe. In fact, the Novatores themselves recognized this lack of progress, as is clear from a letter by Feijoo which I will be sharing with you today.

In 1745 Feijoo published a collection of letters, most of them responding to a range of criticisms directed against his Teatro Critico Universal. Letter 16 in the second volume of that collection is Causas del atraso que se padece en España en orden a las Ciencias Naturales (Causes for the backwardness of Spain regarding the Natural Sciences). Feijoo gives six reasons (causes) for this backwardness, in all of them placing the blame on the scholastic philosophers and their way of thinking.

The first cause is the narrowness of most of the teachers, whom Feijoo describes as “Everlasting ignorants, set on knowing only a few things, for no other reason that they think that there is nothing else to know, aside from those few things they know.” Feijoo goes on to describe this kind of teacher, who only knows scholastic logic and metaphysics, and laughs when hearing words like ‘new philosophy’ or ‘Descartes.’ However, when asked to explain the claims of the new philosophy or those held by Descartes, they stay silent because they have no knowledge of them. (Note: experimental philosophy and new philosophy are not identical, even though the former was sometimes referred to by the latter name. For example, Descartes was commonly regarded as a new philosopher, but not so much as an experimental philosopher.)

People like the teachers described above have spread throughout Spain a disdain for ‘the new’, the second cause identified by Feijoo. They think that, since every sacred doctrine labelled ‘new’ is rejected immediately for being suspicious, the same rule applies for theories about the natural world. So they must reject the teachings of Galileo, Huygens, and Harvey, as well as all the new instruments and machines developed in the seventeenth century, holding on to their scholastic and Aristotelian science as the one true system. Feijoo comments that this attitude backfires, since rejecting anything because it has been labelled ‘new’ entails that there could never have been any progress in natural science (the Aristotelian system was also ‘new’ at some point).

But aside from rejecting the new philosophy because it is ‘suspicious’, the Spanish scholastics also reject it because all it presents is “a few useless curiosities.” (This is the third cause given by Feijoo.) What the scholastics do not realize, Feijoo tells us, is that under this criterion their theories lose against those of the modern: “Which would be more useful: to explore in the physical world the works of the Author of Nature, or to investigate through large treatises derived from the Entity of Reason, and logical and metaphysical abstractions, the fictions of human understanding?” Feijoo also contrasts between the method of learning in the confines of the classroom of the scholastic, and that of the modern, based on experiments and observations.

The fourth cause rests on the mistaken notion held by the scholastics that the new philosophy is identical to Cartesian philosophy. Feijoo comments that although Cartesian philosophy might be new philosophy, new philosophy is not Cartesian philosophy, the same way men are animals but animals are not men. Highlighting the ESD, Feijoo goes on to divide philosophy into two kinds:

“Philosophy, taken in all its extension, can be divided into Systematic and Experimental. The Systematic has many different members, e.g. Pythagoric, Platonic, Peripatetic, Parascelsistic, or Chemical, that of Campanella, that of Descartes, that of Gassendi, etc.”

Feijoo clarifies that he advocates not that the Spaniards embrace one of the former systems, but rather that they do not close their eyes to “Experimental Physics”, which:

“without regard for any system, investigates the causes through the sensible effects; and where it cannot investigate the causes, it settles for the experimental knowledge of the effects… This is the physics that reigns in Nations: the one cultivated by many distinguished Academies as soon as it emerged in France, England, Holland, Etc.”

The achievements of this experimental physics are illustrated by the discoveries regarding our knowledge of the properties of air, of fluids and mechanics, all of them unattainable by relying on the physics of the schools.

Feijoo identifies as the last two causes the mistaken idea that the new philosophy clashes with religion, and the jealousy and pride of the scholastics in Spain that prevented them from accepting the triumphs of other men of science from different European nations. I will not examine them here. Instead I want to conclude the post by pointing out that, not only there is enough evidence to confirm the presence of the ESD (at least in some form) in early modern Spain, but also that it can provide us with an interesting framework to interpret the development of natural philosophy and science in early modern Spain.

Workshop: The Experimental Philosophy, the Mechanical Philosophy, and the Scientific Revolution

A one-day workshop at the Institute of Advanced Study, Durham University:

The Experimental Philosophy, the Mechanical Philosophy, and the Scientific Revolution

9:30am-5:30pm, Thursday 5th June 2014


The Scientific Revolution is often presented as involving the replacement of an Aristotelian world view by the Mechanical Philosophy. Another common theme is that central to the Scientific Revolution is a special emphasis on empirical observation and experiment as providing the basis for science, a theme often captured by the phrase ‘The Experimental Philosophy’. In the seventeenth century and thereafter, the terms ‘The Mechanical Philosophy’ and ‘The Experimental Philosophy’ were sometimes taken to be synonymous. If the Mechanical Philosophy is interpreted as an encouragement to search for explanations that appeal to mechanisms, as in the workings of a clock, then a close link with experiment seems plausible. On the other hand, if that philosophy is understood as a change in the ultimate ontology of the material world, with the replacement of Aristotelian forms by nothing other than moving corpuscles of matter possessing shape and size, then a link with experiment is less plausible. The aim of this workshop is to explore the range of theses that were involved in the Mechanical and Experimental Philosophies, and to explore the relationship between them.


Speakers and titles:

Prof. Alan F. Chalmers (University of Sydney) ‘Qualitative Novelty in Seventeenth-Century Science: Hydrostatics from Stevin to Pascal’.

Prof. Robert Iliffe (University of Sussex) Title to be confirmed

Prof. David M. Knight (Durham University) ‘Clockwork, Chemistry and the Scientific Revolution’.

Mr. Thomas Rossetter (Durham University) ‘No Mechanism for Miracles: John Keill vs. the World Makers’.

Dr. Sophie Weeks (University of York) ‘Experiment and Matter Theory in the Work of Francis Bacon’.

Prof. David Wootton (University of York) ‘In Defence of the Mechanical Philosophy’.


The workshop is open to all but there are limited places available so please email to reserve a place.

There will be a registration fee of £10 to cover lunch and refreshments.

Are Newton’s Laws Experimentally Confirmed?

Kirsten Walsh writes…

Previously on this blog, I have argued that the combination of mathematics, experiment and certainty are an enduring feature of Newton’s methodology.  I have also highlighted the epistemic tension between experiment and mathematical certainty found in Newton’s work.  Today I shall examine this in relation to Newton’s ‘axioms or laws of motion’.

In the scholium to the laws, Newton argues that his laws of motion are certainly true.  In support, however, he cites a handful of experiments and the agreement of other mathematicians: surprisingly weak justification for such strong claims!  In this post, I show how Newton’s appeals to experiment justify the axioms’ inclusion in his system, but not with the certainty he claims.

Newton begins:

    “The principles I have set forth are accepted by mathematicians and confirmed by experiments of many kinds.”

Newton expands on this claim, discussing firstly, Galileo’s work on the descent of heavy bodies and the motion of projectiles, and secondly, the work conducted by Wren, Wallis and Huygens on the rules of collision and reflection of bodies.  He argues that:

  1. The laws and their corollaries have been accepted by mathematicians such as Galileo, Wren, Wallis and Huygens (the latter three were “easily the foremost geometers of the previous generation”);
  2. The laws and their corollaries have been invoked to establish several theories involving the motions of bodies; and
  3. The theories established in (2) have been confirmed by the experiments of Galileo and Wren (which, in turn confirms the truth of the laws).

These claims show us that Newton regards his laws as well-established empirical propositions.  However, Newton recognises that the experiments alone are not sufficient to establish the truth of the laws.  After all, the theories apply exactly only in ideal situations, i.e. situations involving perfectly hard bodies in a vacuum.  So Newton describes supplementary experiments that demonstrate that, once we control for air resistance and degree of elasticity, the rules for collisions hold.  He concludes:

    “And in this manner the third law of motion – insofar as it relates to impacts and reflections – is proved by this theory [i.e. the rules of collisions], which plainly agrees with experiments.”

This passage suggests that the rules of collisions support a limited version of law 3, “to any action there is always an opposite and equal reaction”, and that the rules themselves appear to hold under experimental conditions.  However, this doesn’t show that law 3 is universal: which Newton needs to establish universal gravitation.  This argument is made by showing how the principle may be extended to other cases.

Firstly, Newton extends law 3 to cases of attraction.  He considers a thought experiment in which two bodies attract one another to different degrees.  Newton argues that if law 3 does not hold between these bodies the system will constantly accelerate without any external cause, in violation of law 1, which is a statement of the principle of inertia.  Therefore, law 3 must hold.  As the principle of inertia was already accepted, this supports the application of law 3 to attraction.

Newton then demonstrates law 3’s application to various machines.  For example, he argues that two bodies suspended from opposite ends of a balance have equal downward force if their respective weights are inversely proportional to the distances between the axis of the balance and the points at which they are suspended.  And he argues that a body, suspended on a pulley, is held in place by a downward force which is equal to the downward force exerted by the body.  Newton explains that:

    “By these examples I wished only to show the wide range and the certainty of the third law of motion.”

What these examples in fact show is the explanatory power of the laws of motion – particularly law 3 – in natural philosophy.  Starting with collision, which everyone accepts, Newton expands on his cases to show how law 3 explains many different physical situations.  Why wouldn’t a magnet and an iron floating side-by-side float off together at an increasing speed?  Because, by law 3, as the magnet attracts the iron, so the iron attracts the magnet, causing them to press against one another.  Why do weights on a balance sometimes achieve equilibrium?  Because, by law 3, the downward force at one end of the balance is equal to the upward force at the other end of the balance.  These examples demonstrate law 3’s explanatory breadth.  But these examples do not give us a compelling reason to think that law 3 should be extended to gravitational attraction (which seems to require some kind of action, or attraction, at a distance).

Newton, clearly, is convinced of the strength of his laws of motion.  But this informal, discussion of the experiments he appeals to shows that he ought not be so convinced.  As I see it, Newton has two projects in relation to his 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.

I suggest that the experiments discussed give strong support for the laws in limited cases.  This justifies their application in Newton’s mathematical model, but it does not justify Newton’s claims to certainty.  In modern Bayesian terms, we might say that Newton’s laws have high subjective priors.  In my next post, I shall sketch an account in which Newton’s laws gain epistemic status by virtue of their relationship to the propositions they entail.