There is both the "interference pattern" on the target wall made by individual photons over time, which we can directly observe, and the interference of the pho

There is both the "interference pattern" on the target wall made by individual photons over time, which we can directly observe, and the interference of the photon's wavefunction with itself, which we cannot directly observe. I was referring to the former. We know the photon interferes with itself, via the wavefunction as you describe, but this interaction is entirely unobservable and invisible to us, and in that sense, we don't understand the ontological status of the wavefunction and what it's physical status is.