Full Idea
Speusippus suggested principles for each substance, including principles for numbers, magnitude and the soul. He thus arrived at no mean list of substances.
Gist of Idea
Speusippus suggested underlying principles for every substance, and ended with a huge list
Source
report of Speussipus (thirty titles (lost) [c.367 BCE]) by Aristotle - Metaphysics 1028b
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.171