In Chapter 1, we surveyed the experimental and observational situation in cosmology and proposed five principles which we believe must constrain the construction of any properly cosmological theory:

1. The principle of differential sufficient reason.

2. The principle of the identity of the indiscernible.

3. Explanatory closure.

4. No unreciprocated action.

5. Falsifiability and strong confirmability.

Having set the scene, we now propose three hypotheses which we suggest should guide the discovery of a cosmological theory which satisfies these principles. I will state the hypotheses and then discuss each in turn.

1. The uniqueness of the universe.

2. The reality of time.

3. Mathematics as the study of systems of evoked relationships, inspired by observations of nature.

Someone might call these also principles, but I want to stress that the first two are hypotheses about nature, which might be confirmed or disconfirmed as science progresses. They have force because they suggest different kinds of experiments and different results than approaches which deny them or embrace hypotheses which conflict with them.

Now I elaborate on each of these.