The goal of the Wolfram Physics Project is to find a rule that generates our Universe, as it was envisioned in the section Ultimate Models for the Universe of the chapter Fundamental Physics of S. Wolfram's book A New Kind of Science. The main obstacle is that the evolution of our Universe may be computationally irreducible. If this is the case, the emergent properties generated by the rules from the candidates of the Wolfram Model of our Universe can only be obtained by means of extremely slow simulations.
One way to overcome the problem of computational irreducibility is to construct the Wolfram Model of our Universe in a time-reversal way, using the forms of matter from the previous epochs of the Universe as black boxes. In the chronology of our Universe, we have the following epochs (in chronological order):
One way to progress in the Wolfram Physics Project is to develop a Wolfram Model in order to explain the transition from any cosmological epoch to the next one. For example, we could imagine papers with titles like "A Wolfram Model for the transition from the Quark epoch to the Hadron epoch". Finally, after recreating the history of our Universe by means of Wolfram Models of transitions between two consecutive epochs, the next challenge will be to write a paper with the title "A Wolfram Model for the time before the Planck epoch".