The Case Against Formal Verification, 50 Years Later
ivan-gavran.github.io
August 16, 2026
8 min read
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49/100
Summary
Interest in software verification has surged, with a notable increase in Google Trends searches for formal verification and formal methods over the past two years. Many engineers are now learning Lean and exploring new specification languages, indicating a growing excitement around the topic.
Key Takeaways
- There has been a significant increase in interest in formal verification and methods, as evidenced by a spike in Google Trends searches over the last two years.
- AI coding has created a demand for software correctness assurance due to the lack of understanding of AI-generated programs.
- The 1979 paper "Social Processes and Proofs of Theorems and Programs" argues that program verification is unlikely to affect confidence in programs, a claim that is being re-examined in light of recent developments.
- Modern specification languages, like Quint, facilitate the verification of specifications against informal requirements, addressing concerns about the translation process from informal to formal specifications.
Community Sentiment
Positives
- Lean's powerful type system allows for making invalid states unrepresentable, a feature that stands out in the formal verification landscape.
- Building a formally verified workflow engine in Lean was surprisingly easy for one user, highlighting its potential for creating reliable systems.
- Empirical evidence from CompCert shows that formal verification can lead to high confidence in compiler correctness, outperforming traditional testing methods.
Concerns
- Many commenters doubt the reliability of formal verification, questioning whether the specifications are inherently more correct than the implementations they verify.
- The model-code gap remains a significant hurdle, with users struggling to find straightforward methods to bridge the gap between formal models and actual code.
- Concerns linger that increased computational power doesn't necessarily favor formal verification over extensive testing, leaving some skeptical about its practical advantages.
