It was a good discussion, and I really enjoyed the capability to actually discuss about solutions with you instead of the usual "meh crypto scam". Still we are getting a bit too deep for regular HN comments, and I somehow feel like there's just the two of us here. So that will be my last answer, but I'm glad to have a call with you for easier and more in depth discussion if you would like that.

> It's hard to sell a painting without having possession of it, and I'd imagine, independent authentication in these high value markets

See that's actually not the target for NFTs as I see it.

Most people see the art world as very fancy paintings worth 6 figures. But I'm talking about the more down to earth kind of art. The kind that your average art-enthusiast buys at Art Basel, photographs or lithographies in the 100$ to 5000$ range. The bread and butter of the "art" scene.

There are no experts to certify these pieces, only for ultra high ends can you find such specialists.

Also these pieces are not worth enough to justify such certifications.

Still, it's very important for enthusiasts to own the pieces, it's part of why people buy them from the artist instead of just getting it printed. To an art enthusiast, it doesn't matter if 20000 people have that same art printed on a poster at home, or as wallpaper on their laptop. It matters to them that they have it, they bought it from the artist, and they have some physical or digital token to _feel_ their ownership.

> Which is absolutely worthless unless you know the signature of the artist. If you already know this, then you don't need the NFT.

I don't understand your point here. A typical certificate of ownership is just a paper with a sentence such as "I, Mr. X, hereby sell my photograph Y to Mr. Z". This paper is then signed by the artist, a notary, and the new owner.

An NFT contains exactly the same information, except the text is replaced by a Json containing a thumbnail of the art for reference, and signatures are digital. The fact that these tokens of ownership are on the blockchain allows you to verify them yourself, instead of going through calling the notary. And you can transfer these ownership (which ultimately link to the public key of the artist who created it) directly with a seller.

It's more auditable, cheaper for both artist and buyer, and overall simpler and faster than paper proofs of ownership.

> I see and understand problem is how does Blockchain solve any of this?

Let's get back to the example and consider that there are just 2 layers in this settlement: back office and front office.

The back office is the slow, golden record, of who owns what share. The back office is always correct, they will never allow credit or delay. If you bought a share but did not receive it yet, the back office will just consider that you don't have it, you cannot sell it.

Yet, you really want to be able to buy and sell a share in the same day. So you create a cache on top of the back office, called the front office. Technically it's quite similar to having a memcached or redis between an HTTP server and the filesystem.

This cache allows you to be faster, but the side effect is that there are now potential I coherency between what you have for real (data on the filesystem, or shares in your possession), and what you think you have (cached data in redis, or virtual ownership of shares in your front office system).

Note that the back office, or filesystem, is _never wrong_ here. The matching issues never happens at the bottom layer, only at the layers on top of it.

You memcached can be out of sync with your files if you changed them, but not the other way around.

Blockchains are like having a back office system that is fast enough to not require you to have a front office. It's like having SSDs that are as performant as your memcached. You just don't need these layers of cache anymore, and by removing them, you avoid the whole class of consistency, matching and settlement issues than happen with cache coherence.

So now let's discuss about why back office is that slow to begin with, and thus why blockchains cannot be replaced by just "having better APIs for a faster back office".

What makes back office slow is that there are always 2 parties in a trade, and none of these parties can ultimately trust the other.

You can never be sure that the party you're agreeing with to buy a share really has that share. Since back office needs to be perfect, by definition, it will have to wait until the shares are actually delivered for real to consider the trade done.

No amount of database or API can fix that _unless_ both parties of the trade share the same database of what they have and owe each other.

Such shared, centralized databases exist, at small scale, but they don't expand between more than a couple of banks or institutions.

Ultimately businesses cannot blindly trust each other, it's just not an acceptable counterparty risk when big money is at stake.

Blockchains are shared databases that allow the storage of transactions between entities that don't have to trust each other's records. As such, they are perfect settlement systems, and are fast enough to not require additional layers of caches and coherence issues.

> Because they are incredibly expensive, and probably don't solve the problem you want to solve.

You have to realize the massive scale of what back and middle office is for the financial industry. I'm not joking when I say easily half of the resources of any bank, investment company or broker are dedicated to just that.