No scientist worth his salt will say “There is no God, and I’ll prove it.”
It is impossible to prove that something does not exist, because those who believe it does will always just say “you just haven’t found the proof yet.” Ample evidence of that in this thread (“who knows what science will find in 25 years”). All you can do is show that there is no currently known evidence that something exists, and that the rules as currently understood don’t indicate that such a thing would exist.
Conversely, it can be very difficult to prove that something does exist. Frequently all you can do is provide repeated evidence, through observation and experiment, that something does, indeed appear to exist. This can be further strengthened by development of theories, hypothoses, and guess-work, that seem to not only predict the existence of said thing, but also to predicts the properties and behaviors of such a thing
This is what the scientific method will tell us. Now, scientists are human and humans are prone to hyperbole and many will tend to overstate things as certain.
An person may say “after 10,000 years of humans searching for positive proof of unicorns, none has been found. This means there is no god.” That is not entirely accurate. It is an overstatement of a lack of evidence. However, I think we can all agree that there probably aren’t unicorns running around some spare corner of Asia.
Conversely, abundant evidence may be overstated as well. I may say, “I’ve seen my front door thousands of times. Every interaction I’ve had with my front door meets my expectations as to what a door is and how it will behave. That thing attached to the threshhold at the front of my house IS a door.” There is a possibility, however, that the door is really a hologram and a thin, 3’x7’ alien is masked by it and replicates the functions of your neighbors actual door.
Science does not prove or disprove anything with certainty.
If you will accept that there appears to be concrete evidence for the existence of a god or spiritual energy, but that you, in your heart, feel such things must exist and you’ll leave it to future scientists to prove it, if they can then I have know problem with that.
If you feel that there IS concrete evidence for the existence of a god or spiritual energy then I am going to expect evidence of the claim.
I do not feel that me requesting that evidence is making a positive thesis that such a thing does not exist; I make no such claim. I claim only that such a thing would be contrary to all existing evidence and theory and as evidence of this “claim” I direct you to all the existing evidence and theory.
And yes, saying something like “God answered my prayers and allowed me to get pregant” is a positive claim of concrete evidence of the existence of god. You can not prove it one way or the other with that one woman but you can run tests to see if praying for pregnancy leads to a higher rate of pregnancy. Again, no absolutes, but a claim was made, and a claim was tested.