"Many cosmologists have tried to attribute the time asymmetry to the process of cosmological inflation. Inflation is an attractive explanation for many basic features of the universe. According to this idea, the very early universe (or at least some part of it) was filled not with particles but rather with a temporary form of dark energy, whose density was enormously higher than the dark energy we observe today. This energy caused the expansion of the universe to accelerate at a fantastic rate, after which it decayed into matter and radiation, leaving behind a tiny wisp of dark energy that is becoming relevant again today. The rest of the story of the big bang, from the smooth primordial gas to galaxies and beyond, simply follows.

The original motivation for inflation was to provide a robust explanation for the finely tuned conditions in the early universe - in particular, the remarkably uniform density of matter in widely separated regions. The acceleration driven by the temporary dark energy smooths out the universe almost perfectly. The prior distribution of matter and energy is irrelevant; once inflation starts, it removes any traces of the preexisting conditions, leaving us with a hot, dense, smooth early universe."

I previously argued that the origin of time asymmetry is to be sought in the processes that characterized the very early cosmological epochs, and that the recent inflationary scenario provides a crucial element in our understanding of this origin1. Here, I develop this thesis further, in the light of criticisms by Page2. I argue in particular that any of the "initial states" that appear to be permitted by quantum gravity, if succeeded by a period of inflation, would have wound up the universe to the state from which, as indicated by increasing entropy, it is now winding down.