Abstract
Our time-asymmetric intuitions make it difficult to be objective when considering the nature of time. But these difficulties can be overcome by using the framework of the "block universe", where every event is mapped onto a static, four-dimensional structure. In this perspective, time is represented as a spatial dimension, so the block universe can never "change"; there is no additional time dimension for such a concept to even make sense.
This essay argues that the block universe is by far the best framework for physical theories, as general relativity is simply incompatible with any alternative. The only part of physics that does not fit into such a "block" picture is quantum theory, as it was not originally developed in a block-universe framework. But far from implying that the block universe is incorrect, I argue that we can instead use lessons from the block universe to reconstruct quantum theory in a manner compatible with general relativity.
The essay then outlines how this might be accomplished. A block-universe quantum wavefunction must be represented in four-dimensional space-time, so the usual higher-dimensional "configuration space" is critically examined. The block universe view reveals that the extra information encoded in these higher dimensions is not actually needed, because all possible measurements do not occur on any given system. The need to "discard" the excess information in turn implies that every quantum system must solve a four-dimensional boundary value problem. Interestingly, this is also an approach that solves other outstanding interpretational problems from quantum theory, including the "collapse" of the wavefunction. Taking this research path would require a radical revision of nearly all aspects of quantum theory, but also promises to reshape our understanding of the nature of time.
Ken Wharton