Full Idea
In that which underlies a change there is a factor corresponding to the definition [logon] and there is a material factor. When a change is in these constitutive factors there is coming to be or passing away, but in a thing's qualities it is alteration.
Gist of Idea
True change is in a thing's logos or its matter, not in its qualities
Source
Aristotle (Coming-to-be and Passing-away (Gen/Corr) [c.335 BCE], 317a24)
Book Reference
Aristotle: 'The Basic Works of Aristotle', ed/tr. McKeon,Richard [Modern Library Classics 2001], p.478
A Reaction
This seems to be a key summary of Aristotle's account of change, in the context of his hylomorphism (form-plus-matter). The logos is the account of the thing, which seems to be the definition, which seems to give the form (principle or structure).
Related Idea
Idea 16101 A change in qualities is mere alteration, not true change [Aristotle]