I realize that I can’t know for sure whether Bertrand Russell’s proverbial teapot is in orbit around the planet (or is it around the sun?), but I have no problem* categorically stating that I believe it is not.
Except that’s not quite true. I have a bit of a problem with the word “believe,” since it misleadingly suggest I’m talking about a belief or faith. In fact, my view of Russell’s Teapot (and God) is more of an opinion. It’s a best guess.
The problem is that while we make a distinction (at least I do) between “belief” and “opinion,” in colloquial speaking (and writing), we generally use the verb “believe” to refer to both kinds of views. I have a pretty extensive vocabulary, and I’m not afraid to use it, but I don’t think I’ve ever used the word “opine” in my life.
The other option, of course, is the verb “think,” and I try to use that when I’m referring to my view on deities — that is, I think there aren’t any. If I were a little less mindful of my Rule #1, I might respond to queries about what I believe by saying, “I don’t believe, I think.”
(pic via xkcd)
Atheist Etiquette 
Posted by ObSciGuy (Paul) on October 26, 2010 at 9:38 pm
I tend to think of belief as something like “cognitive content held as true ” while an opinion implies more of an evaluation or judgment of some kind, or belief that’s only weakly held as true.
As for the word belief being misleading, I think the word is fine to use. Although I usually end up emphasizing that how one comes to hold certain beliefs — and whether or not they’re willing to acknowledge those beliefs might be wrong — tend to be the more interesting thing to talk about 😉
Posted by Stepan on October 27, 2010 at 1:49 pm
You also need to pay attention to the distinction between “believe in” (as in “I believe in Santa”) and “believe that” (as in “I believe that I can do something”). IMO, “I believe that” is simply a stronger version of “I think that” but doesn’t carry the supernatural connotations of “believe in”.
To me saying “I believe in evolution” doesn’t feel right. But I don’t have a problem saying “I believe that the theory of evolution best described how we ended up with the current diversity of species”.
Heck, even saying “I believe in Jesus” is ambiguous. I happen to think that Jesus was a historical figure while I don’t subscribe the any of the Christian beliefs about his divinity. So do I “believe in” him or not?
Epistemology is fun!