Full Idea
There are two main forms of actualism: reductionism, which seeks to construct possible worlds out of some more mundane material; and moderate realism, in which the actual concrete world is contrasted with abstract, but none the less real, possible worlds.
Gist of Idea
Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions)
Source
Stephen Read (Thinking About Logic [1995], Ch.4)
Book Reference
Read,Stephen: 'Thinking About Logic' [OUP 1995], p.106
A Reaction
I am a reductionist, as I do not take abstractions to be 'real' (precisely because they have been 'abstracted' from the things that are real). I think I will call myself a 'scientific modalist' - we build worlds from possibilities, discovered by science.