What are we trying to achieve? It’s very simple actually — all we’re trying to do is maintain a simple table of balances on a piece of paper. This table will show how many coins each of our heroes has. The trick is, because we can’t have one piece of paper that holds the only source of truth — we’re going to have to keep things equal and let each of the gang maintain their own version — this is the decentralized part. And naturally, we’re also going to hope that all 4 pieces of paper eventually show the same thing — this is the consensus part.
Nothing in the statement of the problem requires a block chain.
Maintaining distributed ledgers is not a difficult problem except for one niggling detail: double spending. In other words, if the scenario you're looking at has no risk of double spending, a block chain isn't going to help you at all.
To expand on the article's example...
Jack is down to his last coin and gets a brilliant idea. He'll pay Kate and Hugo each one coin during the day. If he succeeds, Jack can forge one coin out of thin air.
The islanders face a dilemma. Which of Jack's two payments should be accepted? Accepting the payment to Kate means that Hugo loses his. Accepting the payment to Hugo means that Kate loses hers.
Accepting both payments is a non-starter. The islanders may as well just start bartering again if monetary scarcity can't be preserved.
This is the motivating example behind block chains. The system we know as Bitcoin had been largely worked out by the time Satoshi released the white paper in 2008. Digital signatures and hash chains mean that forgery of coins or payments is practically impossible.
What was missing was a way to make double spending difficult, without invoking a central authority.
Excellent reply. One could expect HN to be less susceptible to this fad that is blockchain.
To be fair, the author never said it was the only or best solution, but articles similar to this could make use of a note mentioning that there is no need for blockchain and there are more efficient ways to do this.
The consensus here is trivial to control by the strongest of the group. What if when Hugo sent the 200 coins, he said “oh we’re allowed to generate 200 coins if it has been over 3 days of no coin generation” and his statement would be impossible to verify because:
1- They have no way to get in touch with the central authority, the developer (author of the blog post), who can tell the users if the new consensus rule is allowed or not.
2- They have no written account of the consensus rules, which would help to at least invalidate new consensus rules that seem to conflict with the written ones.
So what would happen if Hugo did this? Well if he’s the strongest of the bunch, he could simply impose on the group and say “this is a new consensus rule, accept it or else”. So much for decentralized consensus!
> Well if he’s the strongest of the bunch, he could simply impose on the group and say “this is a new consensus rule, accept it or else”. So much for decentralized consensus!
Isn't this always the case? If Hugo is strong enough, he can also bully his way into abandoning the blockhain, and relying on his word for what everyone's balance is.
(Of course, this kills any notion of an actual economy, and becomes a totalitarian regime powered by effectively slave labor...)
> Is this an ideal blockchain implementation? Probably not. It can be improved in many ways.
To your point, though, couldn't the rules just be part of the block chain and documented as a "transaction"? Any change in the rules would just be another transaction and require majority approval.
Inefficient, mostly not new either because in the past you'd have one person with that responsibility: the one who has experience with ledger. Now everyone's a notary. How it'd happen with centralized/specialization is another person would cut wood, yet another would hunt fish, and everyone would do their part (you can see this in effect in the movie The Beach [1] though the group is larger than 4 like in this example; also in Cast Away its just that there's only 1 person there who has to do everything by himself which makes it a redundant example). Everyone specializes in something because that is more efficient when HR are scarce. Because the group is small its easy to keep track who's doing what; instead of pet peeves like ledger.
So in short either you're so bored that you don't have anything better to do, or you're busy with surviving. If you're bored and you happen to have pen and paper I can recommend something different: PnP RPG. Such relies on something you'll always have with you even when you're alone (see Cast Away [2] as well): your imagination.
For anyone interested, there is literally no evidence that any society anywhere, ever, switched to using money because using barter was so onerous. [0] On an island like this one the inhabitants would inevitably create a system based on mutual aid and ongoing negotiation of responsibilities to one another. While this is a fun article, to me it exposes how cryptocurrencies are primarily useful as a value store and a means of speculation rather than a solution to actual human-scale problems.
If there are four of you on a tiny island and you're not running an informally communist society, something's wrong.
Possibly what's wrong is that one of you is a libertarian.
I'm no purely being flippant here - four people are going to be so inter-reliant and form such a small, tigh-knit group, that keeping track of balances and debts is likely to cause more problems than it could possibly solve.
I agree. You're more like a family at that point than four LLCs.
Then again, I wonder how many people reading that blog post and nodding along are already sketching out a brilliant idea to bring this back home, and have their spouse and kids get on the handwritten blockchain wagon.
[+] [-] apo|7 years ago|reply
Nothing in the statement of the problem requires a block chain.
Maintaining distributed ledgers is not a difficult problem except for one niggling detail: double spending. In other words, if the scenario you're looking at has no risk of double spending, a block chain isn't going to help you at all.
To expand on the article's example...
Jack is down to his last coin and gets a brilliant idea. He'll pay Kate and Hugo each one coin during the day. If he succeeds, Jack can forge one coin out of thin air.
The islanders face a dilemma. Which of Jack's two payments should be accepted? Accepting the payment to Kate means that Hugo loses his. Accepting the payment to Hugo means that Kate loses hers.
Accepting both payments is a non-starter. The islanders may as well just start bartering again if monetary scarcity can't be preserved.
This is the motivating example behind block chains. The system we know as Bitcoin had been largely worked out by the time Satoshi released the white paper in 2008. Digital signatures and hash chains mean that forgery of coins or payments is practically impossible.
What was missing was a way to make double spending difficult, without invoking a central authority.
[+] [-] nbeleski|7 years ago|reply
To be fair, the author never said it was the only or best solution, but articles similar to this could make use of a note mentioning that there is no need for blockchain and there are more efficient ways to do this.
[+] [-] hudon|7 years ago|reply
1- They have no way to get in touch with the central authority, the developer (author of the blog post), who can tell the users if the new consensus rule is allowed or not.
2- They have no written account of the consensus rules, which would help to at least invalidate new consensus rules that seem to conflict with the written ones.
So what would happen if Hugo did this? Well if he’s the strongest of the bunch, he could simply impose on the group and say “this is a new consensus rule, accept it or else”. So much for decentralized consensus!
[+] [-] pavel_lishin|7 years ago|reply
Isn't this always the case? If Hugo is strong enough, he can also bully his way into abandoning the blockhain, and relying on his word for what everyone's balance is.
(Of course, this kills any notion of an actual economy, and becomes a totalitarian regime powered by effectively slave labor...)
[+] [-] joekrill|7 years ago|reply
> Is this an ideal blockchain implementation? Probably not. It can be improved in many ways.
To your point, though, couldn't the rules just be part of the block chain and documented as a "transaction"? Any change in the rules would just be another transaction and require majority approval.
[+] [-] Lapsa|7 years ago|reply
[+] [-] pickpuck|7 years ago|reply
[+] [-] Fnoord|7 years ago|reply
So in short either you're so bored that you don't have anything better to do, or you're busy with surviving. If you're bored and you happen to have pen and paper I can recommend something different: PnP RPG. Such relies on something you'll always have with you even when you're alone (see Cast Away [2] as well): your imagination.
[1] https://www.imdb.com/title/tt0163978/
[2] https://www.imdb.com/title/tt0162222/
[+] [-] teachrdan|7 years ago|reply
[0] From "Debt: The First 5000 Years," by David Graeber https://www.mhpbooks.com/books/debt/
[+] [-] unknown|7 years ago|reply
[deleted]
[+] [-] geraldbauer|7 years ago|reply
[1] https://github.com/bitsblocks/islandcoin-whitepaper
[+] [-] JohnnyConatus|7 years ago|reply
[+] [-] Nursie|7 years ago|reply
Possibly what's wrong is that one of you is a libertarian.
I'm no purely being flippant here - four people are going to be so inter-reliant and form such a small, tigh-knit group, that keeping track of balances and debts is likely to cause more problems than it could possibly solve.
This is a situation for trust, not currency.
[+] [-] pavel_lishin|7 years ago|reply
Then again, I wonder how many people reading that blog post and nodding along are already sketching out a brilliant idea to bring this back home, and have their spouse and kids get on the handwritten blockchain wagon.
[+] [-] etherael|7 years ago|reply
[+] [-] ada1981|7 years ago|reply
I’m inspired for us to implement something based on this as a class.
The island is here > http://Majagual.org
Would love to find other cool ideas for projects and inspiration.
[+] [-] 2RTZZSro|7 years ago|reply
[+] [-] OptiKey_Julius|7 years ago|reply
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