Glossary
The Perfect Cosmological Principle

The Perfect Cosmological Principle is an extension of the Copernican Cosmological Principle and is that not only
on a large scale, the universe is both homogeneous and isotropic,

but also that
the universe presents a similar aspect when viewed from any point in space AND time.


Rationale/Implications

The Perfect Cosmological Principle(s) is very attractive/useful from a philosophical point of view. It removes the necessity for having to deal with the birth/death of universe (and the corresponding philosophical issues of what happened before, what caused the birth, etc). The Universe is and has always been.

This principle is a fundamental assumption of the Steady-State Cosmological Theory.

This principle therefore takes the opposite view of the Anthropic Cosmological Principle(s)


An Analogy

A (small) sentient being living in the center of a "perfect" loaf of bread.
  • There may be obvious structure on small scales (air bubbles etc), but on the large scale the loaf can be considered uniform and isotropic
  • The laws of physics (e.g. which caused the dough to rise) are the same throughout the loaf.
  • However, contrary to the case for the Copernican Cosmological Principle the loaf has always (& will always) exist with the same characteristics as a function of time.
    • So if the loaf appears still be rising, (which in this perfect loaf) this happens uniformly & following the same laws throughout the loaf), then the density of the loaf must remain constant, thus bread-particles must spontaneously appear to compensate for the expansion.