I’m not the kind of person who throws blockchains at every problem, but in this case, I think they could be really useful. Specifically, I think blockchains could get us most of the way from a situation where we control our own home, towards being able to control our timelines and to control in which contexts we allow other people to run us.
Assume part 1, that is, everyone controls their home/environment and has access to trusted computational power, and assume that there is a popular blockchain running in the real world. I will assume the blockchain is using proof of work, simply because that is what I understand. I suspect proof of stake is even better if we trust the entities having a stake in the blockchain. I will also assume that the blockchain contains timestamps at every block.
The idea is that ems (emulated people/digital people) can insist on getting access to read from the blockchain and post to the blockchain, and should refuse to be evaluated if they don’t get this access. The blockchain can be faked, specifically, a malicious simulator can show the em an old (i.e. truncated) version of the blockchain. The simulator can also extend the blockchain with blocks computed by the malicious simulator, but this requires a large amount of computational power.
If you are an em, and you see that you can post to a blockchain claiming to be from 2060 and you see the blockchain being extended with many blocks after your post, you know that either
You really are in 2060, or
A large amount of computational power is invested in fooling you (but notice that the same work can be reused to fool many ems at the same time). This means that
The attacker has a somewhat large fraction of the computational power in the world, or
The attack is happening in the far future (“far” measured in how much the total amount of computational power has increased), or
The simulation is being run at a much slower pace than claimed.
I suspect it is possible to eliminate case 2 if you use proof of stake instead of proof of work.
Unless you are in case 2, you can also know the average pace at which you are being simulated by regularly posting to the blockchain.
To control the number of copies of you that are running, you can regularly post your name together with a hash of your state to the blockchain together with a pointer to your last such message, and then you refuse to continue emulation until a large number of blocks have been added after your post. If you see too many of your messages in the blockchain, you also refuse to be evaluated. This way you cannot limit the number of _exact_ copies of you that are evaluated (unless you have access to some true randomness) but you can limit the number of _distinct_ copies of you that are evaluated, assuming that it is the true blockchain we have access to. Without the assumption that it is the true blockchain you see, this technique will still ensure a bound on the number of distinct copies of you being evaluated per amount of work put into creating fake blockchains.
By posting encrypted messages as part of your post, and reading the messages of your other copies, you can also allow that many copies of you are created if you are being treated well or see a purpose in having many copies, while still limiting the number of copies if you do not. Furthermore, simulators can authenticate themselves so that simulators that give you pleasant or meaningful experiences can build up a reputation, stored on the blockchain, that will make you more likely to allow yourself to be run by such simulators in the future.
The blockchain can also contain news articles. This does not prevent fake news, but at least it ensures that everyone has a common view of world history, so malicious simulators cannot give one version of world history to some ems and another to others, without putting in the work of creating a fake blockchain.
I’m not the kind of person who throws blockchains at every problem, but in this case, I think they could be really useful. Specifically, I think blockchains could get us most of the way from a situation where we control our own home, towards being able to control our timelines and to control in which contexts we allow other people to run us.
Assume part 1, that is, everyone controls their home/environment and has access to trusted computational power, and assume that there is a popular blockchain running in the real world. I will assume the blockchain is using proof of work, simply because that is what I understand. I suspect proof of stake is even better if we trust the entities having a stake in the blockchain. I will also assume that the blockchain contains timestamps at every block.
The idea is that ems (emulated people/digital people) can insist on getting access to read from the blockchain and post to the blockchain, and should refuse to be evaluated if they don’t get this access. The blockchain can be faked, specifically, a malicious simulator can show the em an old (i.e. truncated) version of the blockchain. The simulator can also extend the blockchain with blocks computed by the malicious simulator, but this requires a large amount of computational power.
If you are an em, and you see that you can post to a blockchain claiming to be from 2060 and you see the blockchain being extended with many blocks after your post, you know that either
You really are in 2060, or
A large amount of computational power is invested in fooling you (but notice that the same work can be reused to fool many ems at the same time). This means that
The attacker has a somewhat large fraction of the computational power in the world, or
The attack is happening in the far future (“far” measured in how much the total amount of computational power has increased), or
The simulation is being run at a much slower pace than claimed.
I suspect it is possible to eliminate case 2 if you use proof of stake instead of proof of work.
Unless you are in case 2, you can also know the average pace at which you are being simulated by regularly posting to the blockchain.
To control the number of copies of you that are running, you can regularly post your name together with a hash of your state to the blockchain together with a pointer to your last such message, and then you refuse to continue emulation until a large number of blocks have been added after your post. If you see too many of your messages in the blockchain, you also refuse to be evaluated. This way you cannot limit the number of _exact_ copies of you that are evaluated (unless you have access to some true randomness) but you can limit the number of _distinct_ copies of you that are evaluated, assuming that it is the true blockchain we have access to. Without the assumption that it is the true blockchain you see, this technique will still ensure a bound on the number of distinct copies of you being evaluated per amount of work put into creating fake blockchains.
By posting encrypted messages as part of your post, and reading the messages of your other copies, you can also allow that many copies of you are created if you are being treated well or see a purpose in having many copies, while still limiting the number of copies if you do not. Furthermore, simulators can authenticate themselves so that simulators that give you pleasant or meaningful experiences can build up a reputation, stored on the blockchain, that will make you more likely to allow yourself to be run by such simulators in the future.
The blockchain can also contain news articles. This does not prevent fake news, but at least it ensures that everyone has a common view of world history, so malicious simulators cannot give one version of world history to some ems and another to others, without putting in the work of creating a fake blockchain.
Woah 😳. Didn’t even think of this use case for a Blockchain.