Full Idea
The enquiries of the pre-Socratic philosophers were really into the principles, elements and causes of substance.
Gist of Idea
The Pre-Socratics were studying the principles, elements and causes of substance
Source
Aristotle (Metaphysics [c.324 BCE], 1069a20)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.356