the quantum amplitude argument against ethics deduplication

Note that if you subscribe to MWI, the whole thing is completely deterministic, and so you can't decide to pour different amounts of this "existence juice" into different "branches" by making smarter decisions about AI research. The outcome was predetermined at the time the universe was created. All you do is LARP until the reality reveals itself.

with regards to intrinsic value (rather than eg caring about diversity)

Do you have a reference (or sketch of an argument) for why there's any such thing as "intrinsic value", and why diversity or variety wouldn't be part of it?

with regards to intrinsic value (rather than eg caring about diversity), duplicating the computation of moral-patient-experience does count as more moral-patient-experience. in deduplication ethics, I≈M≈Q≈V.

The physics doesn't determine the intrinsic value of anything, and what you care calling intrinsic value is not intrinsic.

The physics also doesn't tell you how measure -- what you are calling "reality juice" -- relates to consciousness. Having levels of consciousness that decrease with decreasing measure is convenient for some ethical theories, but you shouldn't believe things because they are convenient. Also, it's a kind of zombie argument.

There's broadly two areas where MWI has ethical implications. One is over the fact that MW means low probability events have to happen very time -- as opposed to single universe physics, where they usually don't. The other is over whether they are discounted in moral significance for being low in quantum mechanical measure or probability

It can be argue that probability calculations come out the same under different interpretations of QM, but ethics is different. The difference stems from the fact that what what other people experience is relevant to them, wheareas for a probability calculation, I only need to be able to statistically predict my own observations. Using QM to predict my own observations, I can ignore the question of whether something has a ten percent chance of happening in the one and only world, or a certainty of happening in one tenth of possible worlds.

You can have objective information about observations, and if your probability calculus is wrong , you will get wrong results and know that you are getting wrong results. That is the negative feedback that allows physics to be less wrong.

You can have subjective information about your own mental states, and if your personal calculus is wrong , you will get wrong results and know that you are getting wrong results. That is the negative feedback that allows personal decision theory to be less wrong.

Altruistic ethics is different. You don't have either kind of direct evidence, because you are concerned with other people's subjective sensations , not objective evidence , or your own subjectivity. Questions about ethics are downstream of questions about qualia, and qualia are subjective, and because they are subjective, there is no reason to expect them to behave like third person observations. We have to infer that someone else is suffering , and how much, using background assumptions. For instance, I assume that if you hit your thumb with a hammer , it hurts you like it hurts me when I hit my thumb with a hammer.

One can have a set of ethical axioms saying that I should avoid causing death and suffering to others, but to apply them under many worlds assumptions, I need to be able to calculate how much death and suffering my choices cause in relation to the measure. Which means I need to know whether the measure or probability of a world makes a difference to the intensity of subjective experience.. including the option of "not at all", and I need to know whether the deaths of then people in a one tenth measure world count as ten deaths or one death. .

Suppose they are discounted.

If people in low measure worlds experience their suffering fully, then a 1%, of creating a hell-world would be equivalent in suffering to a 100% chance. But if people in low measure worlds are like philosophical zombies, with little or no phenomenal consciousness, so that their sensations are faint or nonexistent, the moral hazard is much lower.

A similar, but slightly less obvious argument applies to causing death. Causing the "death" of a complete zombie is presumably as morally culpable as causing the death of a character in a video game...which, by common consent, is not problem at all. So... causing the death of a 50% zombie would be only half as bad as killing a real person...maybe.

There is an alternative way of cashing out quantum mechanical measure due to David Deutsch. He supposes that you can have exact duplicates of worlds , which form sets of identical worlds, and which have no measure of their own. Each set contains different worlds, making the sets unique, each world within a set is identical to the others. Counting the worlds in an equivalence set gives you the equivalent of measure.

Under this interpretation, you should ethically discount low-measure worlds (world sets) because there are fewer people in them.

The approach where suffering and moral worth are discounted according to measure has the convenient property that it works like probability theory, so that you don't have to take an interpretation of QM into account. But , if you are arguing to the conclusion that the interpretation of QM is ethically neutral, you can't inject the same claim as an assumption, without incurring circularity.

What's needed is a way of deciding the issue of measure versus reality versus consciousness ethical value that is not question begging. We are not going to get a rigourous theory based on physics alone, because physics does not explicitly deal with reality, consciousness or ethical value. But there are some hints. One important consideration is that under many world's theory, all worlds must have measures summing to 1, so any individual world,including ours, has measure less than 1. But our world and our consciousness seem fully real to us; if there is nothing special about our world, then the inhabitants of other worlds presumably feel the same. And that is just the premise that leads to the conclusion that many world's theory does impact ethics.

I don't buy the anthropic interpretation for the same reason I don't buy quantum immortality or grabby aliens, so I'm still weakly leaning towards thinking that decoherence matters. Weirdly I haven't seen this dilemma discussed before, and I've not brought it up because I think it's ifonharazdous--for the same reasons you point out in the post. I also tried to think of ways to exploit this for moral gain two years ago! So I'm happy to see I'm not the only one (e.g., you mention entropy control).

I was going to ask a question, but I went looking instead. Here's my new take:

After some thinking, I now have a very shoddy informal mental model in my head, and I'm calling it the "Quantum Shuffle Theory" ⋆★°. If (de)coherence is based on a local measure of similarity between states, then you'd likely see spontaneous recoherence in regions that line up. It could reach equilibrium if the rate of recoherence is a function of decoherence (at some saturation point for decohered configurations).

Additionally, the model (as it works in my head at least) would predict that reality fluid isn't both ergodic and infinite, because we'd observe maxed out effects of interference literally everywhere all the time (although maybe that's what we observe, idk). Or, at least, it puts some limits on how the multiverse could be infinite.

Some cherry-picked support I found for this idea:

"Next, we show that the evolution of the pure-basis states reveals an interesting phenomenon as the system, after decoherence, evolves toward the equilibrium: the spontaneous recoherence of quantum states. ... This phenomenon reveals that the reservoir only shuffle the original information carried out by the initial state of the system instead of erasing it. ... Therefore, spontaneous recoherence is not a property associated only with coherent-state superpositions." (2010)

Also, Bose-Einstein condensates provide some evidence for the shuffling interpretation, but my qm is weak enough that idk whether bog standard MWI predicts it too.

"a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero (−273.15 °C or −459.67 °F). Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which point microscopic quantum mechanical phenomena, particularly wavefunction interference, become apparent macroscopically."