Workshop: Newtonian Debates on Causation

This is the third meeting of the workshop series The early modern debate on causality: roots and perspectives .

25 April 2018

Faculty of Philosophy, room Beta

Programme

13.00-13.50: Carla Rita Palmerino (Radboud Universiteit Nijmegen)

Can God move the world in a straight line?

A medieval thought experiment in the Leibniz-Clarke Correspondence

The famous correspondence between Leibniz and Clarke deals with fundamental physical and metaphysical questions, such as the soul-body interaction, the freedom of will, the composition of matter, the possibility of a vacuum, miracles, gravity, and the nature of space and time. On most of these issues, the disagreement between Leibniz and Clarke results from their conflicting views on God’s role in the world. As Steven Shapin has observed, “the Newtonian schema stressed God’s voluntary capacities, while the Leibnizian cosmology emphasized His intellectual attributes.” In the Correspondence Clarke accuses Leibniz of turning God into a “necessary agent,” while Leibniz blames his correspondent for not doing justice to God’s goodness and rationality.In order to prove that Leibniz’s theory of space implies a limitation of God’s freedom, Clarke invokes an imaginary scenario: “If space was nothing but the order of things coexisting,” as Leibniz claims, then it would follow that “if God should remove in a straight line the whole material world entire, with any swiftness whatsoever; yet it would still always continue in the same place.” This thought experiment, which was used by fourteenth-century authors in order to prove that God should be able to do anything that did not imply a logical contradiction, represents a difficult test case for Leibniz. In some passages of the correspondence, Leibniz invokes the Principle of the Identity of Indiscernibles in order to prove that Clarke’s scenario is impossible, while in other passages he claims that it is simply unreasonable. In my lecture, I will try to shed light on the reasons for Leibniz’s hesitation and also provide a new interpretation of the role that the Principle of the Identity of Indiscernibles plays in the Correspondence.

Break

14.00-14.50: Patrick Connolly ( Lehigh University)

George Cheyne’s Causal Framework

George Cheyne (1671-1743) was a Scottish physician and philosopher often recognized for his efforts to apply a “Newtonian method” in medicine. But Cheyne also wrote a work, the Philosophical Principles of Religion, designed to show how Newtonian findings in physics and astronomy offer evidence for the existence of a providential deity. The goal of this talk will be to explore the causal concepts used in the Principles with special attention to Cheyne’s views on the cause of gravitational attraction. In contrast to a number of early Newtonians who had claimed that continuous divine activity was necessary for gravitational attraction, Cheyne argued that gravitational attraction could be accounted for by appeal to a nonessential power that God superadded to material substances. Cheyne’s views are intriguing in part because of his effort to show that his superaddition model was as effective for the purposes of physico-theology as the continuous divine activity model.

Break

15.00-15.50: Kirsten Walsh ( University of Nottingham)

Inventing Units of Measurement: Causal Reasoning in Newton’s Optics

Anyone who has studied a small amount of classical mechanics will be familiar with the newton: the metric unit of force named after Sir Isaac Newton. It’s a useful unit if you want to go rock climbing or fly a fighter jet. Fewer people have heard of the interval of fits—invented by Newton to explain why a body reflects light of one colour rather than another colour. This unit of measurement allowed Newton to offer both a quantitative theory of coloured bodies (his ‘theory of fits’) and an instrument for measuring extremely small things (in the order of 1/100,000th of an inch). The theory of fits is not recognised as one of Newton’s greatest achievements—partly because, abstracted and formalised in book 2 of the Opticks, it was nearly incomprehensible. I argue, however, that the process by which Newton invented the interval of fits and eventually arrived at his theory of fits is revelatory of the role of causal reasoning in Newton’s natural philosophy.

Break

16.00-16.50: Steffen Ducheyne ( Vrije Universiteit Brussel)

A Newtonian Origin of the Regularity View?

According to Isaac Newton, natural-philosophical research aims at unravelling the causes of empirical effects. Although he relied on the traditional terminology of the causal methods of analysis and synthesis, in the Principia he introduced an innovative and abstract notion of causation that is consistent with his methodological stance that requires neutrality with respect to the cause of gravity. My presentation proceeds from the hypothesis that Newton’s ‘abstract’ notion of causation made it conceptually possible for the generations of (natural-)philosophers after him to gradually erase causation from (natural-)philosophical discourse. Talk about causes was gradually replaced by talk about ‘laws of nature’ whereby these laws were characterised as the rules according to which under phenomena occur. As a result, the traditional aim of natural philosophy, to search for the causes of effects, was replaced by a new aim, to establish the rules according to which phenomena occur. I will try to make my hypothesis plausible by analysing the way in which Pieter van Musschenbroek (1692–1761) made sense of the notion of a ‘law a nature’, which features prominently in his work. In this context, I will mobilize joint work with Pieter Present.

Break

17.00-17.50: Jip van Besouw ( Vrije Universiteit Brussel)

To cause or not to cause: ’s Gravesande on physics and metaphysics

On the basis of his stance towards causal talk in physics, Willem Jacob ’s Gravesande (1688-1742) is often considered as an exemplar of the rigid anti-metaphysical strand of Newtonianism. By taking into account some of ’s Gravesande’s lesser known works, this paper demonstrates that such an interpretation does no justice to his philosophical position. It is true that ’s Gravesande argued that it was impossible for us to know to underlying causes of the physical phenomena. Taking certain views of Locke and Newton to their extremes, he asserted that discussing the causes of the phenomena was a pointless endeavour. As I will show here, this is however best interpreted as a conscious attempt to separate, delimit, and redefine physics and metaphysics as two independent fields of study. Far from opposing causal considerations in general, ’s Gravesande used his separation of physics and metaphysics to move such considerations to the domain of metaphysics. I will end this paper with a short outline of ’s Gravesande’s metaphysics, which elaborates a causally determined world view.

Break

18.00-18.50: Pieter Present ( Vrije Universiteit Brussel)

Petrus van Musschenbroek (1692-1761) on experiments, laws, and causes

In this presentation, I will give an analysis of Petrus van Musschenbroek’s (1692-1761) views on the nature and role of experiments. I will give special attention to the relation between his views on experiments and his views on laws of nature and causes. At several places in his oeuvre, van Musschenbroek explicitly states that the search for causes is part of the practice of experimental philosophy. At other occasions however, he argues that rather than looking for causes, experimental philosophers should be looking for laws. The latter are conceived by him as regularities which can only be discovered by empirical means. In some passages, van Mussschenbroek even states that knowledge of causal relations lies forever outside our reach.

In this presentation, I will illustrate this tension in van Musschenbroek’s thinking, specifically looking at the different ways in which he conceives of the role of experiments in discovering laws and/or causes. Rather than interpreting away the tensions in van Musschenbroek’s work, I will show how they provide an example of a natural philosopher struggling to develop his thinking in the midst of a more general move within natural philosophy from causes to laws.

19.30 Dinner

The workshop is part of the activity of the NWO-veni project “ Occasionalism and the secularisation of early modern science ”, and it is co-organized by Andrea Sangiacomo and Lukas Wolf of the GCMEMT.

Attendance is free, but registration is required. To register please write to Lukas Wolf (l.b.wolf@rug.nl)