Let's say that science proves that God exists

[Cyberman]

The only place we know where evolution took place (assuming it works as its supposed to) is on planet earth, with abundant water, stable seasons and just the right distance from the sun. Not to mention a core that gives off a magnetic field that shields us from the harmful effects of the sun. From what can be ascertained, not only do very specific planetary conditions need to be satisfied but also universal conditions such as the right strength of gravity to form planets, form stars, galaxies and so forth. If life were tunable to the conditions as you suggest, we should see life that adapted to conditions on the moon or mars but so far no evidence of that.

Just for clarification: Earth is most likely not the only world in the Solar System we know of that satisfies the conditions for liquid water. As far as can be determined, Jupiter's moon Europa has a liquid ocean beneath its icy crust, which has nothing to do with being "just the right distance from the Sun" but is the result of tidal interaction with Jupiter itself (the same tidal forces that make Io the most volcanically active body in the Solar Syatem). Not to mention that Mars is now known to have had liquid water flowing on its surface within at least the last few years.

As for "the right strength of gravity to form planets" etc: are you aware that gravity is a function of the mass of an object, meaning that there is no such thing as a single "right" strength?

Finally, we may not - yet - have found evidence for life having adapted to conditions on Mars or the Moon, but we do know that life can exist, even thrive, far outside the narrow range of conditions suitable for human life. Organisms have been found on and around oceanic thermal vents, for example, as well as in the most arid of Arctic environments, the cores of nuclear reactors etc. Based on such a proliferation of life adapted to extreme conditions, the odds of finding examples of life in far less hostile environments (such as the Europa ocean) would seem much more likely than there being none to find.