philosophy of sciencephysicstime
Why does time have a direction when the underlying laws do not? Carroll’s answer runs through entropy and cosmology: the arrow we experience is not built into the equations but inherited from the extraordinarily low-entropy state the early universe happened to be in — which pushes the question back to why the past was ordered at all.
His own proposal with Jennifer Chen has universes budding off an empty, eternal de Sitter background, each carrying its own arrow. Whether or not that survives, the book is a careful demonstration of how much of ordinary experience — memory, cause preceding effect, the felt passage of time — turns out to rest on a statistical fact about initial conditions.
