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 propert... (shrink)

In his Commentary on Ptolemy’s Harmonics, Porphyry debunks Ptolemy’s quantitative theory of pitches by demonstrating that pitches are qualitative attributes of sound. I argue that Porphyry’s main concern is to save the phenomenological dimension of sound while preserving the possibility of a quantitative analysis of music. I show how he draws on the Aristotelian tradition to develop a theory of pitches as emergent properties that covary with some underlying quantitative features without being reducible to them. Porphyry offers an original and (...) compelling solution to the classic problem of how to provide a quantitative analysis of a qualitative phenomenon. (shrink)