Leibniz on Natural Teleology and the Laws of Optics

Abstract

This essay examines one of the cornerstones of Leibniz's defense of teleology within the order of nature. The first section explores Leibniz's contributions to the study of geometrical optics, and argues that his introduction of the "Most Determined Path Principle" or "MDPP" allows him to bring to the fore philosophical issues concerning the legitimacy of teleological explanations by addressing two technical objections raised by Cartesians to non-mechanistic derivations of the laws of optics. The second section argues that, by drawing on laws such as the MDPP, Leibniz is able to introduce a thin notion of teleology that gives him the resources to respond to the most pressing charges of his day against teleological explanations within natural philosophy. Finally, the third section argues that contemporary philosophers have been overly hasty in their dismissal of Leibniz's account of natural teleology, and indeed that their own generally thin conceptions of teleology have left them with few well-motivated resources for resisting his elegant position.

A Justification of Legitimate Teleological Explanations in Physics Education

“…Leibniz argued that final-cause explanations have value because they are 'useful not only for admiring the ingenuity of the great workman, but also for discovering something useful in physics and medicine' (Leibniz, 1988, p. 65). Leibniz used constraint teleology explanations in his work, notably in his Most Determined Path Principle, the claim that light will travel along the path that minimises distance travelled and 'resistance' from the medium it passes through (McDonough, 2009). By contrast with a non-teleological explanation that describes causal mechanisms (for example, in the case of determining the path of a ray of light, by reference to the velocities of light in different media), Leibniz (1998) suggested that invoking final states as causes can be an efficient form of explanation (he argued that the approach enabled Snell to develop his explanation of refraction) and that both causal and teleological explanations are useful approaches.…”

“…Whilst convergence to a 'best' explanation of a phenomenon is assumed to be an aim of scientific research programmes (Lipton, 2004), pedagogy might adopt a pluralistic approach, in which students are introduced to, or are encouraged to develop, multiple explanatory accounts which are compared and critiqued (Etkina & Planinšič, 2015;Trommler & Hammann, 2020). In a pluralistic model, legitimate teleological explanations offer an alternative to mechanistic accounts as they are often more compact, referring to a single constraint rather than multiple mechanisms (McDonough, 2009). Students might compare and contrast a legitimate teleological explanation with a non-teleological account and consider the advantages of each.…”

Powers ontology and the quantum revolution

“…The second, analytical or Hamiltonian model, gives primacy instead to energies and processes (trajectories) over instantaneous forces, relying on the conservation of energy and principles of least action, instead of Newton's laws of motion (McDonough 2008, McDonough 2009). The alternative model begins with the Lagrangian formulation of mechanics, in which whole trajectories are explained via some form of 'least-action' or 'extremal' or 'variational' principle (Yourgrau and Mandelstam 1979, pp.…”

The Heyday of Teleology and Early Modern Philosophy

“…As a universe of monads, everything that happens in the world can be seen to 30. For discussion of this theme in Leibniz's philosophy, see Hirschmann (1988) and McDonough (2008McDonough ( , 2009). be the result of the unfolding of countless mental lives that can, in principle, be seen as being "driven" from behind by efficient causes or "pulled" ahead by final causes.…”

“…30 30 For discussion of this theme in Leibniz's philosophy, see Hirschmann (1988) and McDonough (2008, 2009). …”