"We are both atheists"

I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours. 

This will be a sequel to my previous post:

http://triablogue.blogspot.com/2013/10/one-fewer-god.html

In that post I offered one interpretation of his statement. I glossed it to mean monotheists reject polytheism for essentially the same reasons as atheists reject monotheism. On that interpretation, the comparison operates at this level: atheism is to monotheism as monotheism is to polytheism.

I then showed why that comparison was false. Let's try one more time. Perhaps Roberts isn't making a general comparison between monotheism and polytheism. Perhaps, instead, his comparison operates on a case-by-case basis. Maybe he's saying something like, When you understand why you (e.g. a Christian) dismiss Allah or Thor, you will I understand why I dismiss Jesus. 

Does his comparison work at that level?

i) To dismiss Zeus or Thor as individual divine claimants is misleading. That's not why monotheists dismiss Zeus or Thor. Although these are individual "gods," they belong to a polytheistic package, as members members of a pagan pantheon. In this framework, each "god" is just a special case of polytheism in general. Monotheists dismiss specific claimants because they categorically reject polytheism. They reject theogonies. It's a topdown argument. Zeus and Thor belong to a class of polytheistic deities. If you dismiss polytheism in toto, you thereby dismiss all members of that class. 

In that event, the argument from analogy collapses back into a general comparison between monotheism and polytheism.  

ii) But perhaps the comparison is not between monotheistic gods and polytheistic gods, but between rival monotheistic gods. Perhaps Roberts is saying he dismisses all monotheistic gods for the same reason that adherents of one monotheistic faith dismiss the deity of a competing monotheistic faith. Does his argument go through on that interpretation?

iii) To begin with, that restrictive interpretation is implausible. For his original claim referred to "all the other possible gods." If, in fact, his statement is actual confined to the subset of monotheistic deities, then that radically contracts the scope of the original claim. Yet the appeal of his statement lay in its simple universality. Dismissing all "gods" at one stroke.

iv) But let's play along with the restrictive interpretation. One problem is the paucity of candidates for monotheism. The big three are Islam, Christianity, and Judaism. 

Perhaps we might include the Bhāgavat school of Hinduism. That's hard to say. Hinduism has fuzzy boundaries. 

Among historical religions, very few are truly monotheistic. 

v) It depends on how we define Judaism. If we identify Judaism with OT theism, then Christians believe in Yahweh.

If, on the other hand, we identify Judaism with the Kabbalah, then that's more philosophical.  

vi) Why do Christians reject Allah? Well, one reason is because they regard Muhammad as false prophet. That's in part because the Koran contradicts the Bible. 

Do atheists dismiss Allah because the Koran contradicts the Bible? No. But in that case, Roberts' argument from analogy is invalidated by a crucial disanalogy. 

vii) We also need to distinguish between historical monotheism and philosophical monotheism. As long as philosophical monotheism presents a concept of God that's consistent with Christian theism (to take one example), then Christians don't dismiss that idea of God. 

But suppose Christians reject a philosophical version of monotheism because the details of that particular construct conflict with Christian theism. Is that why atheists reject philosophical monotheism? No. 

Atheists don't treat Christian monotheism as the standard of comparison. They don't regard Christian theism as the true frame of reference, to which philosophical monotheism must correspond to be acceptable. So, once again, Roberts' argument from analogy is invalidated by a crucial disanalogy.