The irrationality of theism has become somewhat of a slogan many modern strands of atheism. Some of those who have said it have admitted that it might possibly be going a bit far, and this essay is going to try to show that they actually do. There are arguments against the slogan "theism is irrational" that involve the pragmatics of debating people, that it will insult them and will take away from the debate at hand. While this is an important point, there is the simple re-buttal "My job isn't to sound convincing but to simply state the truth."
The purpose of this essay is to argue that the claim that "theism is irrational" isn't even true.

A recap on what has come before
This essay is the sixth in the series.
The bulk of the argument came in the articles that came before it.
This essay is almost a summary and conclusion of the points that preceded it.
The first two essays were about logic and reason, to remind ourselves of what they are and why they are useful to us. After all, if we are calling something irrational then what do we mean? The common answer is that a belief is irrational if in forming it the believer neglects reason.
My response to this was to show that it's not always appropiate to apply reason to a situation. It seems more appropiate to call a belief irrational if in forming it the believer neglects reason that they ought to have applied.
With that in mind, I can outline 3 ways in that theism can potentially not be irrational:

When the theist makes literalistic claims
Theism is a claim about metaphysics and metaphysics is definately a rational endeavour. However, it's not a 'prove it from first principles' form of reason.
Metaphysics is a subject of competing paradigms.
With paradigms, reason cannot directly prove one and falsify another.
Instead, we can merely show incoherencies and inconsistencies and gradually tweak our worldviews to make them that little bit more coherent.
That means that even if theism is false, it is quite possible that it is a position that a rational truth seeker will find themselves as they gradually make these adjustments. It is quite possible that theism is the best position, considering their understanding of the world at that moment in time.

This doesn't mean that paradigms can be used as an excuse to dodge reason.
If an opponent is holding to the same worldview with the same tired arguments with no improvements in the last 5 years, apparently ignoring all the objections that have been levelled at them, that seems to be symptom that they're not listening to reason and therefore are being irrational.
My argument is simply that we cannot judge purely by our disagreement.
If we want to judge the rationality of our opponent then we must judge by the interactions of our opponent. Do they genuinely take points on board and consider them, or do they just continue to preach their stale apologetics at us?

When the theist avoids literalistic claims
This is when the theist refuses to state solid claims but rather uses ill-defined metaphor to try and get their point across. Metaphoric reason isn't like mathematical logic where there's a clear cut method to work out whether an argument is valid. Instead, such arguments appeal to our intuitive grasp of the concepts at hand. So although their arguments aren't detailed and technical, this doesn't mean that they aren't applying reason to the matter at hand. Sometimes in life we have ideas that just can't be expressed in sharp logical concepts and metaphorical reason in the only way to address them.
Religious ideas are often of this sort.

Ofcourse, this is only justified if they too recognise that their ideas aren't solid, so they the most they should be doing with these arguments is 'thowing it out there', and trying to explain themselves. This correlates with the attitudes of moderates who often prefer to 'share' rather than 'debate', that is throw out their insights and let them naturally influence their 'opponent's' thought. This does mean that we're unlikely to get clear cut answers, but many forms of discourse aren't about finding clear cut answers.

When the theist ignores rational arguments altogether
This is when the theist is working on faith.
This is justified when a the theist is 'exploring'.
It might be that they are putting their trust in a church or organisation and see what they learn. It might be they've been inspired with some ideas that they want to let grow to their natural conclusion. The rejection of reason is justified as you cannot apply reason until you have ideas that are better formed and their religious ideas haven't reached that level instead.
So it's like trying any new activity - just try it and get stuck in without thinking about it and it's only when you've gotten a basic mastery of it are you capable of any reasoning in it.

That doesn't mean it's blind faith though.
Not every idea of theirs will be clearly articulate, but there is potential for them to disagree with the organisation on issues that they are familiar with enough to articulate. What's more, the practice of the people involved will be a measure by which to judge them. So although there are some issues that they will refuse to reason about, some articles that reason just can't touch, there will be some kind of reason that will be applicable, e.g. "Seeing the antics of this organisation, it is really a good idea to trust and get mixed up in them?"
What's more, their faith justifies their exploration and 'going along with it' rather than the 'truth' involved. So arguments from faith would be limited to "let me try this out without demanding all the answers" and couldn't really be used to convince another person.

A rational theism will likely be a combination of elements of these three.
Enough coherence in their literalistic beliefs to not be absolutely absurd beyond all belief combined with some vague ideas related to their outlook on the world and an attitude of faith to the whole practice, of stepping into the unknown on a limb. All this would be justified on whether it was making the life a better one, and if this approach started to get them down then they would likely lose faith. Some have claimed that faith and religion are necessary to our psychology, our natural way of dealing with our human nature. While I think that calling it necessary would be going too far, I certainly think that's a valid approach to life, and in that way can be rationally justified.

Does this mean that theism isn't irrational?
Well, put it this way:
Later on you might go to town or switch the TV on and see fundy preaching for Jesus, flinging biggoted slogans about deviants and non-believers, using threats and scare tactics, and responding to criticism by shouting it down and repeating the slogans over and over as it that would make them more believable. Basically, some character that lives up to every dirty stereotype that is associated with the irrationality of theism. My argument isn't designed to defend these people at all. My point is that it's not the theism that's the problem - the theistic position can be held in a rationally legitimate way.
What determines the rationality of the belief is the attitude that the believer holds towards it.
Are they willing to question it?
Do they even take criticism on board or do they just block it out?

Contrast between Jack and Jim:
Jack and Jim believe in God. Both use a form of reasoning.
Jack has currently been convinced by the cosmological and teological arguments but is open minded and will return to atheism if he was to find these arguments flawed.
Jim has always believed in God and will give reasons for it citing science, philosophies, common sense etc. However, any attempts to discredit his belief are seen as work of the devil and must be dismissed as sophistry.

Jack is clearly has a rational belief in God.
Reason guides his belief and he will follow where the arguments lead rather than cling to a false belief. That's not to say that an argument will bring an instant conversion, it might take time for Jack to be convinced of the argument's validity, but criticisms will be taken on board rather than dismissed so there will always be potential to learn better and change.
Jim on the other hand isn't interested in the results of reason at all.
He's more interested in apologetics. He'll use reason to criticise other people and make his position look more credible, but won't go as far to use it to honestly access his own beliefs.

We can still make arguments about the irrationality of theism, but it's an argument with socialogical premises rather than theoretical, and it attacks particular theologies rather than theism in general. It's clear that fundamentalist evangelicals of America are likely to be extremely irrational in their beliefs while modern Christians in Europe can have a very rational attitude to their religion. To expose the irrationalities of theism isn't to expose the theoretical flaws in the belief, but to expose the practices and attitudes of various theistic groups. The actions of the RRS have certainly seemed to implicitly recognise this, the blasphemy challenge encouraging atheists out there to declare what they really believe, and "not be afraid anymore" of those who tried to scare them into religious conformity.
The battle isn't so much against theism in general so much as the particular theologies that try to exorcise control over it's believers.

To conclude...
So I've brought forward an argument that theism isn't necessarily irrational.
It's designed to combat the sweeping generalisations that many of us atheists make.
It's also designed to make a clear distinction between moderatism and fundamentalism, how moderates tend to treat faith and religion in an appropiate way while fundamentalists abuse both faith and reason. The main point that I hope to drive through as follows:
We cannot judge rationality by the content of the belief, only by the attitude of the believer.

So if a new player comes to our board, it's not by their atheism of theism that we judge their rationality, it's how they respond to argument, criticism and debate that is the telling characteristic. It's not whether they agree with us but their honesty and humility in a disagreement.
You only have to take a quick browse through internet forums to see that there are many strong prejudices against theism among atheistic communities. My hope that the arguments presented in this collection of essays will help ease such prejudices.