I've just read about some details of the work of the author known as Pseudo-Dionysius. I read that, as a Neoplatonist, he upheld the idea that there's a hierarchy of beings in the world (the "Great Chain of Being"), according to which there are levels of existence—the existence of a horse being more real—or fully realized, so to speak—than that of a rock, for instance. According to this author, a higher level of existence goes hand in hand with any particular thing's closeness to the source of Being, God, who is in the upper tip of the said Chain. This God's agency is depicted with the image of a volcano spewing lava; the lava flows downwards and gets solidified in the process, becoming colder and deader the lower and farther from the source it comes.

The funny thing is that in the Pseudo-Dionysius' work you also find the (Christian) idea of God creating the world from nothing (ex nihilo), a doctrine that is at odds with the Platonic notion of God-as-source. According to the former view, God creates every single being out of nothing—without any intermediaries, as would entail the lava image—, and consequently the idea of a hierarchy of beings is ruled out. Under such premises, existence would just be a binary condition: either something exists, or it doesn't.

While reading this, I recalled a somewhat wacky assumption a critic of the evolution theory allegedly put forth years ago. God has created the world ten minutes ago, all with rocks, sedimentary layers and fossils, he said. (Just to fool us? That's a possibility!) At any rate, as is the case with many—if not all—wacky assumptions, you just cannot disprove it.