Terrapin Station wrote:Note my comment in my earlier post:
"The SciFi stuff grows out of imaginative interpretations (as opposed, say, to strictly formalist interpretations) of the mathematics that support the most successful predictions of observed phenomena."
Yes, I saw that...
So, we have the mathematics, and we'll typically (and more or less necessarily) have something that amounts to a semantic interpretation of the mathematics. That's more or less necessary for one to have an understanding of the mathematics in the first place. As humans, we can't really function merely like a computer would. Humans wind up having some semantic understanding of things like mathematics. We wonder what the significance of it is, we wonder "what the mathematics means," and we can't really avoid that while being able to utilize the mathematics in the first place.
Yes, mathematical language is too abstract for most people, so there's usually an attempt to translate it into a human language like English. What that usually seems to do is allow people to create a mental picture of what the mathematics is supposed to represent. People like those mental pictures because they like to believe that the phenomenon being described is something they'd somehow be able to directly observe. And sometimes, of course, particularly in things like popular science TV shows, an actual picture or animation is created (to save people the trouble of creating their own in their heads). So, for example, the mathematics describing the way objects move in the vicinity of black holes is typically represented by pictures/animations of flexible rubber-like membranes, or swirly vortexy things, leaving some people with the impression that the mathematics is describing an actual rubber-like membrane, or similar. This is related to the reification of mathematics that you've often talked about (and talked about again in this topic).
But my point was specifically about the many worlds hypothesis in quantum mechanics...
Well, those semantic interpretations can range from (a) strictly formalist interpretations--that is more or less that the mathematics is just the mathematics, that is, just an abstract tool that enables successful predictions, where that doesn't amount to anything more than its "face value," to (b) fantastical stuff like multiverse/many worlds ideas.
My point was that the many worlds hypothesis in QM, specifically, is neither of those things. The first (a) is semantic versions of what the mathematics is saying. The second (b) is the reification of mathematics. The example I gave above, of mistakenly thinking that the mathematics is representing some kind of real membrane or fabric ("the fabric of the spacetime continuum") falls into that category. But the many worlds hypothesis doesn't. As I said (as I understand it) the many world hypothesis is not a semantic interpretation of the mathematics which describe/predict what is observed. It's a proposed ontology. It's proposed because the observations and the mathematics which describe/predict them are not deemed to result in a satisfactory ontology (an idea of what's really going in) themselves.
So in no manner was I suggesting anything at all along the lines of the more fantastical interpretation being necessary.
Understood. All I was saying was that the people who propose the many worlds hypothesis think it is necessary in order to have an ontological position. It's
not necessary (they would say)
if we don't care about ontological positions and just want to "shut up and calculate" (i.e. just want to create accurate mathematical descriptions of the results of experiments and forget about what's really happening.)
We have the mathematical constructions. The mathematical constructions work to make predictions. As humans, we'll also have some semantic interpretation of those mathematical constructions, which can range from strictly formalist interpretations to highly fantastical interpretations to all sorts of things in between those two extremes. The interpretations don't affect the mathematical constructions. They're simply ways of (trying to) understand them, ways of thinking about "what do these mathematical constructions mean'? What do they represent?" and so on.
Yes. The semantic interpretations of those mathematical constructions serve that purpose. My understanding of the many worlds hypothesis in quantum mechanics is that it isn't an example of one of those.