Yes, but I don't think this uses the word 'exist' in the same way.
I'd say not. I tend to use two independent terms when discussing the nature of a thing's existence; I will discuss first whether or not something is real; and then whether or not that real thing exists.
To be real; a thing must be an accurate description of some pattern of behavior that things which exist conform to. (I realize this is dense/inscrutable, more in a bit.) To exist; a thing must directly interact in some fashion with other things which exist; it must be 'instantiable'.
So numbers, mathematical constructs, words; these things are real but they do not exist. We can recognize them in how the things which do exist behave. The concepts are not themselves instantiated -- ever -- but we can handle them symbolically. If I hold three pebbles in my hand, that means there is a precise arrangement of pebbles; it has a precise relationship with two the arrangement we'd call "two pebbles" and the arrangement we'd call "four pebbles" and so on. But you'll never see/hear/touch/smell/taste the number 3. It's physically impossible for that to occur; because the number, 'three', does not exist. Pebbles on the other hand do exist; you can take a pebble and throw it into a lake.
I find that this differentiation between different meanings of the term "to be" makes the discussion vastly simpler. It eliminates whole swaths of silliness (like TAG for example); I am perfectly free to say "I can prove using the Laws of Logic that the Laws of Logic do not exist."
I'm not convinced this distinction holds up all that well. For example, would you say that software "exists"? How about supply functions? Nations? Boeing 747s? People? Force fields?
Edit: yes, what gRR said.
I recognize the title could be more informative. At the same time I believe it says what is important.
I believe in a deity, I believe in mathematical entities in the same way.
The community of LessWrong (from whenceforth: LessWrong) is deeply interesting to me, appearing as a semi-organized atheist, reductionist community.
LessWrong seems very interested in promoting rationality, which I applaud. The effort does seem scattered, though, and this is the reason I post.
One has Eliezer's website with some interesting posts. The same of this community. The community links to some posts when you are coming for the first time into it, and you also have a filter for top posts. One has the blog. And recently, the center for modern rationality (in the same page as harrypoter fanfiction about rationality).
The point being there is no defined roadmap to go from AIC (average irrational chump to make an analogy to Game - which also seems to come up around quite a bit) to RA (again, rationality artist).
I write this post as to maybe generate a discussion on how the efforts could be concentrated and a new direction taken.
Should the creation of the Center for Modern Rationality envision this same concentration, this post may and should be disregard.
If it does not, then I leave it to your consideration.
Hang.