The Debate about Block Size of Bitcoin is Back Again

The Debate about Block Size of Bitcoin is Back Again

First heating up in 2015, a debate about how best to scale the digital currency’s underlying blockchain remains the dominating disagreement. Despite the best efforts of developers to bring what they say is more nuance to the discussion, a single metric remains the biggest sticking point.

For the next year, some miners are again calling for measures that would raise the bitcoin block size in an effort to support more transactions and grow its user base. The developers behind Bitcoin Core remain focused on increasing capacity by way of top-level protocols, arguing that developers and academics believe this is the safest way forward for the still-experimental project.


For one, a viable scaling solution that boosts the block size, but doesn’t focus on the metric, Segregated Witness, has completed testing and has been released. Further, a new mining pool and a prominent bitcoin investor, Roger Ver, are currently running software that supports larger blocks.

The presence of a major miner means the big block movement has some advantage this time in threatening to block Segregated Witness, or perhaps creating its own network through a process known as a hard fork.

Chairperson of the board at the Factom Foundation, David A Johnston, argued that given these recent events a fork is inevitable. In a series of blog posts, he put forth the idea that both groups now have different goals, and that because of this, they may be better off working on two separate networks.

David A Johnston said:

“After two-plus years of debate, it seems the few months of time a fork would cost is a small price to pay in order to get development back on track regardless of which side you agree with.”

block size

Coinkite CEO and founder Rodolfo Novak said:

“I don’t think it’s going to happen. There is a very-loud-micro-tiny-minority making arguments not based on reality or future resiliency.”

Novak noted that Bitcoin Unlimited follows similar proposals, including Bitcoin XT and Bitcoin Classic, both of which released code to increase the block size to 8 MB and 2 MB up from 1 MB today. Nevertheless, while these proposals generated discussion at first, neither succeeded at reaching the 75% hash rate support threshold to trigger an upgrade. The continued support of miners has some observers taking this fork attempt seriously.

Steven McKie, the product operations manager at Yours, said:

“If the hash rate continues to climb, and I see no reason why it won’t, it is a real concern.”

However, it’s hard to say with other scaling solutions on the way. McKie pointed to the fact that recent announcements suggest Segregated Witness and Lightning are moving forward.

He noted:

“With Lightning-like implementations coming online, it may dull the block size debate enough to keep things going business as usual. It’s hard to gauge at the moment until we see next moves.”

However, Johnston thinks that the only natural solution to the long-standing debate is for the network to split along social lines.

He mentioned:

“Rather than continue endless fights on the topic, it seems more productive for the two groups to go their separate ways.”


He argued that split of ethereum was a great example of a successful social fork, since each group can now focus on their respective vision for the network without the previous bitterness. On the other hand, BTCC chief operating officer Samson Mow argued that ViaBTC and others could fork to form their own currency at any time.

He said:

“If they truly believe the current block size is holding back exponential adoption, causing users to suffer from high fees or unreliable confirmation times and preventing business with millions of users from integrating bitcoin, then shouldn’t they fork to solve all of those dire problems?”

However, it seems the two groups are still attached to their economic marriage. Mow worried the move could threaten not only bitcoin’s future but also the livelihood of those who are dedicated to supporting it. Still, these comments suggest that the past ethereum hard fork continues to be a reference point in bitcoin’s debate. The best-known display of a hard fork without full support, the two networks now both operate separately, commanding about as much value as they did before.

Nevertheless, bitcoin’s supporters believe its status could be harmed by a similar move, eroding confidence that the network will deliver on its promise to differ from traditional, top-down payment networks by ditching majority rule. In this way, the hard fork debate may be more about whether 95% is too high a threshold to enact a change on a blockchain, or whether all participants in a blockchain are really part of a willing economic coalition.

Johnston worried that bitcoin will never progress if changes to the software require all of its participants to agree. Moreover, he said that the 95% level of adoption seemed a recipe for calcification, where innovations effectively became impossible to be adopted. Others, like faculty member at the University of Nicosia, George Papageorgiou, are optimistic about future of bitcoin and see the block size debate as a healthy ongoing conversation.

He said:

“Discourse and different opinions are very much a part of this evolution and I don’t think they should stop or be hampered in any way.”


While many bitcoin developers and observers oppose the most recent effort to fork, most agree that the option is on the table. Adding fuel to the fire is that, without solid definitions, everyone is free to come to their own conclusion about how and when such decisions are made.

Mow mentioned:

“There’s nothing wrong with a hard fork. The only question is how it’s done.”

This disagreement has also arguably diminished developer attention to the issue. Blockstream co-founder and Bitcoin Core developer Matt Corallo noted the lack of hard fork proposals at bitcoin’s most recent annual developer conference, noting that Core developers are not ignoring the topic.


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