If you commit to the multiverse being physical, by extension you're making claims about ontological concerns, since all physical claims require there to be a notion of something existing, even if you're wanting to claim that something counterfactually exists. Then that gets into modal realism etc etc.

Likewise you can't be fully confident in multiversal theories since no physicist endorses a multiversal theory without also accepting it as interpretative, as no experiment has been performed to anoint multiversal theories as being correct. So you're still postulating something worthy of criticism even if there was nothing ontological involved.

Notice that none of this prevents there from being a singular subject that we can talk about, but there can still be substantial disagreement as to the nature of the thing be discussed. If we are disputing whether or not there is a multiverse I would just ask you, what are your grounds for accepting that we occupy a multiverse and what brought you to do so?

I'm not familiar with this point; is this a reference to model theory? Can you explain or provide a reference to this stuff?

I'm leaning on the fact that theories are significations of events, but significations are only possible when relative to an interpretive scheme that allows those events to be connected to the theory.

A deep-math version of this would be picking whether or not you want to work with the axiom of choice or not when using groups to represent vectors (the groups and vectors aren't important here, but they play the role of theories and objects). Deciding whether or not you accept the axiom of choice can a have major impact on what theorems you are willing to accept as justifiable, but the decision is not purely aesthetical, because it's possible to have technical reasons for using the axiom of choice.

Resolving whether or not the axiom of choice for the purposes of your practice can be done but it won't usually be within the scope of the system. Often you need to introduce further information from outside the system to justify use of the axiom. And so you are building on further postulates, making more choices at the exclusion of others.

A more science-y example: It can be seen as a restatement of the Duhem-Quine thesis: you always need postulates to relate a hypothesis to its observation. These postulates might correspond to truth or might not but you are almost working with a set of assumptions with varying levels of validation when doing any scientific work. https://en.wikipedia.org/wiki/Duhem%E2%80%93Quine_thesis

All of this drives out from philosophical school of American Pragmatism, which includes philosophers like Charles Peirce and Charles Morris who pioneered the semiotic theory. To a lesser extent Carnap might fit in this category since he bought the semantics/syntactics/pragmatics distinction that Peirce and Morris created, then set up classical logic as we know it (including model theory), although he's usually considered a positivist.

The point of all of the above is to realize that modern philosophy has made three different "turns":

1) The linguistic turn

2) The pragmatic turn

3) The discursive turn

All three point to the idea that almost all acts of knowledge are social and communicative acts, and that all claims being made between us are from perspectives we assume and inherit from others. They amount to saying that no inquiry is done in a vacuum, and all inquiry is open to criticism of some form or another. In which case we shouldn't expect to ever converge on a singular Truth, but rather be constantly negotiating a network of truths between ourselves as long as we are finite and limited beings.

These positions are reactions to middle-of-the-century philosophy that supposed that all knowledge can be treated through a uniform standard (like science, or logic, or faith), and that any knowledge which is true, is true without qualification or the need to ascribe context, including the context of our language or the context of our goals. Both of these positions can be considered "positivist", which is the philosophy that made physics productive in the 20th century but ended up being unhelpful for other fields (like economics or biology), as well as ignoring certain complexities that all forms of inquiry (including physics) share.

The primary struggle that positivists gain when they are exposed to these views is that they think it implies relativism. This isn't quite right, since it's possible to agree as well as disagree with people; but it does imply certain theses inconvenient to the goals of positivism, like the impossibility of a final theory between all modes of knowledge. It might be plausible to have a final theory with respect to a perspective or set of postulates -- like maybe an atomic theory of viruses -- but that would always be irreconcilable with other perspectives which have their own merits, leaving it to the individual to decide the value of each. The good news is that there is always room for thought.

This paper is also excellent for introducing the mechanics of semiotics in discourse, in that most discursive of disciplines, the Law. https://pdfs.semanticscholar.org/0a7f/1fd305239da9232f182fbc... Law makes a good example since people have a lot of conceptions of what having rules of law means. We are obliged to the law by convention and negotiation, rather than by some eternal Truth. Likewise, to the extent that any science is discursive, there will be a sense in which it has to be legalistic, although there are more effective ways which we stop ourselves from spiraling into relativism here (primarily by instrumentation).

If you are willing to wait a bit I can get back to you on this once I have an email account.

The article seems to argue that since a digital system can simulate an analog system (through a DAC), reality cannot be either digital nor analog. But that doesn't matter, since as long a reality can simulate digital or analog phenomena, it can simulate the digital phenomena and create Turing machines.

The link to "A Defence of Informational Structural Realism" is broken.

But saying that the laws of physics specifically lend themselves to computers involves finding reasons that this may be so.

Yet if there is no inherent computational property in physical nature (like say that the laws actually reflect cellular automata, or are fully deterministic and are not nominal), then we ought to be skeptical that Turing Machines are somehow essential to physics or physical constraints, or that we should be surprised if Turing Machines are common.

Maybe Turing Machines are common just because the definition of a Turing Machine is syntactically weak.

More general statements about evolution (the kind that I'm guessing Universal Darwinists endorse) would be uninteresting to me because they begin to eliminate details about the system which would render the claims less trivial to talk about... although, I know that there are serious theorists of self-organization that might be better equipped to understand how to talk about fundamental truths of this kind (like Stuart Kauffman).

I'd be less combative in this thread if there were discussions about the ways in which Turing-Completeness come about in the different realizations of the machine, or if comparisons were made between these machines. But so far there hasn't been a lot to prove.

I recommend this extension: https://unpaywall.org/

Edit: page 7 discusses some of the points I complained about, but it does not seem particularly convincing to me (it only brushes them off, without explaining them). Admittedly, the language of philosophy is frequently unconvincing to me, so maybe the problem is in me.