John of Jandun on Relations and Cambridge Changes^†

† A version of this paper was presented at the XXth European Symposium on Medieval Logic and Semantics held in Cambridge in 2014. I am very grateful for the discussion with Tony Street, Riccardo Strobino, Calvin Normore, Claude Panaccio and Laurent Cesalli.

Abstract

The paradigmatic examples of what we call nowadays ‘mere Cambridge changes’ are relational properties. If someone is on the left of a table at t − 1 and on the right of this table at t, the table does not undergo a physical change, but it has nonetheless new relational properties. What kind of relation lies behind this kind of change? Should we abandon the definition of identity as a set of permanent properties through time? This concern with identity and change was already present in Aristotle's Physics 5 and 7 and medieval commentators tackled the problem with some important refinements due to their metaphysical discussions about the nature of relations. John of Jandun's discussion of this topic, at the beginning of the fourteenth century, is particularly interesting. First, he defines self-identity as a relation of reason, which means for him that it is not a real relation. Second, he distinguishes two kinds of relational changes: those involving real relations and the acquisition a qualitative property; and those that are based on relations of reason. In the second case, there is no real change and the relation is established by the mind. After a presentation of his ontology of relations and changes, we will discuss the application of Jandun's theory to sensation and intellectual knowledge, which he treats as relational changes.

Keywords:

• identity
• Cambridge change
• Aristotle
• John of Jandun

Notes

† A version of this paper was presented at the XXth European Symposium on Medieval Logic and Semantics held in Cambridge in 2014. I am very grateful for the discussion with Tony Street, Riccardo Strobino, Calvin Normore, Claude Panaccio and Laurent Cesalli.

¹For an overview of Greek commentators, cf. Sorabji, The Philosophy of the Commentators, 79–88.

²From this, Peter Geach (‘Identity') concludes that identity is relative. It is possible for objects x and y to be the same F and yet not the same G. In a very interesting essay, David Wiggins has shown that we are not necessarily committed to relative identity. We might continue to accept the logical properties of identity within an Aristotelian theory of natural substance. Cf. Wiggins, Sameness and Substance (Renewed).

³On this distinction, cf. Descombes, ‘La relation’.

⁴His arguments are classical and pretty weak: 1) a relation is distinct from the relata, because when one relatum disappears the relation can continue to exist (a father continues to be a father after his son is dead); 2) two absolute things can be related by a relation which is not reducible to the relata, therefore it is distinct from the relata; 3) if the relation was not distinct from the relata, which are absolute things, then similitude and equality would be one and the same relation.

⁵Some medieval thinkers accept the existence of a contradiction. For an overview of this debate, including Jandun's position, see Knuuttila and Lehtinen, ‘Change and Contradiction'.

⁶It resembles more generation than alteration. See Aristotle, On generation and corruption, I, 4, 319b6–320a5.

⁷Wardy (The Chain of Change) was the first to mention this interpretation, but he finally refused it.

⁸Averroes, Commentarium magnum in Aristotelis De anima libros; In De anima, III, 4, 429a15 sq., com. 3, p. 382, 11 sq.

⁹The fifteenth-century edition has numeratio for mutatio.

¹⁰I would like to thank John Marenbon for the revision of the text and Jean-Baptiste Brenet for his help on Jandun's difficult texts.