However, I came across an interesting new (to me) perspective on this. The American magician Penn Jillette argues that there are two questions here:1. Is there a God?2. Do you believe in God?The first question is the one I would answer with agnosticism. I don’t know. However, if I consider the second question, Jillette argues there are only two answers. Belief is ‘active’ – you either do or do not believe. He then argues that if you say you ‘don’t know if there is a God’ then you cannot actively believe in God, thus you do not believe in God. Making you an atheist.
Clever, but I do think there's a bit more nuance in the way most people use the word "believe". It can often mean "I think so, to the best of my knowledge," but there's also a sense of wishful thinking involved too, an "I hope so." Sometimes when you say that you believe in someone, you mean that you not only think they'll act in accordance with your expectations, but that you're placing some trust in them to do so. Saying it to a loved one can be meant precisely to that effect, your profession of belief acting as a hopeful gesture to inspire them, a way to prod them to be worthy of your faith in them.
And in a more typical religious sense, people can think of belief like an arrow aimed at a target -- it's another word for the effort they make to attain whatever they think a perfect state of bliss or grace or understanding would be, expecting they'll fall short in the meantime. In both cases, you might even profess belief precisely to mollify any doubts you have.
But either way, an atheist version of tricky wordplay equivalent to Anselm's ontological argument isn't likely to have much effect on the murky soup of desire and fear that constitute most people's religious beliefs.