"Scientists disagree on so many basic things, it impossible to take what they say seriously. Look at how upset folk are over MMR.
Science cannot explain everything. Not even close."
But that's the good thing about science. (Pausing just to note that, simplified debate aside, there is not really any one thing called "science".) It recognises that discovering about the world is an ongoing process and that theories are constantly being tested and refined. And scientists agree on a lot more than they disagree on.
Sometimes, it's not that one scientist is "wrong" and another is "right" - more often than not, understanding of a subject is incomplete and each new book and article moves the debate on, further in the direction of a complete understanding.
Science has never claimed to be able to "explain everything". You may find that some scientists, if pushed, will express the fervent hope that one day, science will give us a more-or-less complete understanding of the Universe - but they all acknowledge that this is, at present, a long way off. And that's a good thing too. The fact that there's so much more to discover. Science, unlike religion, doesn't pretend to give easy answers - it is a tool for researching the universe and asking questions. Religion is totally at odds with the questing human spirit and desire to strive to find out new ways of understanding the world and the universe - however incomplete they may be.
However, not being able to explain everything does not preclude you from dismissing some things. That's what building up a body of evidence is all about.
There's a wonderful anecdote in "The God Delusion" about one of RD's colleagues who has, for his whole life, been working on some particularly recondite area of biologial research - can't remember what, as I don't have the book in front of me. One day he invites an eminent colleague from overseas who works in the same area to come and give a university lecture - and halfway through, the professor realises that this guy's theories and evidence blow his own away - his colleague has found answers to this problem and they are totally different from the ones he himself has been working on, and moreover they make more sense. At the end of the lecture, he goes up, shakes the other guy's hand and says "My dear sir, thank you for proving me wrong."
To tumultuous applause.
Now imagine that happening in a church.
Quite.