  The source of entropic asymmetry is sought, rather, in the physical state of the world at the Big Bang. Matter “just after” the Big Bang is usually posited to be in a state of maximum entropy – to be in thermal equilibrium. But this does not take account of the structure of “space itself,” or, if you wish, of the way in which the matter is distributed in space and subject to the universal gravitational attraction of all matter for all other matter. A world in which matter is distributed with uniformity is one of low entropy. A high entropy state is one in which we find a clustering of matter into dense regions with lots of empty space separating these regions. This deviation from the usual expectation – spatial uniformity as the state of highest entropy – is due to the fact that gravity, unlike the forces governing the interaction of molecules in a gas for example, is a purely attractive force.