Full Idea
If a doctor were to have a theoretical account without experience, knowing the universal but not the immediate particular, he will often err in treatment.
Clarification
'Universals' are general concepts that can refer to many particulars
Gist of Idea
It is not much help if a doctor knows about universals but not the immediate particular
Source
Aristotle (Metaphysics [c.324 BCE], 0981a25)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.5
A Reaction
But acquaintance with particulars isn't the same as knowledge, which may require universals.