Full Idea
Objects of mathematics abstract from perceived matter both in particular and in general, though from thought matter (substance as underlying quality) only in particular and not in general.
Gist of Idea
Mathematical objects abstract both from perceived matter, and from particular substance
Source
Thomas Aquinas (Summa Theologicae [1265], Ch.5 Q85.1)
Book Reference
Aquinas,Thomas: 'Summa Theologicae (Concise)', ed/tr. McDermott,Timothy [Christian Classics 1991], p.133
A Reaction
This appears to be a thoroughly abstractionist view of the way in which humans create mathematics. Aquinas explicitly denies the Platonic view that the numbers already have abstract existence, awaiting our discovery.