That atheism is not rationally justified

[Dolorian]

I came across some argument recently. The general gist of it is that some beliefs cannot be demonstrated. Reason does not inclines us to believe or not those things. But we must necessarily make a decision because it is not possible to remain neutral on the issue. It being the case that reason is unable to settle things when it comes to the existence of God, can we then rely on hope and happiness to decide on the matter?

What this line of reasoning is implying is that given the nature of the question, atheism, while it may not be false, is not rationally justified; because reason is inadequate to decide on the matter.

The argument which is being pushed under this premise, as a follow up of sorts, is that compared to atheism, Christianity offers a superior view of life because it provides a better context for our hope and happiness (the criterion we must turn to in order to decide on the question of the existence of God).

...

The objection to this line of reasoning that first sprang to mind was with regards to turning to hope and happiness and what exactly determines this inadequacy of reason. I mean, we make certain assumptions when doing science, for example, that cannot be demonstrated but when deciding to uphold them we do not need to turn to hope and happiness, do we? Unless one would deem as "hope" the idea that nature will remain uniform.