Reality+: Virtual Worlds and the Problems of Philosophy

by David J. Chalmers

I wouldn’t say we can know we’re in a simulation; there are too many possible sim blockers to be sure of that. I can’t know for sure that humanlike simulations are possible. Perhaps consciousness is substrate-dependent, or physical processes are uncomputable. And I can’t know for sure that if these simulations are possible, humanlike populations will create them. Perhaps almost all of them will go extinct or avoid simulations. So I can’t know for sure that most humanlike beings are simulated, and I can’t be confident that we’re sims.

I don’t think we can be at all confident that there are sim blockers. If I had to estimate, I’d say it’s more likely than not that consci...

I’d also say it’s more likely than not that if conscious humanlike simulations are possible, many humanlik...

If so, then there’s less than a 50 percent chance that there are sim blockers in the first class, and less than a 50 percent chance that there are sim blockers in the second class. It follows (given plausible assumptions) that there is less than a 75 percent chance that there are any sim blockers at all. Given that it’s at least 99 percent likely that either there are sim ...

Whatever one says about the probabilities, this argument suggests very strongly that we can’t kno...

We can be highly confident that either we are sims, or that most humanlike populations won’t create humanlike sims, or t...

An opponent might suggest that we can know we’re not in a simulation by one of the methods discussed earlier—Bertrand Russell’s appeal to simplicity, say, or G. E. Moore’s observation of his own hands—and that we could thereby conclude that one of the sim blockers obtains, although we can’t be sure which.

The simulation argument does something similar. It elevates the simulation hypothesis to the status of a serious possibility to which we should assign substantial probability. Whether that probability is 20 percent or 50 percent, the anti-skeptical arguments we’ve discussed do not drag it down. Once it is a serious possibility that we’re in a simulation, none of these arguments allows us to know that we’re not. I conclude that we cannot know that we are not in a simulation.

“Reality is the only thing that’s real.” At first, this looks like a tautology, akin to Boys are boys. Of course only reality is real! On second glance, it looks like a confusion, as with Happiness is happy. How could reality itself be real?

the underlying message is pretty clear. In the context of the movie, the speaker is praising physical reality and downgrading virtual reality. The intended message: Physical reality is the only thing that’s real. And Virtual reality is not real.

What is it for physical or virtual realit...

On my reading, the central idea is that a reality is real if things in ...

Read this way, the slogan is saying Physical things are the only things that are real, and V...

If the slogan is right, the planet Earth is real, whereas the planet Ludus (a virtual planet in Ready Player One) is not. Earth and the things on it, from ducks to mountains, exist as part of the objective world. Ludus and the things on it, from ava...

Virtual things are not real is the standard line on...

Virtual reality is real—that is, the entities in virtual re...

virtual r...

Heim associated the label with the view that “Virtual entities are indeed real, functional, and even central to life in coming eras.”

As I understand it, virtual realism is the thesis that virtual reality is genuine reality, with emphasis especially on the view that virtual objects are real and not an illusion. In general, “realism” is the word philosophers use for the view that something is real.

Someone who thinks morality is real is a moral realist. Someone who thinks that colors are real is a color realist. By analogy, someone who believes that virtual objects are real is a virtual realist.

I also accept simulation realism: If we’re in a simulation, the objects around us are...

Simulation realism says that even if we’ve lived our whole life in a simulation, the cats and chairs in the world around us really exist.

They aren’t illusions;

the Cartesian path to global skepticism says no to the Reality Question (in a simulation, nothing is real) and says no to the Knowledge Question (we can’t know we’re not in a simulation). When we accept simulation realism, we say yes to the Reality Question. In a simulation, things are real and not illusions. If so, the simulation hypothesis and related scenarios no longer pose a global threat to our knowledge. Even if we don’t know whether or not we’re in a simulation, we can still know many things about the external world. Of course, if we’re in a simulation, the trees and cars and Beyoncé are not exactly how we thought they were. Deep down, there are some differences. We thought that trees and cars and human bodies were ultimately made of fundamental particles such as atoms and quarks; instead, they’re made of bits.

virtual digitalism.

Virtual digitalism says that objects in virtual reality are digital objects—roughly speaking, structures ...

Virtual digitalism is a version of virtual realism, since digital objects are perfectly real. Structures of bits are grounded in real processing, in a real computer. If we’re in a simulation, the computer is in the next world up, metaphorically speaking. But the digital objects are no less real for that. So if w...

Before defining real, I’ll say something about defining reality. This word has at least three meanings that are relevant for our purposes.

First, when we talk about reality as an entity, we mean something like everything that exists: the entire cosmos.

When we talk about physical reality and virtual reality as entities, we mean something in the same spirit. We mean roughly everything that’s ...

Second, when we talk about a reality, we mean something like a world. When we talk about realities plural, we mean worlds. When we talk about a virtual reality, we mean roughly a virtual world. A world is roughly equivalent to a ...

Reality (in the first sense) may contain many realities (in...

In a multiverse, reality contains many worlds and many realities. With the advent of virtual worlds, we have Reality+: a multiverse of both physical and virtual realities. All of these realities (worlds) are part of reality (the cosmos).

Third, we can talk about reality as a property like rigidity. Rigidity is the property of being rigid. Some objects are rigid, and some are not. In this sense, reality is real-ness. It’s the property of being real. Some things are real, and others are not. Talking about reality as real-ness is a way of talking about what it is to be real. That’s our focus in this chapter.

reality contains many realities, and those realities are real.

the cosmos (everything that exists) contains many worlds (physical and virtual spaces), and the objects in those worlds are real. Now we just need to unpack real.

Morpheus asks, “What is real? How do you define real?”

Reality as existence.

something is real if it really exists.

Santa Claus doesn’t really exist; he’s not part of the universe. There are stories about Santa Claus, and there are beliefs about Santa Claus, but Santa Claus himself does not exist.

perhaps not in this universe

“What is it to exist?”

Recall Berkeley’s dictum from chapter 4: esse is percipi. To be is to be perceived—which means that something exists if it’s perceived or at least could be perceived.

As Morpheus put it, when we say something is “real,” we might be talking about “what you can feel, what you can smell, what you can taste and see.”

A related, more scientific-sounding view is that something is real i...

There could be real things that we can never perceive and never measure. It may be that we can never measure certain physical entities around the time of the Big Bang, or in distant galaxies, but they exist all the same. If I’m in a perfect simulation, I may never be able to perceive the world outside the simulation, but it’s real all the same. There are also some things we can perceive and measure that aren’t real. We can measure the intensity of a mirage, for example, but this doesn’t mean the mirage really exists.

maybe not in this universe

Still, Berkeley’s dictum can function well as a heuristic for existence—that is, an imperfect guide to what exists—rather than an absolute criterion. If something is perceivable and measurable, that’s a strong indication that it exists.

Reality as causa...

sub...

Eleatic d...

“I suggest that everything which possesses any power of any kind, either to produce a change in anything of any nature or to be affected even in the least degree by the slightest cause, though it be only on one occasion, has real being.”