Subject: Re: [bitcoin-dev] Fwd: Block size following technological growth

From: Pieter Wuille <[email-masked]>
Date: Fri, 7 Aug 2015 20:10:48 +0200

On Aug 7, 2015 7:50 PM, "Gavin Andresen" <[email-masked]> wrote:
>
>
> On Fri, Aug 7, 2015 at 12:30 PM, Pieter Wuille via bitcoin-dev <
[email-masked]> wrote:
>>
>> If the incentives for running a node don't weight up against the
cost/difficulty using a full node yourself for a majority of people in the
ecosystem, I would argue that there is a problem. As Bitcoin's fundamental
improvement over other systems is the lack of need for trust, I believe
that with increased adoption should also come an increased (in absolute
terms) incentive for people to use a full node. I'm seeing the opposite
trend, and that is worrying IMHO.
>
>
> Are you saying that unless the majority of people in the ecosystem decide
to trust nothing but the genesis block hash (decide to run a full node)
there is a problem?

I shouldn't have said majority, sorry. But I do believe that as the odds at
stake in the system go up, so should those who take an interest in
verifying. That doesn't seem to be the case, and is a problem, where that
is a result of the block chain size or not.

> If so, then we do have a fundamental difference of opinion, but I've
misunderstood how you think about trust/centralization/convenience
tradeoffs in the past.
>
> I believe people in the Bitcoin ecosystem will choose different
tradeoffs, and I believe that is OK-- people should be free to make those
tradeoffs.

I agree. Though I believe that the blockchain itself cannot offer many
tradeoffs, and by trying to make it scale we hurt the whole system. The
place to introduce tradeoffs is in layers on top - there you can build
systems with various levels of trust without hurting others.

> And given that the majority of people in the ecosystem were deciding that
using a centralized service or an SPV-level-security wallet was better even
two or three years ago when blocks were tiny (I'd have to go back and dig
up number-of-full-nodes and number-of-active-wallets at the big web-wallet
providers, but I bet there were an order of magnitude more people using
centralized services than running full nodes even back then).

That's inevitable, I'm sure.

> I firmly believe that block size has very little to do with the decision
to run a full node or not.

Within certain limits, maybe not. Within certain limits, maybe it also does
not incentivize trusted miner setups like SPV mining (which hurt the
security of SPV nodes tremendously).

But if the reason for increasing is because you fear a change of economics,
then it means you prefer not dealing with that change. I believe you prefer
not dealing with it ever, and would rather have a system where as much as
possible happens on-chain, even when we unknowingly go beyond those limits.
I think we don't do the ecosystem a service by promising that such a future
is possible without compromises.

So, I think the block size should follow technological evolution, and not
reenforce the belief that the block size should follow demand. There will
always be demand, and we should learn to deal with it.

-- 
Pieter