Hi Neil--
Thank you very much for your comments. You ask a superb question. I actually had a section in my essay that addressed your question, but I deleted it for reasons of space constraints. So, I welcome to the opportunity to revisit it here in the comments section.
As I mentioned in my previous post, in response to Jeff Schmitz, one may envision three types of infinity: mathematical, physical, and metaphysical. In my opinion, "metaphysical infinity" concerns speculative statements about Nature which invoke various sorts of infinite characteristics. For example, our current cosmological theories seem to be telling us that spatial sections may be physically infinite. OK, fine, that's a fair point of view. However, I consider it to be a scientifically-informed metaphysical statement about Reality. It is a metaphysical statement because I don't see anyway to make scientific statements on objects, etc., that are, in principle, always unobservable, either directly or indirectly.
I do not reject statements concerning metaphysical infinity. I just don't consider them to be scientific statements. The purpose of my essay was to gently suggest that physics does not need physical infinity. I conjecture that everything that we need to do, physically, can be accomplished by relying on an appropriate-sized Bravo. I make no criticism of either mathematical infinity or metaphysical infinity. Both can be extremely useful within their fields.
Finally, I really don't have an ontological dog in this fight. As a physicist, I started out believing in physical infinity. I came to question the concept of physical infinity only after reading papers by "Team Ellis", considering carefully what Dedekind was telling us, and by taking a hard look at the subject of "super tasking" (the notion that an infinite number of acts, etc., can be accomplished in finite time and so on). I concluded that physical infinity was neither necessary nor useful for doing physics. However, someday, some team of physicists may show how a phenomenon can only be explained by physical infinity. In such a case, I would admit defeat and move on. It wouldn't the first time that Nature threw physics a curveball.
Best regards,
Bill.