This writing was inspired by the question of one ever doubting 'God' or their belief in God in a Theologyonine discussion. Its premised in a fundamental non-duality perspective.
All depends on the premise and definition of 'God' in our consideration, and what 'God' is or means to us - who and what is defining the term for us, within any given context. The 'God' of the judeo-christian tradition while presumed to be the same 'God', is still variously described. - in general, some might question such a 'god' if its character is distorted or hard to understand, or dogma about its existence becomes too illogical or unbearable. The postive light of such a god, as being Love and Light, the substance and giver of all goodness and beauty, certainly has its pleasures - this is a kind of 'god' we can grow to love, because we discover that its essence is Love itself. - therefore, in this sphere of knowledge,...life bears intrinsic value of ever potentializing worth. - it is worth living, because one finds value in being.
Fundamentally I hold God as Life, Existence, Being, Truth, Reality itself,...the source, substrate and substance of All that Is. Therefore, 'God' is Reality. Existence is inviolable. One must recognize in the stillness of Silence, in that spiritual space of BEING....this reality of existence, in its purity,... as innate, supreme, all-pervading, latent with all potential.
This truth of existence is Absolute. - what one experiences thru the limited perception of the ego is 'relative' and subject to all the changing experiences of space/time creation (in these finite dimensions). But Spirit is ever free.
Since my basal view and knowledge of 'God' as Original Reality is fundamentally THIS (this reality here, now and forever...in this moment and every moment)...any 'doubts' of its existence is utter vanity and futility. Doubt is essentially impossible, for the only Possible Truth is God, the Father/Mother of all possibility. Nothing can do anything against Truth. - however many doubts are thrown up against it, they are powerless to efface what IS. Doubts can only arise against thoughts, beliefs or concepts about God. When one surrenders all thoughts, beliefs and concepts,....there is Only God.
One cannot escape the truth of Existence or oneSelf (since 'God' and 'Self' are One). Life, Being, Light(Consciousness), Living Awareness...is its own proof, and IS All there IS. We use words to describe Truth or 'God', for they are tools/pointers for communication. They point to that which is before, behind and beyond any thoughts or words.
God is Light. I Am Light. You are Light. There is Only 'This'. In this thisness....is All ! Know this, Be this, Live this, Radiate this. - its truth will shine forth out of the essence of your being, for it is what you ARE.