Gerard 't Hooft. Free Will in the Theory of EverythingDemand # 1: Our rules must be unambiguous. At every instant, the rules lead to one single, unambiguous prescription as to what will happen next.
Demand # 2: We must have causality: every event must have a cause, and these causes all must lie in the past, not in the future.
Demand # 3: Efficiency Not all events in the past, but only a few of them should dictate an event in the presence.
Rule #1: Locality. All configurations one needs to know to determine the behaviour of an object at a given spot, must be lying in its vicinity.
Rule #2: Velocity. Any object for which it has been decided how it behaves when at rest, will behave very similarly when it moves along a straight line in any direction, with any constant velocity (within limits, see the next rule).
Rule #3: There is a speed limit. Call it c, the speed of light.
Rule #3a: Things that go very fast, will have time going slower.
Rule #3b: Things that go very fast, will also contract in the forward direction.
Rule #3c: Inside things that move fast, clocks will no longer go synchronously.
Rule #4: Matter is quantised. The smallest quanta of matter are the elementary particles.
Rule #5: Forces. If it is known how an object behaves while moving on a straight line with constant velocity, it should be possible to deduce how it behaves moving with a varying velocity on a curved line.
Rule #6: God must tell his computer what the initial state is.
Rule #7: Combine all these rules into one computer program to calculate how this universe evolves.
