Here we set up the problems in physics that we would like to solve and outline our approach.
One key technique we will use is that we imagine ourselves to be outside of the world and looking in. Observing a system from within can sometimes appear very different to viewing it from outside.
An excellent example is how we view the solar system. The most natural view is to take the earth to be flat and stationary and to assume that the sun and planets move around it, as people must have thought for 10000s of years.
Here an observer looks at a sunrise. The world appears to be flat. The sun and stars appear to move around it in circular orbits, but some of the planets sometimes follow strange paths in the sky. It is very hard to account for their trajectories.
The observer proposes a new theory, that contradicts the assumption that the concepts of ‘up’ and ‘down’ are absolute, i.e. the same direction everywhere in the world. The major paradigm shift is to imagine being outside of the world looking in.
Here the observer imagines himself to be floating in space and looking down at a solar system from the outside. He doesn’t need a spacesuit, as this is just a thought experiment.
He has imagined a sun to be in the centre and some large spheres to move around it. This is not hard to do, but the big mental leap is to imagine what it then looks like, living on the surface of one of those spheres.
The observer realises that the surface of the sphere would appear flat, provided that it is large enough, and that the sun and stars would appear to move around the sphere. So far this view of the world is equivalent to the old geocentric one, but the crucial factor that convinces him that his new idea is better are the paths of the other planets in the sky. In the new theory they are explained easily, they are a natural consequence of the new, heliocentric, point of view. In the old theory the paths of the planets are not explained, but require arbitrary empirically determined rules.
Here we use the same technique and imagine a world with not just one, but multiple time dimensions, and imagine how it would feel to live inside it.