“Unwelcome Guests,” by James Wood. The New Yorker, 8/22/2016.
There really was an English philosopher named John Wisdom who died fairly recently in 1993. With a name like that, his occupation was set from birth. He even looked like a philosopher. (Of course, the lighting of this photo was arranged to highlight his wispy, philosopher-like hair.)
He devised this parable that has been repeated many times with minor variations:
Two travelers pass a garden neat and tidy and full of life. One of the travelers suggests this is proof a gardener must be tending it, although no one can be seen.
The other traveler disagrees, so they put all sorts of surveillance equipment in the area to detect anyone’s presence, but no evidence is found.
The skeptical traveler asks the believer if there is any difference between a gardener who cannot be detected and a gardener who does not exist. Does existence require some means of detection? If detection is somehow impossible, is it any different from an abstraction?
This is an obvious metaphor for the existence of God, who is undetectable. For the skeptic, an invisible God is not believable. For the believer, the tended garden is evidence enough. Both have valid positions. Non-detectability is not proof of non-existence.
Not only are both views valid, but since neither can invalidate the other, there is no meaningful difference between them, anyway.