jessicata

Jessica Taylor. CS undergrad and Master's at Stanford; former research fellow at MIRI.

I work on decision theory, social epistemology, strategy, naturalized agency, mathematical foundations, decentralized networking systems and applications, theory of mind, and functional programming languages.

Many-worlds versus discrete knowledge

Thanks! To the extent that discrete branches can be identified this way, that solves the problem. This is pushing the limits of my knowledge of QM at this point so I'll tag this as something to research further at a later point.

Many-worlds versus discrete knowledge

I'm not asking for there to be a function to the entire world state, just a function to observations. Otherwise the theory does not explain observations!

(aside: I think Bohm does say there is a definite answer in the cat case, as there is a definite configuration that is the true one; it's Copenhagen that fails to say it is one way or the other)

Many-worlds versus discrete knowledge

Then you need a theory of how the continuous microstate determines the discrete macrostate. E.g. as a function from reals to booleans. What is that theory in the case of the wave function determining photon measurements?

Many-worlds versus discrete knowledge

I'm saying that our microphysical theories should explain our macrophysical observations. If they don't then we toss out the theory (Occam's razor).

Macrophysical observations are discrete.

Many-worlds versus discrete knowledge

Let me know if anyone succeeds at that. I've thought in this direction and found it very difficult.

Many-worlds versus discrete knowledge

See my reply here.

Consistent histories may actually solve the problem I'm talking about, because it discusses evolving configurations, not just an evolving wave function.

Many-worlds versus discrete knowledge

The wave function is a fluid in configuration space that evolves over time. You need more theory than that to talk about discrete branches of it (configurations) evolving over time.

I agree that once you have this, you can say the knowledge gained is indexical.

Many-worlds versus discrete knowledge

It's rather nonstandard to consider things like photon measurements to be nonphysical facts. Presumably, these come within the domain of physical theories.

Suppose we go with Solomonoff induction. Then we only adopt physical theories that explain observations happening over subjective time. These observations include discrete physical measurements.

It's not hard to see how Bohm explains these measurements: they are facts about the true configuration history.

It is hard to see how many worlds explains these measurements. Some sort of bridge law is required. The straightworward way of specifying the bridge law *is* the Bohm interpretation.

Many-worlds versus discrete knowledge

Yes the argument has to be changed but that's mostly an issue of wording. Just replace discrete knowledge with discrete factual evidence.

If a Bayesian sees that the detector has detected a photon, how is that evidence about the wave function?

The basic point here is that Bayesians lose zero sum games in the long term. Which is to be expected, because Bayesianism is a non adversarial epistemology. (Adversarial Bayesianism is simply game theory)

This sentence is surprising, though: "It is a truth more fundamental than Bayes’ Law that money will flow from the unclever to the clever".

Clearly, what wins zero sum games wins zero sum games, but what wins zero sum games need not correspond to collective epistemology.

As a foundation for epistemology, many things are superior to "might makes right", including Bayes' rule (despite its limitations).

Legislating Bayesianism in an adversarial context is futile; mechanism design is what is needed.