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Holden Karnofsky

Also known as: Holden

Co-founder of GiveWell and Open Philanthropy; influential figure in effective altruism; author of 'Most Important Century' blog series on transformative AI

Current Role
Member of Technical Staff, Anthropic
Organization
Anthropic
Born
1981
Age ~45

Expert Positions1 topic

TopicViewEstimateConfidenceDate
Will We Get Adequate Warning?Probably65%medium2022

Education

BA in Social Studies, Harvard University

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Overview

Holden Karnofsky was co-CEO of Coefficient Giving (formerly Open Philanthropy), the most influential grantmaker in AI safety and existential risk. Through Coefficient, he directed over $300 million toward AI safety research and governance, fundamentally transforming it from a fringe academic interest into a well-funded field with hundreds of researchers. In 2025, he joined Anthropic.

His strategic thinking has shaped how the effective altruism community prioritizes AI risk through frameworks like the "Most Important Century" thesis. This argues we may live in the century that determines humanity's entire future trajectory due to transformative AI development.

Funding AchievementAmountImpact
Total AI safety grants$300M+Enabled field growth from ~dozens to hundreds of researchers
Anthropic investment$580M+Created major safety-focused AI lab
Field building grants$50M+Established academic programs and research infrastructure

Risk Assessment

Risk CategoryKarnofsky's AssessmentEvidenceTimeline
Transformative AI~15% by 2036, ≈50% by 2060Bio anchors frameworkThis century
Existential importance"Most important century"AI could permanently shape humanity's trajectory2021-2100
TractabilityHigh enough for top priorityOpen Phil's largest focus area allocationCurrent
Funding adequacySeverely underfundedStill seeking to grow field substantiallyOngoing

Links

References

Facts

9
People
Employed ByAnthropic
Role / TitleMember of Technical Staff, Anthropic
General
Websitehttps://www.cold-takes.com
Other
Board MemberRedwood Research
Biographical
EducationBA in Social Studies, Harvard University
Notable ForCo-founder of GiveWell and Open Philanthropy; influential figure in effective altruism; author of 'Most Important Century' blog series on transformative AI
Social Media@HoldenKarnofsky
Wikipediahttps://en.wikipedia.org/wiki/Holden_Karnofsky
Birth Year1981