Deogolwulf is the sort of fellow who uses 'proposition' while obviously meaning 'statement'. Also, some of the first paragraph is pure unreflective sophistry. Still, the second half:

Could you think of any way to test or affirm this strange belief of yours even empirically-scientifically, let alone quarkly? Of course not, nor could there be any such way.

Following this epistemic attack, I am imagining Deogolwulf holding up a mirror to TGGP's face and stating "No, TGGP, you are the metaphysics."