Garzik, Andresen Warn that Maxwell Bitcoin Roadmap Ignores Hard Questions on Block Size & Higher Fees

Two key Bitcoin Core committers, Jeff Garzik and Gavin Andresen, have together responded to the bitcoin scalability roadmap written by fellow committer Gregory Maxwell with some dire forecasts.

There are of course many other contributors to bitcoin development, but the Bitcoin Core committers, Garzik, Andresen, Maxwell, Pieter Wiuelle and Wladimir J. van der Laan, have write access to the bitcoin repository and are ironically a central planning group on bitcoin network improvement.

Garzik and Andresen, both authors of different formal Bitcoin Improvement Proposals (BIP) to increase bitcoin’s block size, note that, while the Maxwell roadmap has some good points, it does not speak to all bitcoin users and permits bitcoin to shift to a new economic policy of higher fees.

With the doubling in transaction volume over the past year, remaining at the current block size of 1MB will result in higher fees and solidifies subjective human decision making over bitcoin’s economic model, according to Garzik and Andresen.

As the two leading bitcoin developers demonstrate, the higher fees will impact all bitcoin users, yet this is only mentioned by Maxwell in paragraph 18 of the proposal:

These proposals help […] prevent defection between the miners from undermining the fee market behavior that will eventually fund security.

Garzik and Andresen also highlight the failure of the Scaling Bitcoin workshop to catalyze decisions making on block size:

One of the explicit goals of the Scaling Bitcoin workshops was to funnel the chaotic core block size debate into an orderly decision making process. That did not occur. In hindsight, Scaling Bitcoin stalled a block size decision while transaction fee price and block space pressure continue to increase.

They believe that the workshops surveyed consensus on core block size, with 2MB being widely supported, but there was no decision made by the Bitcoin Core group.

Garzik and Andresen indicate that many users of the bitcoin ecosystem have concerns that the Maxwell roadmap is an effort to shift bitcoin away from a network of peer-to-peer cash payments to a settlement system of side chains or payment channels, where many parties who invested in it are pushed out. This is complicated by the fact that the biggest side chains venture Blockstream employs Maxwell, Wiuelle, and Adam Back, inventor of the hashcash proof-of-work and decentralized mining used in bitcoin.

Garzik and Andresen also cite language articulated in the RootStock white paper.

If Bitcoin block size is not increased via a hard-fork, when the next Bitcoin reward halves, Bitcoin transaction fees may become prohibitively high for certain applications.

They re-emphasize that stalling on the hard issues of block size and higher fees will produce significant market changes in the short term.

…in the short term, we have a disappointing situation where a subset of dev consensus is disconnected from the oft-mentioned desire to increase block size on the part of users, businesses, exchanges and miners. This reshapes bitcoin in ways full of philosophical and economic conflicts of interest. As noted here, inaction changes bitcoin, sets it on a new path.

Garzik and Andresen are not opposed to the Maxwell-led “segregated witness” proposal. They recommend processing it in parallel to a core block size resolution that will mitigate high fees and contain software-driven limitations on block size rather than relying on corruptible or subjective human decision making.

Various bitcoin ecosystem luminaries and technologists tweet their agreement with Garzik and Andresen.

Garzik and Andresen conclude:

A better way forward includes leadership on a definitive short term core block size decision, plain talk with users about exploring new fee market economic theories and system survival theories, and plain talk with users about the risks and possible negative consequences of getting stuck at 1M.

garzik&andresen joint state