This was from much earlier in the thread, but perhaps it's time to review this and see which, if any, of these points you're prepared to reject yet.
Here is my list of why I believe we may be unique in this galaxy at least.
1. Right distance from our sun.
2. Right planetary mass.
3. Plate tectonics.
4. Right mass of our star.
5. Jupiter-like neighbor.
6. Oceans, [ not to much. Not to little.]
6. Stable planetary orbits. [ Giant planets do not create orbital chaos.]
7. A Mars. [Small neighbor as possible life source to seed an Earth like planet, if needed.]
8. And last but by no means least. A large Moon. [At a very right distance to stabilize the Earths tilt.]
9. Seasons not too severe.
10. Our atmosphere.
11. Right position in galaxy. [ not in center, edge or halo.]
12. The exact amount of carbon. [ Enough for life. Not enough for runaway greenhouse as Venus has]
13. Evolution of oxygen. [Invention of photosynthesis. Not too much or too little. Evolves at the right time.]
14. Wild cards. [Snowball Earth. Cambrian explosion. Inertial interchange event.]
Among many other reasons. We still don't know exactly where life began. Was the Earth seeded by asteroids or meteorites? Did it start here in a million coincidences with inorganic elements somehow becoming organic and then evolution taking over to produce what now exists on Earth?
When I was a kid, I always believed that if life [ especially intelligent life] was abundant in the universe, then there was a god. If not, we are an accident or a freak of the laws of physics.
1 and 2 are generally OK, though we don't know for sure that Earth-like planets are the only places complex life might arise. (As I mentioned, there are large satellites of gas giants; the twilight zones of planets around red dwarfs, or stuff we haven't thought of.)
3. How are plate tectonics a requirement? Also, do you have any idea of how common tectonic activity is on other planets? (From what we've seen in our own solar system, it seems to be relatively commonplace.)
4. As noted, that's a great big maybe, but I'm fine with focusing our search on stars like Sol. There are billions of these in our galaxy alone.
5. I've addressed this bit of speculation already. It could well be that lack of a Jupiter-like neighbor could result in MORE chances of evolving intelligence. Besides that, do you have any notion that gas giants are scarce? (In fact, the evidence points to the opposite conclusion.)
6. The presence of liquid water is pretty much included in assumptions 1 and 2.
Other 6. What? Gas giants don't have stable orbits? What does that even mean?
7. There's no evidence that terrestrial life started on Mars. It's an unparsimonious theory on abiogenesis.
8 (last but not least except for the others). Another bit of nonsense. You assert that a stable orbit isn't possible without a large moon. Why?
9. Why? A planet with no seasons (no axial tilt) might be more amenable to life, but a planet with a more severe axial tilt isn't necessarily anathema to life.
10. The atmosphere on the Earth has changed over time. Our present atmosphere is largely the result of life, not a prerequisite to life.
11. There's no evidence that life couldn't not exist nearer the galactic center (life can evolve in the presence of UV radiation) or nearer the galactic edge. Even so, there's an awful lot of territory in between.
12. Carbon is abundant in the galaxy. We know this for sure.
13. The element oxygen was forged in stars. I take it, you're talking about the presence of O
2 gas in the atmosphere. I already addressed this in number 10. At any rate, O
2 in the atmosphere was not an "invention". It was the result of the evolution of photosynthesis. With this gas in our atmosphere, some organisms evolved that make use of it (and more or less convert O
2 to CO
2 in the atmosphere). Again, life evolves to fit the conditions rather than vice-versa. On a planet without abundant atmospheric O
2, you wouldn't see organisms adapted to abundant O
2.
14. What do you mean by these things? The Cambrian Explosion is pretty well understood.
And what are the "many other reasons"? If these are the cream of the crop, I doubt these many others will be more persuasive.
The last bit sounds a lot like creationism or a supernatural explanation of some kind. You're basically saying, that you once thought the presence of life implies the existence of a god. Then you say, "If not, we are an accident or a freak of the laws of physics." I have no idea what you mean by this. Is there any event that is not an "accident" (if it's not the result of a deity)? In other words, if the option is "accident" or "by intention", then everything is "accidental", isn't it?
And what do you mean by "freak of the laws of phsyics"? You mean that if life were abundant, it would imply that natural law has somehow been violated? Why?