I mentioned some time back the Closer to Truth series, in which Robert Lawrence Kuhn chats with scientists, philosophers, and theologians about the Big Questions. Apparently some excerpts are now appearing on YouTube — here I am talking about whether time is real.
In one sense, it’s a silly question. The “reality” of something is only an interesting issue if its a well-defined concept whose actual existence is in question, like Bigfoot or supersymmetry. For concepts like “time,” which are unambiguously part of a useful vocabulary we have for describing the world, talking about “reality” is just a bit of harmless gassing. They may be emergent or fundamental, but they’re definitely there. (Feel free to substitute “free will” for “time” if you like.) Temperature and pressure didn’t stop being real once we understood them as emergent properties of an underlying atomic description.
The question of whether time is fundamental or emergent is, on the other hand, crucially important. I have no idea what the answer is (and neither does anybody else). Modern theories of fundamental physics and cosmology include both possibilities among the respectable proposals.
Note that I haven’t actually watched the above video, and it’s been more than three years since the interview. Let me know if I said anything egregiously wrong. (I’m sure you will.)