In agreement with the Big Bang theory, where the existence of the Universe was once an immeasurable "ball" of infinite density and mass, and wherein a reaction took place causing the creation of the Universe; was the matter always existent? Was the matter created? If everything has a beginning, would not the matter need a beginning as well? If science cannot explain such a question, then why is the unexplainable or supernatural not more plausible than "no, it wasn't created", considering that science will never be able to explain before the existence of time and space? (And yes, I'm aware of quantum gravity and physics)
After I replied, he said only: "I thank you very much for you reply, and the information relating my cosmological questions. This was very informative. Again, thank you!" This leads me to be hopeful that my response actually may have been helpful to a person who did not know why supernatural explanations are less valid than natural ones. If it can shed any light, then I would like to share it:
The second part of your question is why supernatural hypotheses would be considered less valid than natural hypotheses in claims of causation. The short answer is “things that do not exist cannot be the cause of other things.” This is not a claim that supernature does not exist. It is a statement asserting that in order for anything (including supernature) to be put forward as a valid cause, that “thing” must at the very least be existent. Nature (matter) is known to exist. Supernature is not known to exist. So, if we wish to posit supernatural explanations, we then compound the problem by putting forward an explanation that also needs an explanation. In other words, to make our supernatural explanation even begin to be valid, we need to find a way to show that there actually is such a thing as supernature that can do what we're claiming. Until we can examine supernature, we can't make any valid assertions about what supernature is or what it does.
So, we have an unexplained event-X. And we have nature which can be examined to see if it can do what is required to achieve X. Then we have supernature, which we can’t examine, neither can we demonstrate, and about which we can make zero informed claims. So it is literally just an unknown variable: Y. In this case, if we put supernature forward as the cause, we’re saying something we can’t explain was caused by a thing we can’t know anything about and for all we know doesn't even exist. So, mysterious event-X is caused by unknown, possibly nonexistent cause-Y.
Saying Y caused X where Y cannot be defined is not an explanation.
I hope this helps.Part of why I put this forward is that it seems to me to be the first step in many conversations that gets shoved out of the way as though it doesn't matter. We forget to verify our cause exists and jump into arguments regarding what it does, what attributes it may have, what motivations (if any), and so on. However, we can't verify any of our claims about this cause-Y are valid if we can't examine cause-Y. It's a very different question to ask "can this occur naturally," where we have nature to examine and investigate the answer, than to invoke supernature, where we have no means to compare claims against the cause-Y we're claiming.
The practical benefit, I hope, will be less people arguing with theists about what sorts of things god does/doesn't do, and whether or not there is actually a god. I would hope that the atheist who finds himself arguing against endless or repeated claims of god's attributes or actions would see a light come on and ask "Wait--how can we be arguing over the attributes or actions of something we can't even say exists?"