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One world is good, so two is better, right?

(If you think one world is bad and two are worse, just invert the reflections below.)

Here's one way to look at it: Run a universe, or a world, from beginning to end, sum up all the good stuff, subtract all the bad stuff, and note the (hopefully positive) total. Now consider, from your end-of-the-universe God's-eye point of view: Should you launch another world similar to the previous one? Well, of course you should! There would be even more good stuff, and a higher positive total, after that second world has been run. Similar considerations suggest that two good worlds running in parallel would also be better than a single good world.

Now on some interpretations of quantum mechanics, every time there's a quantum event with different possible outcomes, all of the outcomes occur, each in a different world. Such "many world" interpretations often describe the world as "splitting" into two worlds -- one world in which Outcome A occurs and one in which Outcome B occurs. You too, the observer, will split: One copy of you goes into World A, observing Outcome A, and the other goes into World B, observing Outcome B.

In a classic article on the many-worlds interpretation of quantum mechanics, Bryce S. DeWitt writes:

This universe is constantly splitting into a stupendous number of branches, all resulting from the measurementlike interactions between its myriads of components. Moreover, every quantum transition taking place on every star, in every galaxy, in every remote corner of the universe is splitting our local world on earth into myriads of copies of itself.... I still recall vividly the shock I experienced on first encountering this multiworld concept. The idea of 10^100+ slightly imperfect copies of oneself all constantly splitting into further copies, which ultimately become unrecognizable.... (DeWitt 1970, p. 33).

Notice that on DeWitt's portrayal, there are a finite but large number of worlds: 10^100+. Now here's the normative question I want to consider: Is there positive value -- would it be ethically or prudentially or aesthetically good -- to increase the amount of splitting, so that there are more worlds rather than fewer?

On the face of it, it seems that, yes, it would be good if there were more worlds. If each world independently considered is good, then plausibly more worlds is better. Suppose World W has positive value V. Suppose now that it splits into two worlds that are very similar but not identical: W1 with value V1 and W2 with value V2. If we assume V1 ~= V2 ~= V and that the value of worlds is additive, then after the split the whole W1+W2 is approximately twice the value of W. We have doubled the amount of value that the cosmos as a whole contains!

Now you might object in one of three ways:

(1.) You might reject the whole splitting-worlds interpretation. Fair enough! But then you're not really playing the game. I'm interested in thinking about the normative consequences assuming that the world does split as DeWitt describes.

(2.) You might reject the assumption that V1 ~= V. For example, you might think that after splitting, each world has only approximately half the value that the world before the split had, so that V1 + V2 ~= V. Then no value would be gained by splitting. A tempting thought, perhaps. But why would splitting make a world half as valuable? It's not clear. One consequence of this view is that our world, constantly splitting, would be constantly halving in value, so that its value is plummeting by orders of magnitude every second. Hmmm, that seems no less bizarre than the idea that splitting doubles the value of cosmos. Now if you thought that the other worlds already existed before the split, then you might reject V1 ~= V, since the subset of worlds in V1 would be about half (or whatever) of the total number of worlds in V. But the whole idea of splitting worlds is not that the worlds already existed. It's that they are created. So we're talking about whether creating a new valuable world adds value to the cosmos as a whole. Pending a good argument otherwise, it seems like it should.

(3.) You might reject additivity. You might say that although V1 ~= V2 ~= V, you can't simply sum V1 and V2 to get ~= 2V. I can feel the pull of this idea. If the worlds were strictly identical, you might say "well, there's no point in duplicating everything again"! But (a.) The worlds are not strictly identical, and in fact (given chaos theory) they might diverge increasingly over time. And (b.) Duplication plausibly adds value when worlds are temporally separated (at the end of the universe, it seems like not re-running the thing again would involve omitting possible future pleasures that future inhabitants of the world would have), and side-by-side splitting wouldn't seem to be very normatively different in principle.

Okay, let's pretend you're convinced. When new worlds arise through quantum mechanical splitting, that's terrific. Whole realms of value are added! The value of the cosmos as a whole approximately doubles. Now, accepting this, is there anything you should do differently?

Consider the following possible principle:

Conservation of Splitting. Over any time interval t, the world will split N times, no matter what you do.

As far as I can see, there's no reason to accept Conservation of Splitting. It seems like you can create situations in which there would be relatively more splitting or relatively less splitting. You can run more quantum mechanical experiments or fewer. You can make more quantum mechanical measurements or fewer. And if you run more experiments and make more measurements, there will be more splitting, and thus more worlds.

For example, that pair of polarized sunglasses you have, sitting in that dark sunglass case in that dark drawer? When a photon passes or fails to pass through a polarized lens, that's a quantum mechanical event -- a chance event, which, on this interpretation, results in a splitting of worlds. In some worlds the photon goes through; in others it does not. You could take those sunglasses out of the drawer. You could go to the beach and wear them in the sun. Many more photons will pass through those lenses! Maybe about 10^18 more photons per second. If each of those photons has an independent quantum chance of passing or not passing through those lenses, splitting the world, then you're creating 2^10^18 new worlds per second just by sitting on the beach -- worlds that would not have been created had the sunglasses remained cased in the drawer. Think of all the value you're adding to the cosmos!

Effective altruism is a movement that recommends using reason and evidence to do the most good you can do. Normally, effective altruists recommend doing things like donating money to charities that effectively help to alleviate suffering due to poverty. But the value of saving one life has to be tiny compared to the value of creating 2^10^18 new universes per second! So instead of staying indoors in the shade, writing a check to the Against Malaria Foundation, maybe you'd do better to spend the day at the beach.

Even if you have only a 0.001% credence that the splitting worlds interpretation of quantum mechanics is true, the expected utility of sitting on the beach might far exceed that of donating to poverty relief.

I know that it doesn't seem intuitively very plausible that going to the beach is far morally better than donating money to effective, life-saving charities, but consequentialist philosophers are often willing to admit what's ethically best might not match our intuitions about what's ethically best.

Eric Schwitzgebel

http://schwitzsplinters.blogspot.com/2018/07/how-to-create-immensely-valuable-new.html