Faith doesn't enter into it. When theories collide, the winner will be the one best supported by the evidence. This happens all the time, and it is in fact, how science advances our knowledge.
When one model emerges triumphant, the former adherents of the other theory will accept it and not go off to form a new branch of science. Again, no faith involved.
Most scientists and science generally love finding out their understanding was incomplete and welcome being challenged on the facts. I don't know anybody who expresses certainty.
The scientific method is all about removing the human bias, whether in cognition or cultural matters, so that experiments done by me here in the US will yield the same result no matters who carry them out or where they're carried out. Faith is in fact the exact opposite of the scientific method, and hampers inquiry.
Saying "God did it" is not a valid answer to any question, and worse than the scientist's admission of ignorance, it really means "I don't know and I won't bother to find out about it either, because the answer might upset me".
Science has always been more humble than religion in my opinion. Nothing is certain.
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