Will whole brain emulation matter for the AI transition?

Summary WBE is decades away assuming no AGI. Expert timelines for human brain emulation are mid-2040s at the earliest, with wide error bars, and generally are for "simulating the brain for a few seconds" rather than for any useful length of time. There is essentially no overlap with AGI timelines.WBE could be achieved several years after AGI, but probably not several months after. It takes months to physically prepare, slice, and scan a human brain; doing tests on mice will take months; and collecting functionalization data will take months unless simulations can substitute for most physical experiments.Emulations are expensive for what they do. Each one requires 10,000–40,000 H100-equivalents and costs $20K–$80K/hour, running at up to ~5× real-time. Emulations would be tens to hundreds of times more expensive per unit of cognition than humans, and orders of magnitude more expensive than AI systems. Emulations — including distilled emulations — are unlikely to ever be competitive with purpose-built AI for cognitive work.The safety case is weak. Emulations aren't obviously more trustworthy than AI, aren't a competitive starting point for building superintelligence, and it's not clear they tell you much about human values that you can't learn more cheaply from humans and LLMs.Pre-AGI investment is probably not cost-effective. A very simple BOTEC produces an estimate of 0.3 bp/bn[1]for a $100M investment. The value is concentrated in a narrow scenario: emulations somehow enable large x-risk reductions and a global AI moratorium is in place to allow emulation technology to reach maturity, both of which seem unlikely.IntroductionWhole brain emulation (WBE) sometimes comes up as a potential tool in AI safety strategy — either as an alternative path to transformative AI with better alignment properties, or as a way to scale trusted human cognition during a critical period. This memo tries to assess whether either hope is realistic by asking two questions:When could we get W