Much of my beliefs are a direct response to mental illness as it was a very personal and nihilistic period of my life (nearly recovered thankfully). It acted as a catalyst for alot of my ideas that I had before in my teens but simply were not worked out. I had a strong naturalistic bias so it was unlikely I was going to be religious in response to it. it suggests I was a materialist of sorts before I ever consciously adopted it. I've often had to reject alot of the beliefs I held before as they were responsible for the anxiety/depression and that has been a major force behind the choice. But it would have been impossible for me to think the way I do today with access to some very good second hand books as its just so eccentric/rare as choice.
So my beliefs are a compromise between what can be proven, what is intellectually consistent and what is emotionally fulfilling thats been worked out over the course of nearly seven years. I have a conviction that it is 'true' but this varies from a desire to have a belief which is a true reflection of who I am, and one which can be demonstrated to be objectively true. I needed to believe something so it was never completely a choice or a conscious decision. sometimes I'd fight against it and listen to alternate points of view. its been a religious conversion, without the religion. all in all, very messy. Ultimately the question of why a person believes what they believes is nihilistic when taken to its extreme, and there is that Zen [buddhist] moment when you realise that you just 'are' and let go of the need to justify your own beliefs. not everything can be proven and we have to live with a certian amount of uncertianty.
[To clarify- as I just realised you're new here- I am a Communist, which is derived from an atheistic philosophical worldview known as 'dialectical materialism'. Unlike most atheists here, it is not based on philosophical scepticism of religious cliams but could well be described as a dogma, especially if you believe its not true
. The inner experience is emotional so (I can reasonably assume) it closely resembles that of a religion whilst not technically being one.]
Welcome to RF by the way.