Scientific method is an approximation method. It converges on the "truth" but may never reach it. This is why Einstein famously said, "No amount of experimentation can ever prove me right, but a single experiment can prove me wrong." I quoted truth above because there is no such thing as truth really. We only have models.
And even more there is not such thing as model independent reality. When you start talking about things (e.g. light) without using a particular model of it you run into all sorts of problems rather quickly.
You are also working under the assumption that things you can't see directly can't be considered evidence. This is patently not true. We can never see electron with our own eyes directly, but we can detect it by other means.
What god do you believe exists? If you are referring to deistic god (the one that may perhaps have kicked off the universe, but does not interfere in it any more) then no one can in principle provide a proof it exists nor that it does not exist. At most we can say is such a hypothesis is no longer needed. It presupposes a lot more to assume an intelligent being capable of creating universes who either spontaneously came into being or always existed than to assume the same thing about the universe itself (i.e. dumb matter). This is why Occam's razor cuts such hypothesis as superfluous thing, because it does not explain anything new, but poses more questions.
Theism on the other hand is not simply belief in gods. Theism is belief in gods that care about human beings, that interfere in their lives, that tell you what you should do, what you should eat, on what days, who you may sleep with and in what position, gods who break the known laws of nature for their people, a god that gives itself body so it can kill it to save the humanity etc.
This theistic concept of god is quite distinct from a deistic god who may perhaps have kicked off the universe and set its laws, but who does not interfere in it any more.
And it is this theistic god that we now know is a man made invention.