As far as NFTs are concerned, the existence of multiple incompatible blockchains is indistinguishable from what would be considered a network partition within a single blockchain for cryptocurrency.
@stagas:
> Can't they have a public personal ledger somewhere for people to audit?
Then you need to coordinate on a common authority to rely upon for the timestamping. Blockchain's whole purpose is to eliminate this dependency.
As it stands this isn't very valuable yet but in my mind an important milestone.
Without third-party timestamping or blockchain, the same token can be sold to multiple buyers, and nothing can be used to determine which buyer is the first ("real") buyer.
This is the whole reason blockchain was invented. It wasn't possible to do it at all before that.
Blockchains simply reduce the power and trust required in the third party by offering a different set of tradeoffs.
I haven't puzzled it though but intuitively it feels like you wouldn't be able to achieve the "same validity" (aka you'd have a weaker set of guarentees) without the liveness of a blockchain like system. Whether you agree with what threshold of validity is acceptable is a different matter.
An identity + timestamping mechanism would guarantee uniqueness of ownership, and a blockchain performs this in a relatively decentralised and trustless manner.
If the restrictions of never involving third parties (in proofs of ownership or otherwise) is acceptable, then there's no need for any schema bar making the transaction itself.
The issue with removing the third party entirely (as the auther suggests) is the verifiability of the timestamp to any interested third parties. The simplest scenario is proof of existence of the artwork at time T. Without a timestamping mechanism there's nothing stopping the creator lying about when it was created, or when this transaction took place.