Historical Hard Forks

if (block.GetSerializeSize() > MAX_BLOCK_SIZE)
    return error("CheckBlock(): size limits failed");

Remark 27.1 (The Scaling Trilemma Applied)

The block size debate is a manifestation of the scaling trilemma:

• Throughput: Larger blocks → more transactions per second
• Decentralization: Larger blocks → higher node costs → fewer nodes
• Security: Fewer nodes → increased centralization risk

The debate centered on where to position this tradeoff.

Remark 27.2 (XT Failure Analysis)

Bitcoin XT failed due to:

1. Insufficient miner signaling: Never approached 75% threshold
2. Community opposition: Perceived as hostile takeover
3. Technical concerns: Exponential growth criticized as reckless
4. DDoS attacks: XT nodes were targeted; the attackers were never identified

Peak XT node share: ~12% (late 2015), then rapid decline.

Remark 27.3 (Emergent Consensus Critique)

Critics of "Emergent Consensus" identified a game-theoretic objection: without a Schelling point (hard limit), miners have incentive to produce maximum-size blocks to:

1. Collect more fees (more transactions)
2. Disadvantage smaller competitors (propagation delay)

This could lead to unbounded growth and centralization.

if (MTP(tip) − MTP(tip − 6) > 12 hours):
    difficulty = difficulty × 0.8

Remark 27.4 (EDA Instability)

The EDA created oscillating dynamics:

1. Low BCH price → miners leave → slow blocks → EDA triggers
2. Difficulty drops → BCH more profitable than BTC
3. Miners switch to BCH → fast blocks → difficulty rises
4. BCH less profitable → miners return to BTC → cycle repeats

Result: more than 100,000 "extra" BCH mined ahead of schedule by the time the EDA was retired (November 2017).

Remark 27.5 (The Hash War)

The BCH/BSV split involved an unusual "hash war" in which both sides threatened to attack each other's chain:

• Both chains mined at a loss to accumulate work
• BSV side threatened 51% attacks
• Exchanges suspended trading during uncertainty
• Eventually, both chains coexisted with replay protection

Remark 27.6 (BSV Controversies)

BSV faced unique challenges:

• Association with Craig Wright's disputed Satoshi claims
• Legal threats against critics
• Delisting from Binance, Kraken, ShapeShift
• Multiple 51% attacks (2021)
• Centralization concerns (few large miners)

Remark 27.7 (Limits of ASIC Resistance)

Changing the proof-of-work algorithm to be "ASIC-resistant" provides only temporary protection:

1. No fixed algorithm is known to resist ASIC implementation indefinitely
2. GPU-mineable algorithms have historically attracted botnet hash power (stolen compute)
3. Algorithm changes cause disruptive hard forks
4. Smaller hash rate increases 51% attack vulnerability

Remark 27.8 (Bitcoin Diamond Reception)

Contemporary press coverage characterized Bitcoin Diamond as a "fork for profit"; development activity declined to minimal levels within a few years of launch.

Remark 27.9 (The Long Tail of Forks)

Dozens of Bitcoin forks have been created. Most share characteristics:

• Minimal development post-fork
• Value decay relative to BTC
• Low liquidity and exchange support
• Security vulnerabilities from small hash rate

The "free coins" distribution model proved insufficient for building sustainable networks.

Remark 27.10 (SegWit2x Failure Factors)

SegWit2x failed despite ~90% miner signaling because:

1. No replay protection: Intentionally omitted, seen as aggressive
2. Core developer opposition: None of Bitcoin Core signed NYA
3. User opposition: Futures markets showed BTC premium over B2X
4. Business defections: Key signatories withdrew support

Remark 27.11 (Lessons from SegWit2x)

The episode is widely read as showing:

• Miner signaling is necessary but not sufficient
• Users (economic nodes) have effective veto power
• Futures prices provided one public signal of relative valuation (though the B2X futures market was thin)
• Hard forks require broader social consensus than soft forks

Its failure strengthened the "User Activated" model of consensus.

Remark 27.12 (Fork Value Decay)

Empirically, Bitcoin forks exhibit value decay relative to BTC following a pattern consistent with:

V_fork(t) / V_BTC(t) ∝ e^(−λt)

where λ varies by fork; the endpoint ratios imply average decay rates of approximately λ ≈ 0.4/year for BCH and λ ≈ 0.7/year for BTG.

This suggests that network effects compound over time, increasingly favoring the dominant chain.

Remark 27.13 (Fork Success Factors)

Analysis of historical forks suggests success factors:

1. Clear value proposition: Must offer something BTC cannot
2. Technical competence: Must maintain security and development
3. Community: Must build independent user base
4. Timing: Early forks captured more value
5. Replay protection: Essential for user safety

Remark 27.14 (Why Hard Forks Rarely Succeed)

The historical record suggests hard forks face structural disadvantages:

• Network effects strongly favor incumbents
• Developer talent tends toward dominant chain
• Liquidity fragmentation harms both chains initially
• User confusion degrades trust
• Minority chain faces security challenges

Soft forks, by maintaining compatibility, avoid these problems.

Remark 27.15 (The Fork Right)

Despite their typically poor outcomes, the ability to fork remains important:

• Provides exit option, limiting majoritarian abuse
• Creates natural experiment for different approaches
• Demonstrates that Bitcoin is not controlled by any group
• Historical forks strengthened BTC's Schelling point

The ability to fork, though rarely exercised successfully, serves a structural function: it bounds what any majority can impose.