As a poster said, the fitness filter may as well be "whatever works" in the sense that it's so rare to stumble upon stable combinations of energy, space and tim

As a poster said, the fitness filter may as well be "whatever works" in the sense that it's so rare to stumble upon stable combinations of energy, space and time (if they are at all separate concepts) that whatever works, continues existing, and if circumstances allow, spreads. It's actually quite a neat concept, if very similar to the anthropic principle. Unfortunately, it offers no predictions.