Full Idea
To be an A-theorist is to believe in some sort of objective distinction between what is present and past and future. ..To be a B-theorist is to deny the objectivity of our talk about past, present and future.
Gist of Idea
A-theorists, unlike B-theorists, believe some sort of objective distinction between past, present and future
Source
Dean W. Zimmerman (The Privileged Present: A-Theory [2008], 2)
Book Reference
'Contemporary Debates in Metaphysics', ed/tr. Sider/Hawthorne/Zimmerman [Blackwell 2008], p.212
A Reaction
The A/B distinction originates with McTaggart. All my intuitions side with the A-theory, certainly to the extent that the present seems to be objectively privileged in some way (despite special relativity).