It is well known that increasing the 1MB Bitcoin block limit decreases block propagation speed. As someone who follows the scaling debate I have often noticed that people tend to ignore (or mention only in passing) that bigger blocks directly decrease the security of Bitcoin, and tend to stress other factors first (e.g. that bigger blocks give big miners an edge).

Why do bigger blocks directly harm security? because the analysis of Bitcoin security as carried out in the original Nakamoto paper implicitly assumes instant block propagation. When propagation is no longer instant, more temporary forks occur => some percent of the hashing power is wasted because it was invested in orphans and not in the longest chain. Thus, an attacker attempting a 51% attack has to compete agains less than 100% of the hashing power.

Satoshi had a good hunch to set all the parameters of Bitcoin to something that works. All of them are arbitrary (21 million coins, 10 minute average block confirmation, 2016 block difficulty adjustment, etc) but they needed to work well in conjunction to make the thing fly (and the “thing” here is way more than the software, it’s also all the cascading layers of game theoretic incentives and meta incentives that make Bitcoin tick).

Taking one of those parameters and arbitrarily changing it in a direction that naively “scales” but clearly works against Bitcoin’s basic security premise, is naive and harmful (or in short, political).

Here is a fun analogy. Think of the Wright Brothers airplane. It wasn’t perfect, but it got all the parameters (shape, weight, ratio between the wingspan and body, etc) into the range where the thing could take off.

While it is true that increasing the wingspan does create more lift in a first approximation, it was not the way to “make airplanes scale”. The complex beasts that are modern airplanes developed through a myriad of subtle, engineering driven, well tested optimizations to the aerodynamics of wings, material science etc.

The analogy to Bitcoin should be clear. Insisting on increasing the 1MB block size parameter will not lead to meaningful success any more than increasing the wingspan of airplanes did.

The only sensible way forward is to have engineering driven optimziations pave the way by fixing bugs (e.g. malleability), creating a more robust protocol that is less amenable to miner centralization (and the toxic politics that inevitably follow) and laying down the foundations necessary for the network’s success, most likely by scaling in other layers.

If we want Bitcoin to go to the moon (and I totally think everyone does), we need to insist on the ladder being well grounded.