Researchers including David Wolpert and Carlo Rovelli have analyzed the Boltzmann brain hypothesis, questioning the reliability of human memories. Their work highlights circular reasoning in arguments about entropy, time, and memory. The study appears in the journal Entropy.
SFI Professor David Wolpert, SFI Fractal Faculty member Carlo Rovelli, and physicist Jordan Scharnhorst examined the Boltzmann brain hypothesis in a recent paper. This idea posits that memories and perceptions might arise from random entropy fluctuations rather than a real historical sequence. Such fluctuations could create the illusion of a coherent past without any actual events preceding it. The researchers built a formal framework to assess how assumptions about time influence conclusions on entropy and memory reliability. Materials provided by the Santa Fe Institute describe their approach as connecting the hypothesis to the second law of thermodynamics and the past hypothesis, which assumes a low-entropy Big Bang origin. A core tension stems from Boltzmann's H theorem, which is time-symmetric despite explaining entropy's apparent one-way increase. The authors introduce the 'entropy conjecture' to expose circular reasoning in existing debates. Assumptions about the past, such as reliable memory or entropy direction, often underpin claims that then validate those same assumptions. Wolpert, Rovelli, and Scharnhorst aim to clarify these hidden structures without resolving the paradox. Their paper, titled 'Disentangling Boltzmann Brains, the Time-Asymmetry of Memory, and the Second Law,' was published in Entropy (2025; 27(12): 1227).