We left off pondering the sort of creature capable of making a roundtrip tour of the cosmos and rejoining the source of being. Ironically, chances are, the same people who ridicule “flat earthers” are likely to be flat universers.
Could the Universe actually loop back on itself? And if you traveled far enough in a straight line, would you eventually return to your starting point, just as if you traveled in any one direction for long enough on the surface of the Earth?
While it’s easy to see how a positively-curved space can be finite and closed, it’s a little less intuitive to realize that a flat space could be finite and closed as well, but that’s also the case. To understand, simply imagine a long, straight cylinder, and then bending that cylinder into a donut-like shape until the two ends connect. This shape -- known as a torus -- is both spatially flat and also finite and closed.
Well, that's a relief. I always suspected the cosmos looked like a donut, hence the ʘ in ONE CʘSMOS.
Let’s jump to the bottom line: in an abstract sense a straight line would return to itself, but there hasn’t been enough time for it to do so:
The Universe may, on some very grand cosmic scale, truly be finite in nature. But even if it is, we’ll never be able to know. While we can travel through space as far as we like, as fast as we can, for as long as we can imagine without end..., there is a cosmic horizon that limits how far we can travel through the expanding Universe, and for objects more than ~18 billion light-years away at present, they’re already effectively gone (https://bigthink.com/starts-with-a-bang/travel-straight-line/ ).
Let's just say that if the universe were finite, it couldn’t be. Besides, Gödel.
The objects available to us in experience are much richer than those described in modern mathematical physics…. Mathematical physics deals, literally, with abstractions and there is a tendency to take these abstractions for the whole of reality. The result is what De Koninck meant by the expression “hollow universe” (Armour).
The world is explicable from man; but man is not explicable from the world. Man is a given reality; the world is a hypothesis we invent.
Of all the vicious circles one could imagine, that in which the materialist encloses himself is the most primitive, restrictive, and binding (De Koninck).
Every natural form tends toward man…. in this perspective, subhuman forms are much less states than tendencies.
the cosmos is open to another world which acts on it. And this cause can only be a living being; it is necessarily a pure spirit, a transcosmic being.