"it makes it seem like the entire human race was one big accident"
That's basically the jist of it.
...Life evolved from single cells anyway. And while near impossible to reconstruct, it's been proven that in an undeveloped world filled with molten gasses that a mix of certain chemicals at a certain moment can produce a single celled organism. That organism splits, etc. etc. etc., evolution, etc. etc. etc., animals, etc. etc. etc., more evolution, etc. etc. etc., humans.
In a world of empty space and literally NO source of heat, the world would be VEERRYY cold. Colder than can really ever be possible again, even in space. An atom can easily rip under the pressure, and, ker-explosion, blah.