This appears to me the most attractive of the three options. A first attempt at an argument proceeds as follows. In Case A, Fonda recognizes (say) that the color of the sky in the simulation is the same as the color of grass in the outside world (i.e., green), whereas it could just as well have been displayed as the color of the sky in the outside world (i.e., blue). That is, the correspondence between colors in the simulation (as displayed on the screen) and colors in the outside world clearly could have been different, without the code that governs the laws of physics and the initial conditions in the simulation being any different. Thus there is clearly a “further fact” present, consisting in the additional code that governs how a perspective is displayed on the monitor. In Case B, however, Fonda cannot recognize the existence of any such correspondence, because she no longer remembers the outside world. Hence—so the argument goes—she cannot conclude further facts exist.
Now, this argument does not seem entirely satisfactory to me. Even in Case B, it seems entirely possible for Fonda to imagine a scenario where the color of the sky (in the simulation, though she does not know it is a simulation) would be the color that the grass is now (in the simulation), and vice versa. This is the familiar inverted spectrum scenario, except in this case, by virtue of all this taking place in a virtual reality system, it is clearly true that the spectrum could be inverted; all this would require is some changes to the code governing the display. Nevertheless, it is still possible that Fonda’s belief that the spectrum could have been inverted is not justified. Having forgotten about the outside world, she certainly does not know about the simple mechanism—changing a few lines of code in the outside world—by which the spectrum could indeed be inverted. But few would argue that awareness of a specific mechanism by which the spectrum could be inverted is necessary to justify belief in the possibility of an inverted spectrum (though it is clearly sufficient).
Nevertheless, it seems that the physicalist, arguing that Fonda’s belief is not justified, has arguments available in Case B that are unavailable in Case A. The physicalist can argue that Fonda cannot be sure that experiential properties corresponding to her seeing the simulated sky are not, at bottom, physical properties. (Again, here, “physical” refers to the physics of the environment, which we happen to know is simulated but she does not.) Even in our own case (Case C), fleshing out such an argument and addressing immediate counterarguments requires substantial work; see, for example, Hawthorne (2002). But I do not see that any additional obstacles to such an argument are introduced when moving from Case C to Case B. In contrast, in Case A such an argument becomes untenable. In that case, Fonda clearly knows that the experiential properties corresponding to her seeing the simulated sky are not, at bottom, properties of the simulated physics; she knows that the code governing the display, the monitor itself, her eyes and brain, etc., are also involved.
So, perhaps this all reduces to standard arguments about inverted spectra. Perhaps Fonda cannot reasonably reject the possibility that the way colors appear to her necessarily emerges from the laws of her universe. If so, it at least suggests that the debate on inverted spectra has been on the right track. But it also provides a clearer lens on these arguments.Footnote 13 This is because unlike in the standard inverted spectrum scenario, in this case it is clearly true that the spectrum could have been inverted. This, I believe, reduces the intuitive appeal of the argument that which quale appears must supervene upon properties of the physical world (and that therefore a strong type of inverted spectrum is not possible). It makes it clear that if this argument is to succeed, it should be fundamentally epistemological in nature: it should argue just that we cannot know that there is no such supervenience. At least, this is so if our epistemic situation is sufficiently like that of Fonda in Case B, and it appears that it is, as discussed in the previous section.
It is useful to note that even slightly nudging Case B towards Case A—for example, allowing Fonda to remember only that she is in a simulation, but effectively nothing else about the outside world, including even whether her color experiences there were anything like the ones she is experiencing now—would again allow her to soundly conclude that an inverted spectrum in her simulated world is a genuine possibility. This is why it is important to be strict about Fonda not remembering anything in Case B.
Next, let us consider further facts about personal identity and the self. Again, in Case A, Fonda can soundly conclude that there are further facts about how the perspectives of agents in the simulation are assigned to monitors in the outside world. Even if every agent’s perspective is displayed on some monitor, clearly the correspondence—on which particular monitor each agent’s perspective is displayed—could have been different, without the code that governs the laws of physics and the initial conditions of the simulation being any different. Thus there is clearly a further fact present, consisting in the additional code that governs on which (if any) monitors each perspective is displayed. Again, however, in Case B, Fonda cannot recognize the existence of any such correspondence, because she no longer remembers the outside world. So one might argue that in Case B she is not justified in believing in the existence of further facts about personal identity and the self.
How satisfying is this argument? Could she nevertheless, in Case B, imagine the perspective of an agent other than Alpha appearing to her? Certainly it is true that a different agent’s perspective could be made to appear to her; all this would require is a change to the code governing which perspective is displayed by the VR system. But would she be justified in believing that a different perspective could have appeared to her? Again, it seems that the moment we allow her to remember even just the mere fact that she is in a simulation, even if she remembers nothing else about her identity in the outside world, she can indeed conclude that a different agent’s perspective could have been made to appear to her. But we explicitly rule out such a memory in Case B. Hence, it is not clear that the notion of a different perspective appearing to her makes sense from Fonda’s perspective. For all she knows, she is Alpha, and how could any perspective other than Alpha’s appear to Alpha?
It is interesting to note that this argument is not entirely analogous to the corresponding argument regarding color appearance given earlier. It may be plausible to Fonda that the way colors appear necessarily emerges from the laws of the universe in which she finds herself. But it seems implausible that somehow Alpha’s perspective, to the exclusion of any other, necessarily emerges as the “present” one from these laws, given that Alpha is just one agent among many similar ones as far as these laws go.Footnote 14 Instead, the argument here relies on the possibility of her complete identification with Alpha.
Again, perhaps this all reduces to standard arguments about personal identity and the self. If so, then again, this on the one hand suggests that the debate has been on the right track, while on the other hand also casting a clearer lens on it. This is because unlike in standard scenarios in the literature on personal identity and the self, here it is clearly true that Fonda “could have been someone else”—i.e., she could have had a different agent’s perspective in the simulation displayed to her on the VR system. This highlights, again, that the problem fundamentally has an important epistemological component.