By other words, properties of strings, false vacuum, etc are mathematical/logical properties.
But strings, vacuum, etc are themselves being mathematical result of more fundamental object(s) - multidimensional space or something else - then the universe seems to be never-ending chain of mathematical processes without "the most fundamental object" at all. In this case all objects in the chain are logical-mathematical, but we will never know initial conditions, thus we have to take some intermediate-level conditions (intermediate object like strings, or vacuum, etc) and then calculate mathematically what is universe "from this level up" - and this corresponds to all actual phenomena we see in actual universe. Including emergence ("coming into existence) of all "upper level" objects (like photon, proton, electron, magnetic field, etc) as logical-mathematical consequense of "lover level" objects (strings, vacuum, etc).
Say, where does "existence" of magnetic field come from? Does magnetic field exist in nature "by itself"? And its existence does NOT follow from anything else? The answer is - not. Its "existence" is just mathematical result of MOTION of electric charge. MOVING electric field is what we label "magnetic field".
Same with a photon. Does it "exist" by itself in nature, or it is mathematical result of something else? Answer - it is just electric field of accelerating charge. Equation of electric field for accelerating and non-accelerating charge has different solutions. First is an electric field which we label "a photon".
So, where does photon (or "existence" of a photon) come from?
Harvey, how would you answer this question? Is photon (and other "stuff" as you like to say) simply "exist" out there? Or its existence is a consequence of math?