Our human brains are hardwired only to respond to stimuli in a very narrow range. For example we can't see radio waves, or gamma rays or hear ultrasonic sounds. We know such phenomena exist only because science and technology evolved to the point where they could be detected.
Given the non-physical and supernatural nature of any God(s) that may actually exist, and the current limitations of science, technology human intellect and consciousness, I wouldn't pin my hopes on any "proof" of Divinity through such means. Maybe the Universe we live in is explicitly designed not to allow us such proof. If the existence of Heaven and Hell were proven, everyone would do everything they possibly could, to become saint-like - to avoid the fires of Hell and reap the rewards of Heaven. If we knew that Jesus\Allah\Vishnu were watching our lives, and making decisions about our afterlives based on what they say, what saintly lives we would live!
But would behavior based on such knowledge be REAL spiritual growth? No, it wouldn't. The child who refrains from stealing candy because they fear the consequences of getting caught, is not the same as the child who refrains because it goes against their moral nature. Perhaps the moral\spiritual nature that mankind aspires to (or should aspire to) is not one that can be attained if it's based on fear of consequences or desire for rewards...fear and desire in things that can be PROVEN.
Now there are people throughout the ages who claim to have experienced subjective proof of God's existence - whatever that means to them. They have experienced it through religious\spiritual practices and usually when they have attained a certain amount of self-denial, self-discipline and selfless service. They usually have sacrificed - and maybe even suffered- a great deal before such "proof" has been experienced.
Maybe that's the way it works: maybe when we reach a state of spiritual growth that is based on who we are - as opposed to what we want (or don't want) to happen to who we are- we begin to see even a glimmer of real proof for our spiritual beliefs. By REAL proof, I mean phenomena that can't be explained by emotional projection, physical\psychological illness or abnormalities, self-induced states of consciousness (where we experience what we ourselves have created), wishful thinking, and all the other things that masquerade as manifestations of Divinity.
My suggestion to anyone who wants proof of God's existence is to follow whatever spiritual\religious paths that resonate with you and see where they take you. There are many religions to choose from, and there are many spiritual practices (e.g. forms of meditation). One thing I would definitely keep in mind is this: do NOT abandon reason on your quest (more thoughts about this at
Reasoning About Religion) This advice sound like a no-brainer but god-by-delusion or god-by-fallacy are easy traps to fall into. For example, if we believe that God exists because of all the wonderful things that happen in our lives, then every wonderful thing that happens in our lives will be "proof" of God's existence. We'll forget that atheists too have remissions of cancer , win the lottery, find love when they most need it, and all the others thing that seem to pass for proof in this age of instant gratification and shallow thinking.
As another example, when the pastor is preaching, and tells the congregation "I can feel the presence of the Holy Spirit moving in the house today" and everyone in the congregation swears they felt it too, that doesn't necessarily mean the Holy Spirit was actually there! What might have been there instead is the Pastor's skill at appealing to -and manipulating - the emotions of the congregation, the strength of HIS belief that the Holy Spirit is right there visiting HIS church, and the powerful desire for such a visit to be real to the congregation. When we strongly want something to be true in a relationship - whether it's with a co-worker, friend or spouse - don't we will usually find "proof" of it's existence by interpreting reality in ways that substantiate our beliefs? Isn't that one of the reason that people go to therapists - so they can see reality more as it is, than how they perceive it to be.
If we can alter our perceptions of reality to "prove" assumptions about people who we can see, hear, touch and interact with in the physical world, how much more do we bend reality in the directions we want it to go when it comes to something that we have no sensory proof of - like God?
There is a passage in the Bible which says 'be still and know that I am God". For those who want to know God, perhaps that stillness is the result of decades of prayer and\or meditation.. Perhaps it's a solitary walk in nature... Perhaps it's listening to a piece of music or a painting. Perhaps we go our entire lives and never find any such stillness, any such God, or any such proof of even the possibility of God. But isn't it worth at least undertaking the journey of faith - with reason as our companion? Maybe what is most important right now isn't whether or not God exists, but whether or not we dare to prove - or disprove it - for ourselves. Another thing to keep in mind is that one of the greatest obstacles to finding truth is thinking we already have...