However, most people wouldn't consider "email" (SMTP) to be a blockchain, even if it's (sorta) decentralized.

But nearly every definition of blockchains does contain an append-only cryptographic log called a "merkle tree". Everything from there gets fairly vague.


This vaugeness leads to the joke: "blockchains are the 'cloud' of merkle trees". This refers to both the similarity to the hype and vagueness around the term "cloud", but with blockchains.

But git is a merkle tree. Is a signed git tree a blockchain? Well, yes and no...

"Blockchain" evolved to describe the space of "bitcoin-like-things". But the exploration space followed in its wake is large, and the evolutionary tree diverges dramatically.

This is similar to how "Roguelike" describes the space of "rogue-like-things", departing dramatically.

Thus you see people on here complaining about how blockchains will burn down the planet because of resource consumption, by which you mean "proof of work", which Bitcoin had.

But many newer "blockchains" use other mechanisms which don't chew planetary resources...

And so there's a disconnect. "I don't like roguelikes because I hate turn based games"... well, is Blazing Beaks a roguelike still?

"Blockchains are bad because they burn down the planet." But what about blockchains with proof-of-stake or a small permissioned quorum?

Since there's no agreement on whether PoW is essential (many might not even know an alternative), two sides arguing about things might actually be arguing about *different things*, thus "shouting past each other", which we do see on here all the time.

I think there's a good "shape" for what we might call a blockchain, but before we get to that, let's get to the other big argument that's happening on here: "blockchains" as an identity space... and a proxy war for other cultural dynamics!

"Blockchain bros": are they real? Yes. Is it everyone in the space? No, but it feels to most outsiders to be enough so that there's good reason for many to be put off.

It's even worse now that NFTs have polluted the space with people ignorant of what they're actually buying.

Side note: NFTs are not copyright, and actually I don't even think copyright (which bottoms out in state violence) is even a good *idea*, but people are being sold something which isn't what they're getting, and it's no wonder that people are mad about it.

That said, broad brush dismissals of this entire space as being white dudebros are *false*, and I have friends who are not dudes and not white who are hurt by broad-brush characterizations.

But on the other hand, don't use my words here to complain about "virtue signaling":

"Virtue signaling" is itself a virtue signal! It's like hipsters being the people who were most worried about hipsters a decade ago.

But "virtue signaling" is a thing everyone does because humans have limited time to assess, so yeah...

Let's get back to architecture again.


ActivityPub is a decentralized protocol, but it is not a blockchain.

However, it's another area in the space. Actually, there's *two different kinds*: "convergent decentralization" and "decentralized cooperating agents"

Almost all the focus of decentralization is in the "decentralized convergence", or sometimes if i'm smug, the "decentralized centralization" space. This is the world of blockchains and "quorums" (we'll come back to that)

Well *that's where the money is*! So... shocker!

However, most of the *important work* that needs to be done doesn't require a ledger, it's in the "decentralized cooperating agents" space. This is the realm of ActivityPub, the "actor model", and distributed capability-secure programming (CapTP!)

(It's also where my focus is.)

"Decentralized cooperating agents" work great with peer to peer systems... objects communicate with each other might cooperate despite being opaque to each other!

Surprised? Consider: you and I can cooperate without me reading your mind!

So: are blockchains essential to decentralization?

No! In fact, decentralized approaches dramatically predate Bitcoin! In fact, blockchains often lead to "reproducing" centralized structures because it's just too easy to "throw the centralized mindset on top of a blockchain"!

BUT! Does this mean that "decentralized convergence" and "decentralized cooperating agents" are at odds??

ALSO NO! I'm about to apply a *different* definition for "blockchain" and then let's think about how they might work together.

What if "blockchain" just meant "a single machine that many people run"?

The idea here is that a blockchain isn't a bunch of decentralized machines... it's a bunch of machines building *one unified abstract machine*. Useful for decentralized agreement on sequential operations.

Except we might actually want to split this up: there are "public" blockchains, like Bitcoin, Etherium, ZCash, and then there are smaller intentionally assembled sets where "here are the five participating machines, if three out of five agree this is the next action, then it is"

It might actually just be better to call the former ones "blockchains" (public-participation convergent machines) and the latter ones "quorums" (private-participation convergent machines).

But those are both "decentralized convergence", but wait a minute, if we're building *one abstracted machine*, can we hook it up as just another machine on something like CapTP?

And oh my god you *CAN* and this is exactly what Cosmos's IBC and Agoric's systems are

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@cwebber this has the potential to get confusing in discussions around stellar's "quorum slices," as they've basically found a quorum based mechanism that works with open membership.

Good thread.

You can have shared ledgers without blockchains, too. The first shared ledgers I knew about were by Todd Boyle:

Could be implemented actually-decentrally by ActivityPub and Spritely.

@bhaugen There were also probably Merkle Trees before Merkle got to claim the name :)

This might be a side trip, but do you think that Merkle Trees are a necessary part of a workable non-blockchain shared ledger?

@bhaugen define "workable", and define "merkle tree" I guess! But this is an interesting question. My first response was going to be to say that merkle trees are necessary, but then I remembered just how much when it comes to ocap-oriented distributed-object abstractions, one can upend one's normal assumptions of how things which are normally built with cryptography can instead be built with object interactions and object references.

@bhaugen It's possible to build one, I've thought of a design. I'm not sure you'd *want to use it* though.

It resembles my suggestion of how multiplayer terminal phase might work in the article that opened this thread.

But I'm not sure it's *useful*, so I'm not sure it's worth elaborating, but I will think about it. Maybe there's a surprising usefulness application.

> how multiplayer terminal phase might work in the article that opened this thread.

This thread has meandered and crisscrossed enuf that "Expand this toot" does not find an opening article...but if I found it, I would read it.

(It has been a fascinating tangle of threads, though....)

@bhaugen I accidentally split it, see the article linked in which is the longform of these threads

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@cwebber While CapTP is the long-term goal, I've been thinking about proposing a system for collectibles using the existing @activitypub protocol (e.g. Offer/Accept/Reject plus collections Add/Remove). Would you be interested in collaborating? The goal is to provide an NFT alternative that avoids financialization but keeps the fun of collecting & ability to trace artist provenance. More like achievements than trading cards

@datatitian @activitypub I'm not interested in building that on AP myself, but I'm interested in doing a writeup in terms of "supporting artists and programmers on the internet" which will include the idea of "digital trading cards" (and attempting to kick the term "NFT" into the trash, and then light the trashcan on fire). If you're interested in providing feedback on that and maybe even helping with it, and maybe we could even include your examples (and i could review them), then great!

@cwebber @activitypub yes, great! What I'd really like your expertise for is validating the usage of ActivityPub and the sequence of Activities. Leave the building up to us implementors 😁 Right.

Ultimately, blockchain is equivalent to the "eternal log file" as on

What Bitcoin adds on top, is defining what contents of each "log message" (which is called a block) mean, verification of those properties, and a decentralized consensus mechanism as well as protocols to collect more than one piece of information into each block.

What Git adds on top, is defining what contents of each "log message" (which s called an object, and can be one of multiple types) mean, merges (a trivial but important addition) and a centralized consensus mechanism (branches, tags, both being just "refs").

@cwebber Proof of Stake is still (always) Five Years Away from proving it doesn’t need to piggyback on PoW and/or doesn’t need always online networks in sit and spin mode (or worse doing PoW just so that it has something to do while it spins).

Personally, I’m at the point of declaring PoS bad for the environment. (If not also “more Ponzi than Ponzi: The Lottery” economically.) And small permissioned quorums we can go back to calling Paxos and rebase-only merkle trees.

@cwebber At this point I *really* want to end the confusion between “blockchain” and “distributed consensus” and my suggestion is we end the confusion by declaring “blockchain” to *only* mean the destroying the planet algorithms that have ~industrial waste~ cryptocurrency by -products and go back to older names for everything else. Because it’s a LOT easier to shutdown PR nonsense if we can just say “Technically, yes all blockchains are wasteful” and move on with our technical lives.

@cwebber But that’s my minority take here. A lot of VC money is getting thrown at the confusion and people are profiting off it. We can solve it technically, easy enough and stop letting PR spin confuse everyone about which distributed databases are to toxic or not.

@cwebber Proof of stake is almost as bad as proof of work, as it leads to dramatically increased e-waste and/or hardware shortages.

Plus, both systems amount to Proof of Wealth, meaning they end up being another way to accelerate the movement of power and money to the rich, as the rich insert themselves as middlemen and soak up the extravagant transaction fees.

@mathew What structurally leads to dramatically increased e-waste? I agree that structurally it means "proof of plutocracy" but don't understand the other argument... PoS as I understand it encodes who the voting members are based on who holds wealth on the chain, which leads to plutocratic problems but I'm not aware of the resource problems it has (other than more people needing to carry around a long log of history than maybe necessary)

@mathew I'm a big critic of PoS's plutocratic nature, I just like to be a critic along the architectural problems systme have, so please don't misread.

@cwebber Miners buy high end GPUs and thrash the hell out of them, or buy ASICs which are no use for anything else. Either way, they end up as e-waste after about 18 months when they are no longer competitive. A study suggests that each Bitcoin transaction makes about as much e-waste as binning an iPhone.

@cwebber And for the proof-of-stake variants, it's big SSDs which are thrashed and then discarded.

@mathew proof of stake doesn't have mining, so you're referring to proof of work?

@mathew well the term "mining" is used but it doesn't apply the same way as resource mining as you described

the criticisms you're raising are true and accurate for proof of work, though.

@mathew that criticism of proof of space is accurate imo, I'm just advocating for giving the right criticisms for the right things

@cwebber Are there any low-resource-use Proof of Stake systems in use? I remember Iota seeming superficially promising, but I haven't seen it actually used anywhere, and it looks like it's only just going through some sort of complicated staking mechanism.

@mathew I think Cosmos's Proof of Stake (and things built on top of it, like Agoric's blockchain) fits that definition, but I don't know much of the details

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