Regarding any ultimate reality, it is not something for which I am, or believe I will ever be, completely certain. Philosophically, I'd call myself an agnostic on that matter, here defined loosely as one who is without knowledge rather than to the specific class of people who say that knowledge of an ultimate reality would be impossible to attain beyond a reasonable doubt. Pragmatically, however, I would have to say that I am an atheist, fully disbelieving the existence of any of the currently offered non-scientific explanations of the universe. May the gods convince me otherwise before damning my soul to an eternity (or age...a really long age) of torment. Currently, I am unconvinced.
Percy Shelley, in his essay "The Necessity of Atheism", wrote the following:
"If he is infinitely good, what reason should we have to fear him? If he is infinitely wise, why should we have doubts concerning our future? If he knows all, why warn him of our needs and fatigue him with our prayers? If he is everywhere, why erect temples to him? If he is just, why fear that he will punish the creatures that he has, filled with weaknesses? If grace does everything for them, what reason would he have for recompensing them? If he is all-powerful, how offend him, how resist him? If he is reasonable, how can he be angry at the blind, to whom he has given the liberty of being unreasonable? If he is immovable, by what right do we pretend to make him change his decrees? If he is inconceivable, why occupy ourselves with him? IF HE HAS SPOKEN, WHY IS THE UNIVERSE NOT CONVINCED? If the knowledge of a God is the most necessary, why is it not the most evident and the clearest."
I'd like to think that we would be convinced of some transcendent truth or being on a universal level. What I find is a large collection of beliefs, all of which are completely unfounded on any certainty beyond the present reality. Each religion is convinced that they are the exclusive proprietors of a revealed truth, yet they defer proof of their claims until the afterlife. Some meditate to find proof of past lives, others worship a god and feel connected to his (sic) divine presence. Men prophecy as moved 'by the Spirit' and cut themselves in honor of the local gods, all while maintaining that they are certain that they are pleasing their select deity. It is completely reasonable to accept that a god or other entity is responsible for all of the variation that we see. Perhaps the Hindus are right in encouraging the worship of <INSERT YOUR PET DEITY HERE>; maybe all religions lead to the same place. Across the globe, humans are worshipping some object or concept in hopes of a better life, possibly indicating that knowledge of a god is "the most evident and the clearest". In many respects, we are better as a race because of people's dedication to their gods. Fear of repeated sufferings on the endless wheel of birth-suffering-death or of endless damnation, often paired with the belief that a religion's traditions are culturally beneficial, has resulted in general social moderation. It is difficult to say what would have happened to us if we would have remained a godless species; nature indicates that we would have managed well enough.
It is also possible that a god wants to have people pursue it and has made this knowledge less universal than Shelley demanded. Perhaps we are wrong, those of us who want to have conclusive evidence before accepting (or continuing to accept, as is the case with me) the claims that religions make. Many former believers have, as I have, "tasted and seen" but have not terminally concluded that "the LORD is good." Trances and rapturous worship services are strong evidence that something is happening to the practitioner during their rituals. Some prophesies have been proven true, some even coming out of our own lips. We have experienced wonderful highs, endured long spiritual droughts, and found the still, small voice of comfort in our times of trouble. As I'm sure you're aware, though, these experiences no more prove a universal truth or an ultimate reality than the agonized screams of raped children prove the non-existence thereof.
Having said that, I conclude by stating that it is highly probable that religions were the product of men and women afraid of their surroundings as they began to wonder about their origins and noticed how infinitely small they were. In the years since, science has filled the gaps in their understanding and overturned many religious rulings on the nature of the universe. We are coming much closer to understanding the truth about that often-asked question, "Where did we come from?" Unfortunately, science will never be proven to be the only truth, nor do I believe that we can conclusively know the exact nature of our origins through science. Religions will persist throughout our existence in this universe as a result of one glaringly obvious problem: our knowledge of the universe is finite. Allow me to make an assertion in spite of this limitation - a just, intervening god who created man and woman in the garden to allow them to be tempted by a talking serpent, only to kick them out when they made an honest mistake and were obviously repentant, who felt the need to make humans grovel at his feet for several millennia before providing a solution, only to make it "the foolishness of the Cross" so that he could ask "where is the wise?" and "set a stumblingblock in Zion", and who requires "all men everywhere to be saved" is a complete fable. I will no longer cower in fear of being the "fool [who] hath said in his heart, "There is no god"". Let the true god arise and all the rest of it be silenced. Oddly, I don't hear any takers on that request.