Status Updates From The Principles of Quantum T...

[Personally I prefer a realist approach, at least on some fundamental level, because its the only way to stop our core correct science from gradually floating away into flights of fancy disconnected from reality. Not only that nonrealist tendencies strengthen the kinds of irrational pushing of fashion in science regardless of empirical reality, such as in string theory, becoming a kind of elitist glass bead game.]

According to the nonrealist argumentation offered by this study, such notions, more radically, bear no resemblance to this reality at all, a reality that in the first place cannot be perceived, but is only assumed, inferred from realities that we can perceive. (This, strangely seems to cross over a lot with the kind of selective subjectivism that Eddington was/is proposing.)

The program and the way of pursuing it harmonize with my argument in this book, applied to quantum theory, especially the point “that the
notions needed to understand perceived reality may bear little resemblance to it.”

..This situation reflects the fact that what happens is unavoidably defined by what kinds of experiments we perform, and how we affect quantum objects, rather than only by their independent behavior, although their independent behavior does of course contribute to what happens.

I briefly recapitulate the nature of this transformation here. The practice of experimental physics does not consist of tracking what happens or what would have happened independently of our experimental technology, but in creating, again, unavoidably creating, configurations of this technology...

As discussed in Chap. 2, Heisenberg’s thinking, thus, revolutionized the very practice of theoretical physics, and it redefined experimental physics as well, or reflected what the practice of experimental physics had in fact already become by that point..

Well no doubt if you have put the numbers in by hand experimentally then the numbers you are going to get will be very accurate!! Given all the theory does is put these numbers in based on their experimental values. The problem is that you have no "confirmation", here of some theory, just description of an empirical procedure with no theory.

...These calculations are, again, experimentally confirmed to a very high degree. As already noted, quantum electrodynamics is the best experimentally confirmed theory thus far..

[The cognitive dissonance here is bizarre. In one sentence he says the experimental numbers are put in by hand, and then in the very next sentence he says this is experimentally confirmed!!!]

(Regarding Renormalisation)

At a certain stage of calculation, however, these integrals are replaced by finite integrals through artificial cut-offs that have no proper mathematical justification within the formalism and are performed by putting in, by hand, experimentally obtained numbers that make these integrals finite, which removes the infinities from the final results of calculations...

As indicated earlier, one could, in principle, think of the virtual of a quantum field as what J. A. Wheeler called “quantum foam,” whereby the classical picture of matter as a motion of particles or waves is replaced by that of incessant birth and disappearance of quantum entities..

The qualification that virtual particles are never actually observed is crucial. Only those particles that are registered by observation are considered “real particles,” while “virtual particles” are never registered by observation. “Actual” may, again, be a more accurate term than real,” because virtual particles are as real as actual particles. [In what way are they real? Not the normal way as are not observed

How are you securing their reality without realism based on merely linguistic designations. You need to clarify and distinguish here what you mean by "realism" and "reality" that allows you to do this. Appealing to operationalism is not enough.

The present concept is, by contrast, nonrealist, even though it assumes the reality—reality without realism—of quantum fields, as an instance of Bohr’s concept of a quantum object as something that is unavailable to a representation or..., even conception. This view, again, makes the term “quantum objects” merely a linguistic designation not associated to any specifiable concept. [Reality without realism?]

Elementary particles, and their reality, could be seen not in terms of their realist representations or even conception, but in technological terms of particular types of effects of their interactions with measuring instruments, effects that we can predict, probabilistically or statistically, by using quantum theory. [Operationalism, no realism, no particles]

In QFT, it is as if instead of identifiable moving objects and motions of the type studied in classical physics, we encounter a continuous emergence and disappearance, creation and annihilation, of particles, theoretically governed by the concept of virtual particle formation.