For something to be tested as scientifically true, it must also be able to be falsified.
For instance, Newtons theory of the law of gravity is falsified when, in the absence of gravity, a brick can fly upward, therefore, Newtons theory would be true.
Of course, due to the study of black holes Newtons law has been proven wrong... but it took more than 200 years and huge technological advancements to do so.
However, If you take falsifiablity away from science, it ceases to be science altogether and enters into the realm of religion, which is basically where science is today, as they have reached their limit, for now, of what they can actually prove.
Does Science Need Falsifiability?
The issue with God, as a whole, is that He cannot be proven through falsification, which has always been, up until now, a defining factor in science.
But even as science moves from the realm of science into the realm of religion, they're "faith" as it were, exists in saying God cannot be proven (ever), but through knowledge will some day be able to be disproven, instead of leaving that door to possibility open, they have already shut it firmly.
So we can look around and see God in the flowers of the field, in the universe and laws upon which it exists, but I find it doubtful a "true believer" will ever be Christian, unless God places His Hand upon them directly.
I was once a "true believer" in Islam, and ultimately it was God's work that took me out of that belief, whether through others or through His power working on me... I think the "true believer" in the absence of a God, would need the same...
That's just my thinking on the matter though.