He might be gone.

So a note on reasoning of this form: "Who is to decide what is the metaphoric Light, if "common sense" is subject to any doubt?"

Who is to decide to question if there are any doubts about doubt itself?

This fellow's form of reasoning seems to be a form of logic or pseudo-logos that is eating itself up to the point that it eats its own tale, as represented with this parable.

The supposed benefits of doubt:

Why sacrifice a transcendental truth for immanent certainty? This is the fallacy inherent in scientism.
In settling for certainty, you cut out part of the dialectic, and hamstring the everlasting approach to transcendental truth, and to God.

I would answer that with the words of Max Planck, father of Quantum Physics: “Religion and natural science are fighting a joint battle in an incessant, never relaxing crusade against skepticism and against dogmatism, against unbelief and superstition... [therefore] ‘On to God!”

Or to add some lines to the parable: "I, uh, eh....what? Woman! Why don't you come away with me to this cliff and throw yourself off of it? Won't God have to come near to you to save you the farther away that you try to get? I've tested this by trying to kill myself many times already, yet I am not dead yet. Try it and see, for how else can you know for certain that God loves you unless you are uncertain of it?"

To which she says with a laugh, "Was I supposed to be certain or uncertain? I forget."

And so on. As for me, I seldom settle for certainty. So I'm not as certain as this fellow seems to be that it is doubt that results in an everlasting approach to transcendental truth and so on. No, it seems to me that there must be something else causing people to pursue the truth against their doubt, since that is what they are doing.