[uh_uh]

> It's not just planet-scale, it's universe-scale. Lots of planets conduct the experiment, ours just happens to have resulted in intelligence.

My argument doesn't depend on the existence of an intelligent species on the planet. The problem already arises when there are multiple species on ONE planet. If you calculate the pure combinatorial distance between the DNA of 2 species, you must find that you can't just brute force your way from one to the other before the heat-death of the universe. This is why mutation bias exists: not all mutations are equally likely, evolution favours some kinds over others.

[uplifter]

> If you calculate the pure combinatorial distance between the DNA of 2 species, you must find that you can't just brute force your way from one to the other before the heat-death of the universe.

Can you expand on this? I'm not seeing why it is implausible for one genome to mutate into another, that seems like it could be accomplished in reasonable time with a small, finite number of mutations performed sequentially or in parallel. After all the largest genome is only about 160 billion base pairs, and the average is much smaller (humans are 3 billion base pairs). So what's the difficulty in imagining one mutating into another?

[coriny]

Your maths doesn't seem right. You can estimate mutation rates very easily, and you don't end up at crazy numbers. The sequence space explored by evolution is tiny compared to the possibilities and closely interlinked. A simple example is comparing haemoglobin sequences from different animals.