In the chapter 9,Stephen Hawking advanced the idea that the condition ”no edge” and the weak anthropic principle can explain together why the three arrows point in the same direction.The psychological arrow is determined by the thermodynamic arrow.These two arrows point necessarily in the same direction so that the conditions be acceptable for the development of the intelligent beings who can ask the question : why the disorder grows in the same direction of that which the universe dilates?
For the second principle of thermodynamic arrow,there are always more disordered states than the ordered states.For example,consider the pieces of a puzzle in a box : there is only one arrangement for which the pieces will form a complete picture.On the other side, there are a very large number of arrangements in which the pieces of puzzle can be in disorder and represent nothing.
And this universe is believed by scientists to be in expansion because the american astronomer Edwin Hubble discovered that the more galaxies are distant and pale, the more galaxies move away from us.But in this situation,Stepehn Hawking considered that our universe is in disorder while expanding,just as a water glass fallen from the table and was broken into pieces going in all directions.
We are in the time of disorder(expansion),but if we are in the time of contraction,we can see the pieces of water glass coming back together to form a water glass as it was before being fallen and broken.