Hallucination, Virtual Reality, and Reality

Some consider virtual reality to be akin to mere hallucination, whereas others see it as potentially on a par with physical reality. Both seem possible to me (depending on the precise nature of the VR we're imagining), so let's try to clarify matters by drawing some distinctions. First, we can consider the epistemic dimension of whether you remain aware (on some level) that you're in a virtual world, or if the VR is all-consuming. More importantly, I think we can identify variation along a metaphysical dimension of sorts, as per the following three alternatives:

(1) Passive Experience Machine: You are passively fed an externally determined 'phenomenal soup' (including the phenomenal experience as of making certain decisions), effectively living out someone else's story from the inside.

(2) Active Solipsism: A genuinely interactive fiction, where you make decisions that affect how things turn out. But you are the only sentient being immersed in the world -- any others you "see" are mere simulacra (or 'Non-Player Characters', in geekspeak).

(3) Active Shared Virtual Worlds: In this final category, the virtual world serves as a medium for causally interacting with other people, as in The Matrix.

When it comes to assessing a life spent immersed in such VR, I think these differences are of immense normative significance. The Passive Experience Machine is indeed akin to an extended hallucination, and a life so bereft of agency may strike many of us as no life at all. The case of Active Solipsism is at least some improvement on this, though still abhorrent insofar as we are social animals who value genuine relationships, and see them as grounding much of the meaning in our lives.

What about the final option: Active Shared VR? In principle (i.e. if the VR faithfully reproduced all the multi-modal sensory richness and fine-grained environmental responsiveness that physical reality has to offer), I think that such a world must be acknowledged as no less 'real' - in any sense that matters - than our own. It seems a piece of metaphysical chauvinism to claim otherwise: to think that when lovers intentionally cause mutual sensations of kissing this only counts as really kissing when there aren't any bits or bytes (but only atoms serving in a non-computational capacity) in the causal chain. (Compare the absurdity of claiming that people on the phone aren't really talking to each other, but merely "simulating" talking.) What's so special about material reality? It only matters insofar as it provides a common causal medium for the interaction of minds against a stable backdrop; but any other equally-responsive and stable medium could fill this role just as well -- its intrinsic nature, as material or computational, cannot plausibly be thought to matter.

'Reality' is just the stable causal backdrop for interacting minds. As such, it is multiply-realizable. Material stuff can do the job of reality, as can computational bits and bytes (at least in principle), or we could even have a kind of Berkeleyan Idealism according to which our existence is fundamentally based in the mind of God. So long as the requisite stability and mutual (counterfactual-supporting) causal influence obtains, the fundamental grounds don't matter. Our everyday concepts, and hence the contents of our desires, typically concern the surface structure of reality (that which the materialist and idealist worlds have in common), not its fundamental nature. So this is not a difference that would make a difference, so far as most of us are concerned.

(N.B. It would make a difference if the causal structure mediating our experiences were to be excised or impaired. I'm no subjectivist: a world where people have no causal impact on each other's experiences is a world that's sorely lacking.)

So, I agree with Alexandre Erler that "there is an important difference between my actually going to see the pyramids of Egypt, or having sex, and my sitting alone in my house in an armchair with electrodes plugged into my brain... believing I am doing these things." But then, there's also an important difference between merely believing that you're doing these things, and actually doing them in a different medium. This distinction is occluded if we fail to carefully distinguish the different forms that a 'Virtual Reality' could take.