Full Idea
With their 'mass-noun' ontologies, the early pre-Socratics were blind to plurality ...but the count-noun ontologists came to dominate the field forever after.
Gist of Idea
Early pre-Socratics had a mass-noun ontology, which was replaced by count-nouns
Source
José A. Benardete (Metaphysics: the logical approach [1989], Ch. 6)
Book Reference
Benardete,José A.: 'Metaphysics: The Logical Approach' [OUP 1989], p.36
A Reaction
The mass-nouns are such things as earth, air, fire and water. This is a very interesting historical observation (cited by Laycock). Our obsession with identity seems tied to formal logic. There is a whole other worldview waiting out there.