The Prospect has a good article here on Parmenides (no longer free).  Stanford’s page here.

“By these arguments, Parmenides arrives at his picture of the world as a single, undifferentiated, unchanging unity. Needless to say, scholars have disagreed over exactly what he meant. They have questioned whether he meant that the universe was one thing, or only that it was undifferentiated.”

Here is a quote from this abstract:

“According to Hume, the idea of a persisting, self-identical object, distinct from our impressions of it, and the idea of a duration of time, the mere passage of time without change, are mutually supporting “fictions”. Each rests upon a “mistake”, the commingling of “qualities of the imagination” or “impressions of reflection” with “external” impressions (perceptions), and, strictly speaking, we are conceptually and epistemically entitled to neither.“

and also:

“Unlike Hume, however, he (Kant) undertakes to establish the legitimacy or objective validity of the schematized category of substance and, correspondingly, of the representation of time as a formal unity with duration as one of its modes.“

Photo found here.