Gruber and Smith (2019) have conducted some interesting virtual reality (VR) experiments, but we think that these experiments fail to illuminate why people think that the present is special. Their experiments attempted to test a suggestion by Hartle (2005) that with VR one might construct scenarios in which people experience the same present twice. If that’s possible, then it could give us a reason to think that when we experience the present as being special, that’s not because it’s objectively so. (...) Instead, our experience of the present being special is a feature of having a psychology like ours. While we are sympathetic to the thought that there is no objective present, we do not think that these experiments give us a reason to think this. That said, VR experiments, such as Gruber and Smith’s, hold much promise for being able to illuminate various aspects of our temporal psychology.According to Hartle’s (2005) IGUS model (which is meant to resemble entities like us) sensory information is routed to two kinds of processes: conscious processes C, which cause behavior, and unconscious processes, U, which construct a schematic representation of the environment. Hartle proposed that we experience the present as being special because of the sensory information at a time entering into C. For Gruber et al. (2020), the succession of sensory information entering into C underpins our experience of time passing. Our experience of time passing is illusory because it fails to be verid... (shrink)

Gruber et al. (2022) and Buonomano and Rovelli (Forthcoming) aim to render Q18 consistent the picture of time delivered to us by physics, with the way time seems to us in experience. Their general approach is similar; they take the picture of our world given to us in physics, a picture on which there is no global “moving” present and hence no robust temporal flow, and attempt to explain why things nevertheless seem to us as they do, given that our (...) world is that way. In this, they follow in the footsteps of Hartle (2005), Callender (2017), and Ismael (2017), who argue that any information gathering system (an IGUS) will, in learning to navigate our world, represent the distinctions between past, present, and future, and represent their own changing trajectory through spacetime. While we are generally very sympathetic to this approach, there are several places where we disagree. (shrink)

Why is our knowledge of the past so much more ‘expansive’ (to pick a suitably vague term) than our knowledge of the future, and what is the best way to capture the difference(s) (i.e., in what sense is knowledge of the past more ‘expansive’)? One could reasonably approach these questions by giving necessary conditions for different kinds of knowledge, and showing how some were satisfied by certain propositions about the past, and not by corresponding propositions about the future. I take (...) it that such is the approach of Chapter 6 of Time and Chance (T&C). Here’s another such a proposal, similar to that of, but significantly different from T&C; my purpose in this section is to highlight the differences, by showing how this account fails. (shrink)