In the first half of the 14th century, the Franciscan friar and logician, William of Occam proposed a heuristic for deciding between alternative explanations of physical observables. As William put it: "Entities should not be multiplied without necessity". Or, as Einstein reformulated it 600 years later: "Everything should be made as simple as possible, but not simpler".
Occam's Razor, as it became known, was enthusiastically adopted by the scientific community and remains the unquestioned criterion for deciding between alternative hypotheses to this day. In my opinion, its success is traceable to two characteristics:
o Utility: OR is not a logical deduction. Neither is it a statement about which hypothesis is most likely. Instead, it is a procedure for selecting a theory which makes further work as easy is possible. And by facilitating work, we can usually advance further and faster.
o Combinability. OR is fully compatible with each the epistemological stances which have been adopted within science from time to time (empiricism, rationalism, positivism, falsifiability, etc.)
It is remarkable that such a widely applied principle is exercised with so little thought to its interpretation. I thought of this recently upon reading an article claiming that the multiverse interpretation of quantum mechanics is appealing because it is so simple. Really?? The multiverse explanation proposes the creation of an infinitude of new universes at every instant. To me, that makes it an egregiously complex hypothesis. But if someone decides that it is simple, I have no basis for refutation, since the notion of what it means for a theory to be simple has never been specified.
What do we mean when we call something simple? My naive notion is to begin by counting parts and features. A milling device made up of two stones, one stationary one mobile, fitted with a stick for rotation by hand becomes more complex when we add devices to capture and transmit water power for setting the stone in motion. And my mobile phone becomes more complex each time I add a new app. But these notions don't serve to answer the question whether Lagrange's formulation of classical mechanics, based on action, is simpler than the equivalent formulation by Newton, based on his three laws of forces.
Isn't remarkable that scientists, so renown for their exactitude, have been relying heavily on so vague a principle for 700 years?
Can we do anything to make it more precise?
First, can you define "SWE"? I'm not familiar with the acronym.
Second, why is that a problem? You should want a theory that requires as few assumptions as possible to explain as much as possible. The fact that it explains more than just your point of view (POV) is a good thing. It lets you make predictions. The only requirement is that it explains at least your POV.
The point is to explain the patterns you observe.
It most certainly is. If you try to run the Copenhagen interpretation in a Turing machine to get output that matches your POV, then it has to output the whole universe and you have to find your POV on the tape somewhere.
The problem is: That's not how theories are tested. It's not like people are looking for a theory that explains electromagnetism and why they're afraid of clowns and why their uncle "Bob" visited so much when they were a teenager and why their's a white streak in their prom photo as though a cosmic ray hit the camera when the picture was taken, etc. etc.
The observations we're talking about are experiments where a particular phenomenon is invoked with minimal disturbance from the outside world (if you're lucky enough to work in a field like Physics which permits such experiments). In a simple universe that just has an electron traveling toward a double-slit wall and a detector, what happens? We can observe that and we can run our model to see what it predicts. We don't have to run the Turing machine with input of 10^80 particles for 13.8 billion years then try to sift through the output tape to find what matches our observations.
Same thing for the Many Worlds interpretation. It explains the results of our experiments just as well as Copenhagen, it just doesn't posit any special phenomenon like observation, observation is just what entanglement looks like from the perspective of one of the entangled particles (or system of particles if you're talking about the scientist).
First of all: Of course you can use many worlds to make predictions, You do it every time you use the math of QFT. You can make predictions about entangled particles, can't you? The only thing is: while the math of probability is about weighted sums of hypothetical paths, in MW you take it quite literally as paths the actually being traversed. That's what you're trading for the magic dice machine in non-deterministic theories.
Secondly: Just because Many Worlds says those worlds exist, doesn't mean you have to invent some extra phenomenon to justify renormalization. At the end of the day the unobservable universe is still unobservable. When you're talking about predicting what you might observe when you run experiment X, it's fine to ultimately discard the rest of the multiverse. You just don't need to make up some story about how your perspective is special and you have some magic power to collapse waveforms that other particles don't have.
Please stop introducing obscure acronyms without stating what they mean. It makes your argument less clear. More often than not it results in *more* typing because of the confusion it causes. I have no idea what this sentence means. SU&C = Single Universe and Collapse? Like objective collapse? "Different" what?