Compmage is pointing out a contradiction in your position. You're demanding an ultimate cause for the scientific perspective, but not of the religious perspective.
For example, if you insist of science that the Big Bang have an origin, then you must equally insist of religion that the Big Being have an origin. And if your answer for the Big Being is that he has existed forever, then why do you reject the same answer for the universe?
JEP: Let’s see if I can add to this thread. Something started this thing we call the big bang. Things in motion have to be put into motion by something; and we can tell simply by observing our universe around us, that it is expanding rapidly. So, what caused this?
Something did and it could not have come from our universe because our universe did not exist before the big bang.
Our three spatial dimensions of height, width and depth and our fourth dimension called time were created in the big bang. Before the bang, there were no spatial dimensions in our universe in which to put anything that it could exist. There also was no time in which anything could exist. The basel element of the very word called existence requires a space-time constituent in order to be sensical.
So, we can determine that something ‘caused’ this universe.
If God exists then doesn’t He also require a cause? No. And for the very same reasons that the big bang DOES require a cause. If God created the universe and before this creation there was no time, then we can quickly determine that there was no such thing as the words before and after because they are dependent on time. If there is no such thing as a ‘before God,’ then it becomes a moot question to ask what created him because nothing could have pre-existed Him in order to ‘cause’ Him. God just always was. Interestingly enough, this is what the Bible teaches and I find it fascinating that it also teaches that the dimension called eternity that God lives in is a time-less phenomenon.
Please read the writings of philosopher Auther Custance for more on this.