  Two of the most difficult problems in the foundations of physics are (1) what
gives rise to the arrow of time and (2) what the ontology of quantum mechanics
is. I propose a unified 'Humean' solution to the two problems. Humeanism allows
us to incorporate the Past Hypothesis and the Statistical Postulate into the
best system, which we then use to simplify the quantum state of the universe.
This enables us to confer the nomological status to the quantum state in a way
that adds no significant complexity to the best system and solves the
"supervenient-kind problem" facing the original version of the Past Hypothesis.
We call the resultant theory the Humean unification. It provides a unified
explanation of time asymmetry and quantum entanglement. On this theory, what
gives rise to time's arrow is also responsible for quantum phenomena. The new
theory has a separable mosaic, a best system that is simple and non-vague, less
tension between quantum mechanics and special relativity, and a higher degree
of theoretical and dynamical unity. The Humean unification leads to new
insights that can be useful to Humeans and non-Humeans alike.
