Alexander V. Gheorghiu

Alexander V. Gheorghiu is a logician whose research sits at the intersection of mathematical logic, philosophy, and computer science. He is a New Frontiers Fellow in the School of Electronics and Computer Science at the University of Southampton, and an Honorary Research Fellow in the Department of Computer Science at University College London.

His primary research focus is proof-theoretic semantics — a programme in the philosophy of logic that treats inference, rather than truth, as semantically fundamental. Rooted in the work of Gentzen, Dummett, and Prawitz, this approach holds that the meaning of a logical expression is constituted by the rules governing its use in proofs. Gheorghiu has extended this programme to classical logic, first-order logic, and substructural logics including the logic of bunched implications, developing a general base-extension framework for proof-theoretic validity.

More broadly, he is interested in what formal reasoning reveals about artificial intelligence. A core claim of his recent work is that the distinction between statistical prediction and genuine reasoning is formally precise: a system that cannot ground its outputs in principled inferential steps does not, in any robust sense, reason. This has practical consequences for how we design, evaluate, and govern intelligent systems.

He has been an invited speaker at the Banff International Research Station, the Dagstuhl Seminar on Proof-theoretic Semantics, and the Center for Logic, Language, and Cognition at Peking University. He organises the international Symposium on Proof-theoretic Semantics and serves as a referee for leading journals including Logic in Computer Science, Studia Logica, and Topoi.

His public writing on logic, mathematics, and artificial intelligence has appeared in the Times Literary Supplement, Mathematics Today, and The Conversation. His 2025 essay “High School Algebra and the Limits of AI” received the Graham Hoare Prize from the Institute of Mathematics and its Applications.