To believers, God is not a 'concept', and I think that most believers can cite some experience that reinforces their belief.
Sigh. You're picking issue with the words I used instead of just answering the question.
Of course I wrote it like that. I'm not a believer and I don't pretend to be. I feel disingenuous if I write as though I were a believer without making it explicitly clear that I'm doing so. So mostly, I just write from my own point of view. I thought that the phrase "concept of God" was sufficiently non-specific to be understandable and accessable to both believers and non-believers, even though it wasn't what they might have written themselves.
I was wrong.
Let me write it in your language and see if it's easier for you:
What purpose does God serve in a world where all phenomena are explained by other systems?*
I'm also going to quote a later part of your post because I think it's relevant to this line of discussion as well.
Remember that I for one believe that God interacts with His universe all the time, and as He created the universe, science is part of that creation.
If God interacts with His universe all the time, how do you reconcile that with the statement that all phenomena can be explained by other systems?*
Science can supply facts, but science is not a person. Science cannot supply a theory to explain observed facts, people do that.
The way you've written this I suspect there's some misunderstanding as to what exactly science does.
I apologise if you already know what I'm about to write. It's not intended to be patronising, but I think we need to start off by ensuring that we're both on the same page. Low level disagreements on how science works will derail any conversation before we get anywhere useful.
Science can
not supply facts. Observations supply facts. The scientific method outlines best practises for taking observations, but they're not hard and fast rules. You take what information you can get when you can get it.
Science or the scientific method never claims to supply theories, or hypotheses, or any other act that is performed by humans. As you pointed out, somewhat redundantly, science is not a person. No one has ever claimed that it was.
The scientific method is at heart a group of best practises for obtaining and interpreting data. It's the set of ways that humans have found best allows a person to avoid false conclusions, if applied correctly. It's not infallible, but even wrong conclusions can usually be understood in retrospect as a result of limited information.
That's all it is, a tool that people use. Don't start blaming the spanner for the mechanic fixing your car wrong.
And people can be wrong. It is quite possible for two persons to interpret the same facts differently. Competing theories are common.
Firstly, people can always be wrong. Scientists are almost always wrong, because there's simply not enough information.
The only time they can be unequivocally right is when they're right by definition, like if I define the speed of light in a vacuum to be 47 twinkletoes per second. Even if I'm not exactly sure how fast light goes in a vacuum, I can still say that it's 47 twinkletoes per second, and that will always be correct even as our understanding of the actual speed of light become more accurate.
We know damn well that we can never say anything with absolute certainty. Much better than you do, I suspect.
It's entirely possible for two people to interpret the same facts differently. Again, it happens all the time. That's why peer review exists. However, at any given time there's usually only one best explanation.
Here I'm going to be technical. I apologise for picking issue with words given what I've said already earlier in this post, but I think it's an important distinction to make.
There is a difference between a
hypothesis and a
theory.
Unfortunately, in common language they're basically synonyms, and the media tends to make this mistake as well. However, generally a
hypothesis is any proposed system that explains a given set of observations. A
theory is the proposed system which best explains a given set of observations.
So while there are many hypotheses of gravity, there's only one theory of gravity that best explains all current observations of gravity. That theory may not be the best explanation tomorrow when new observations are added, but that's the nature of how the scientific method adapts to new information.
There are occasionally multiple theories on a given topic, when they all sufficiently explain observed phenomena but differ on observations that cannot or have not been made yet. That's kind of an edge case though, as for all intents and purposes they make identical predictions based on what we currently know.
Just because people can be wrong, doesn't mean there's anything wrong with the scientific method. A bad mechanic isn't bad because his tools are bad. Two people interpreting facts differently is the basis of scientific advancement. Competing theories are not common (in fact, not a thing at all), but competing hypotheses are, and again are the basis of scientific advancement.
Most believers probably can cite some subjective event that provides sufficient proof that God exists. Objectivity can disagree, but cannot prove them wrong. As far as proof/disproof is concerned, objectivity has nothing.
That's not how it works. The person making the claim is the one required to provide proof.
Please read up on Russell's Teapot, if you're not already familiar with it. It's an excellent example of a basic assumption of how people view the world, and how some people choose to only apply the assumption arbitrarily.
*I'm sorry for the long post, but most of it doesn't need reply. I'm just trying to provide information so that we can hopefully skip the "silly misunderstandings" stage of the conversation, and move on to the interesting bit. That being the bit where I learn more about the questions I asked, marked with asterisks.
Being taught how to think though... that would be dangerous I'm sure... and probably at the expense of Art class 
