For The People Who Are Still Alive

Max Teg­mark ob­served that we have three in­de­pen­dent rea­sons to be­lieve we live in a Big World: A uni­verse which is large rel­a­tive to the space of pos­si­bil­ities. For ex­am­ple, on cur­rent physics, the uni­verse ap­pears to be spa­tially in­finite (though I’m not clear on how strongly this is im­plied by the stan­dard model).

If the uni­verse is spa­tially in­finite, then, on av­er­age, we should ex­pect that no more than 10^10^29 me­ters away is an ex­act du­pli­cate of you. If you’re look­ing for an ex­act du­pli­cate of a Hub­ble vol­ume—an ob­ject the size of our ob­serv­able uni­verse—then you should still on av­er­age only need to look 10^10^115 lightyears. (Th­ese are num­bers based on a highly con­ser­va­tive count­ing of “phys­i­cally pos­si­ble” states, e.g. pack­ing the whole Hub­ble vol­ume with po­ten­tial pro­tons at max­i­mum den­sity given by the Pauli Ex­clu­sion prin­ci­ple, and then al­low­ing each pro­ton to be pre­sent or ab­sent.)

The most pop­u­lar cos­molog­i­cal the­o­ries also call for an “in­fla­tion­ary” sce­nario in which many differ­ent uni­verses would be eter­nally bud­ding off, our own uni­verse be­ing only one bud. And fi­nally there are the al­ter­na­tive de­co­her­ent branches of the grand quan­tum dis­tri­bu­tion, aka “many wor­lds”, whose pres­ence is un­am­bigu­ously im­plied by the sim­plest math­e­mat­ics that fits our quan­tum ex­per­i­ments.

Ever since I re­al­ized that physics seems to tell us straight out that we live in a Big World, I’ve be­come much less fo­cused on cre­at­ing lots of peo­ple, and much more fo­cused on en­sur­ing the welfare of peo­ple who are already al­ive.

If your de­ci­sion to not cre­ate a per­son means that per­son will never ex­ist at all, then you might, in­deed, be moved to cre­ate them, for their sakes. But if you’re just de­cid­ing whether or not to cre­ate a new per­son here, in your own Hub­ble vol­ume and Everett branch, then it may make sense to have rel­a­tively lower pop­u­la­tions within each causal vol­ume, liv­ing higher qual­ities of life. It’s not like any­one will ac­tu­ally fail to be born on ac­count of that de­ci­sion—they’ll just be born pre­dom­i­nantly into re­gions with higher stan­dards of liv­ing.

Am I sure that this state­ment, that I have just emit­ted, ac­tu­ally makes sense?

Not re­ally. It dab­bles in the dark arts of an­throp­ics, and the Dark Arts don’t get much murk­ier than that. Or to say it with­out the chaotic in­ver­sion: I am stupid with re­spect to an­throp­ics.

But to ap­ply the test of sim­plifi­a­bil­ity—it seems in some raw in­tu­itive sense, that if the uni­verse is large enough for ev­ery­one to ex­ist some­where, then we should mainly be wor­ried about giv­ing ba­bies nice fu­tures rather than try­ing to “en­sure they get born”.

Imag­ine tak­ing a sur­vey of the whole uni­verse. Every plau­si­ble baby gets a lit­tle check­mark in the “ex­ists” box—ev­ery­one is born some­where. In fact, the to­tal pop­u­la­tion count for each baby is some­thing-or-other, some large num­ber that may or may not be “in­finite” -

(I should men­tion at this point that I am an in­finite set athe­ist, and my main hope for be­ing able to main­tain this in the face of a spa­tially in­finite uni­verse is to sug­gest that iden­ti­cal Hub­ble vol­umes add in the same way as any other iden­ti­cal con­figu­ra­tion of par­ti­cles. So in this case the uni­verse would be ex­po­nen­tially large, the size of the branched de­co­her­ent dis­tri­bu­tion, but the spa­tial in­finity would just fold into that very large but finite ob­ject. And I could still be an in­finite set athe­ist. I am not a physi­cist so my fond hope may be ruled out for some rea­son of which I am not aware.)

- so the first ques­tion, an­throp­i­cally speak­ing, is whether mul­ti­ple re­al­iza­tions of the ex­act same phys­i­cal pro­cess count as more than one per­son. Let’s say you’ve got an up­load run­ning on a com­puter. If you look in­side the com­puter and re­al­ize that it con­tains triply re­dun­dant pro­ces­sors run­ning in ex­act syn­chrony, is that three peo­ple or one per­son? How about if the pro­ces­sor is a flat sheet—if that sheet is twice as thick, is there twice as much per­son in­side it? If we split the sheet and put it back to­gether again with­out desyn­chro­niz­ing it, have we cre­ated a per­son and kil­led them?

I sup­pose the an­swer could be yes; I have con­fessed my­self stupid about an­throp­ics.

Still: I, as I sit here, am fran­ti­cally branch­ing into ex­po­nen­tially vast num­bers of quan­tum wor­lds. I’ve come to terms with that. It all adds up to nor­mal­ity, af­ter all.

But I don’t see my­self as hav­ing a lit­tle util­ity counter that fran­ti­cally in­creases at an ex­po­nen­tial rate, just from my sit­ting here and split­ting. The thought of split­ting at a faster rate does not much ap­peal to me, even if such a thing could be ar­ranged.

What I do want for my­self, is for the largest pos­si­ble pro­por­tion of my fu­ture selves to lead eu­daimonic ex­is­tences, that is, to be happy. This is the “prob­a­bil­ity” of a good out­come in my ex­pected util­ity max­i­miza­tion. I’m not con­cerned with hav­ing more of me—re­ally, there are plenty of me already—but I do want most of me to be hav­ing fun.

I’m not sure whether or not there ex­ists an im­per­a­tive for moral civ­i­liza­tions to try to cre­ate lots of happy peo­ple so as to en­sure that most ba­bies born will be happy. But sup­pose that you started off with 1 baby ex­ist­ing in un­happy re­gions for ev­ery 999 ba­bies ex­ist­ing in happy re­gions. Would it make sense for the happy re­gions to cre­ate ten times as many ba­bies lead­ing one-tenth the qual­ity of life, so that the uni­verse was “99.99% sorta happy and 0.01% un­happy” in­stead of “99.9% re­ally happy and 0.1% un­happy”? On the face of it, I’d have to an­swer “No.” (Though it de­pends on how un­happy the un­happy re­gions are; and if we start off with the uni­verse mostly un­happy, well, that’s a pretty un­pleas­ant pos­si­bil­ity...)

But on the whole, it looks to me like if we de­cide to im­ple­ment a policy of rou­tinely kil­ling off cit­i­zens to re­place them with hap­pier ba­bies, or if we lower stan­dards of liv­ing to cre­ate more peo­ple, then we aren’t giv­ing the “gift of ex­is­tence” to ba­bies who wouldn’t oth­er­wise have it. We’re just set­ting up the uni­verse to con­tain the same ba­bies, born pre­dom­i­nantly into re­gions where they lead short lifes­pans not con­tain­ing much hap­piness.

Once some­one has been born into your Hub­ble vol­ume and your Everett branch, you can’t undo that; it be­comes the re­spon­si­bil­ity of your re­gion of ex­is­tence to give them a happy fu­ture. You can’t hand them back by kil­ling them. That just makes their av­er­age lifes­pan shorter.

It seems to me that in a Big World, the peo­ple who already ex­ist in your re­gion have a much stronger claim on your char­ity than ba­bies who have not yet been born into your re­gion in par­tic­u­lar.

And that’s why, when there is re­search to be done, I do it not just for all the fu­ture ba­bies who will be born—but, yes, for the peo­ple who already ex­ist in our lo­cal re­gion, who are already our re­spon­si­bil­ity.

For the good of all of us, ex­cept the ones who are dead.