Full Idea
Presentists deny that everything is instantaneous; they think that many objects not only exist, but also have existed and will exist.
Gist of Idea
Presentists say that things have existed and will exist, not that they are instantaneous
Source
Trenton Merricks (Truth and Ontology [2007], 6.I)
Book Reference
Merricks,Trenton: 'Truth and Ontology' [OUP 2007], p.124
A Reaction
The second half is because presentists are committed to the truth of tensed existence claims (despite a lack of any theory as to how they work). Does anyone hold a theory of Instantaneousism?