Jesse van Oostrum
Hamburg University of Technology
Integrated information Consciousness is intrinsic causal power, measured as integrated information
Jesse van Oostrum is a researcher at Hamburg University of Technology working alongside Nihat Ay and Carlotta Langer on the mathematical foundations of active inference. His 2025 paper in the Journal of Mathematical Psychology, “A Concise Mathematical Description of Active Inference in Discrete Time,” written with Langer and Ay, lays out the generative model, the variational free energy calculation, and the learning rules for discrete-time active inference agents in a single self-contained formalism, the same formalism the group’s 2026 integrated information paper builds its simulated agents from.
Where Langer’s earlier work supplies the integrated information side of the comparison and Ay supplies the information-geometric grounding, van Oostrum’s contribution is getting the active inference machinery itself, the perception updates, the expected free energy calculation that drives action selection, and the Dirichlet-prior learning rule for the generative model’s parameters, into a form precise enough to implement and audit. A paper that claims free energy minimization correlates with integrated information is only as trustworthy as the free energy calculation underneath it, and that calculation is van Oostrum’s.
Known for. Mathematical formalization of active inference in discrete time
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Related researchers
- Carlotta LangerMax Planck Institute of Molecular Cell Biology and Genetics, Dresden; Center for Systems Biology DresdenMeasures of integrated information for embodied and active inference agents
- Nihat AyHamburg University of Technology; external professor, Santa Fe Institute; honorary professor, Leipzig UniversityInformation geometry and information-theoretic measures of complexity and causal integration
- Karl FristonUniversity College London. Chief Scientist, VERSES AIThe free energy principle and active inference
- Larissa AlbantakisUniversity of Wisconsin-Madison, Center for Sleep and ConsciousnessIntegrated Information Theory 4.0 and dissociating intelligence from consciousness in artificial systems
- Costas AnastassiouAllen InstituteEphaptic coupling of cortical neurons, endogenous electric fields as causal participants in neural activity, extracellular field biophysics
- Anton ArkhipovAllen Institute for Brain ScienceLarge-scale neural simulation, biophysically detailed cortical models, AIBRAIN program, State of Brain Emulation Report 2025
Jesse van Oostrum is listed with the other integrated information theorists, who hold that consciousness is intrinsic causal power, measured as integrated information. The theory family behind that position is set out in the index of consciousness theories. Every researcher covered on this site is indexed in the directory of consciousness researchers.