Full Idea
'Perdurantism' is the view that objects persist by being composed of temporal parts. When it is commonly combined with the eternalist account of the ontology of time, the result is known as 'four-dimensionalism'.
Gist of Idea
Four-Dimensional is Perdurantism (temporal parts), plus Eternalism
Source
Neil E. Williams (The Powers Metaphysics [2019], 08.1)
Book Reference
Williams,Neil E.: 'The Powers Metaphysics' [OUP 2019], p.175
A Reaction
At last, a clear account of the distinction between these two! They're both wrong. He says the result is the spatiotemporal 'worm' view (i.e. one temporal extended thing, rather than a collection of parts).