Nothing against those who believe, but when you have seen and heard someone, you do not say that you believe they exist, you say that you know they exist. Is this too complicated for you to understand?
Here's the difference. Sitting over there is my co-worker Jason. I spoke with him just now. I know he exists. (And with a nod to other threads about whether reality is real, I am using the word "know" in the sense that I am sufficiently certain about it not to engage in any fruitless trips down a philosophical rabbit hole about it).
If someone else told me he didn't exist, I'd wait for the punch line, or think they were deluded.
However, if pretty much everyone else I met told me he didn't exist, at that point I'd stop saying I know he exists, and book myself an appointment with a doctor.
Edited by vimesey, : No reason given.
Could there be any greater conceit, than for someone to believe that the universe has to be simple enough for them to be able to understand it ?