[Jweb_Guru]

The problem, I suspect, is that there isn't really one formal "actor" model that everyone agrees on. People have used it to describe formal models like CSP and linear logic, practical systems like the Erlang VM and Go's green threading implementation, and capability-based systems like the (provably secure) SEL4; these are not the same thing. And, not to pick on you specifically, this is exacerbated by confusingly referring to "promises, futures, and async" as "paradigms." Promises and futures are for the most part identical, and I don't see how you can meaningfully call them "paradigms"--they're just APIs. "Async" (async what?) is maybe abstract enough that I'd be willing to call it a "paradigm," but I don't see how actors don't also fall into that category.

[felixgallo]

could you point to a place where anyone's said that Go, or any other CSP system, are Actor systems? That would be interesting to see.

Promises and futures are not actually identical; and they're paradigms, because they are concepts shared across a large number of different languages. 'Async' is the P in CSP, as in C# (called 'async'), and as in ES7 (https://github.com/lukehoban/ecmascript-asyncawait). Hope this helps you.