Sean Carroll in Preposterous Universe:
The arrow of time — all the ways in which the past differs from the future — is a fascinating subject because it connects everyday phenomena (memory, aging, cause and effect) to deep questions in physics and philosophy. At its heart is the fact that entropy increases over time, which in turn can be traced to special conditions in the early universe. David Wallace is one of the world’s leading philosophers working on the foundations of physics, including space and time as well as quantum mechanics. We talk about how increasing entropy gives rise to the arrow of time, and what it is about the early universe that makes this happen. Then we cannot help but connecting this story to features of the Many-Worlds (Everett) interpretation of quantum mechanics.