[5.0.2] John Philoponus on Place, Space, and Impetus

John Philoponus (490-570 AD) altered the classical Aristoteian theory in some relevant aspects:

  • Lenght, breath, and depth are dimentions
  • Place and space are three-dimensional extensions
  • Substance relates to space
  • Substance relates to impetus
  • Impetus is a kind of energeia

The following OntoUML diagram presents the theory of impetus and space

Philoponus on Place, Space, and Impetus
ClassDescriptionRelations
Place“Aristotle defined the pace of a body as the inner surface of the body or all the bodies taken together that contain it (Phys. IV 4); Philoponus replies that place ought instead to be conceived as the three-dimensional extension identical to the determinate size of the given body, i.e. its volume.” subkind of
Spacespace as a whole is the indeterminate three-dimensional extension everywhere devoid of body, though it is not actually infinite – so much Philoponus concedes to Aristotle. Philoponus’ discussion of matter builds upon this conception of space. […] However, in Book XI of the polemical treatise against Proclus (see below, 3.1) he jettisons the Neoplatonic conception of prime matter and posits as the most fundamental level of his ontology ‘the three-dimensional’, as he calls it, i.e. indeterminately extended mass.
[…] following the Stoics (Aet. 414), and it has been pointed out that this ontological level is reminiscent to us of the Cartesian res extensa, although Descartes would not allow Philoponus’ distinction between space and corporeal extension. In order to rebuff the likely objection that ’the three-dimensional’ cannot be the most fundamental level of being because extension, belonging to the Aristotelian category of quantity, is an accident and requires the assumption of a distinct underlying subject, Philoponus argues that extension is in fact not an accident, but an essential and inseparable differentia of ‘the three-dimensional’, just like heat in fire or whiteness in snow. Thus quantity (corporeal extension) is constitutive of the body as such. This amounts to a promotion of one sort of quantity to the category of substance.”
subkind of
DimensionLenght, breath, and depth are dimensions
Length, Breadth, DepthLength, breadth, and depth are dimensionssubkind of
Substance “Thus quantity (corporeal extension) is constitutive of the body as such. This amounts to a promotion of one sort of quantity to the category of substance.
Impetus“Philoponus compares this impetus or ‘incorporeal motive 
enérgeia’, as he calls it, to the activity earlier attributed to light.
Once projectile motion was understood in terms of an impetus in this way, it became possible for Philoponus to reassess the rôle of the medium: far from being responsible for the continuation of a projectile’s motion it is in fact an impediment to it (In Phys. 681). On this basis Philoponus concludes, against Aristotle, that there is in fact nothing to prevent one from imagining motion taking place through a void.”
subkind of
Enérgeia“Philoponus compares this impetus or ‘incorporeal motive enérgeia, as he calls it, to the activity earlier attributed to light.”

Sources

  • Wildberg, Christian, “John Philoponus”The Stanford Encyclopedia of Philosophy (Winter 2021 Edition, Edward N. Zalta (ed.)
  • SORABJI, RICHARD: “HILOPONUS AND THE REJECTION OF ARISTOTELIAN SCIENCE”, EDITED BY RICHARD SORABJI INSTITUTE OF CLASSICAL STUDIES SCHOOL OF ADVANCED STUDY UNIVERSITY OF LONDON 2010
  • First published: 16/5/2022

[5.0.0] John Philoponus on Light

John Philoponus (490-570 AD) worked out an original theory of light:

  • According to Philoponus colour and light is subkind of energeia.
  • Light manifests directional.

The following OntoUML diagram presents the theory of light

Philoponus on Light

CLASSDESCRIPTIONRELATIONS
Energeia“light it has been said that Philoponus ‘completely rejects’ Aristotle, turning light from a static to a kinetic phenomenon better suited to the needs of geometrical optics, and changing the meaning of Aristotle’s word energeia in the process.
It is an important contribution to have drawn attention to Aristotle’s innovation here, but I am not sure that the innovation has been rightly understood.
We need to distinguish light from the action of colour. Each can be called an energeia. Light is the state in virtue of which a transparent medium can actually be seen through, whereas in the dark the medium is only potentially seeable-through. This is what Aristotle means, as Philoponus sees, when he calls light the actualised state (energeia, entelecheia) of the transparent.”
Colour“There is also an energeia of colour. Philoponus uses the for something that goes on in the medium between the observer agrees that colour acts on the medium, but he prefers to rather than an energeia (activity).
To his kinesis he applies De generatione animalium speaks of the kinesis as ‘arriving’, distant object, and as ‘taking a straight course’ or ‘being scattered’. “
subkind of
LightLight is the state in virtue of which a transparent medium can actually be seen through, whereas in the dark the medium is only potentially seeable-through. This is what Aristotle means, as Philoponus sees, when he calls light the actualised state (energeia, entelecheia) of the transparent.”
Whatever may be the case about colour, it is made emphatically light does not travel in the sense of affecting one part of Light should rather be thought of as a state in virtue of actually seeable-through…”
subkind of
DirectionalWhat I conclude is that Philoponus does indeed change Aristotle’s theory of light to make it directional in the way it needs to be. On the other hand, he does not introduce travel in the sense of a time-taking process. Nor does he overthrow
Aristotle’s theory of the action of colour on the medium. Instead, he gives to light the same directionality as was already to be found in Aristotle’s account of the action of colour.

Sources

  • SORABJI, RICHARD: “HILOPONUS AND THE REJECTION OF ARISTOTELIAN SCIENCE”, EDITED BY RICHARD SORABJI INSTITUTE OF CLASSICAL STUDIES SCHOOL OF ADVANCED STUDY UNIVERSITY OF LONDON 2010
  • Wildberg, Christian, “John Philoponus”The Stanford Encyclopedia of Philosophy (Winter 2021 Edition, Edward N. Zalta (ed.)

First published: 16/5/2022