The Syndicated Actor Model started off (see dissertation) without any notion of object or actor or entity reference at all. Actors inhabited a single dataspace and there was no baked-in addressing. Since then various developments have led to introduction of entity references (like object references in E). Taken together with dataspaces, this gives you several ways of introducing spacelike separation: you can use different message shapes+patterns, like in "classic" Syndicate or like in tuplespaces; you can use entity-references to have multiple dataspaces on the go at once, forcing isolation that way; or some combination of the two.