Alexander V. Gheorghiu

Proof-theoretic semantics is a programme in the philosophy of logic that takes inference — rather than truth or reference — as the basic semantic concept. Where classical semantics asks what propositions are true, proof-theoretic semantics asks what follows from what, and why. The meaning of a logical constant such as “and” or “if…then” is given entirely by the rules governing its use in proofs.

This approach, developed in the tradition of Gentzen, Dummett, and Prawitz, has consequences that reach well beyond mathematical logic. It offers a new account of how language acquires meaning, a rigorous framework for evaluating the coherence of logical systems, and a principled basis for asking what genuine reasoning requires — a question that is increasingly urgent as AI systems are asked to explain, justify, and advise.

A central claim of Gheorghiu's work is that the gap between statistical prediction and genuine reasoning is not merely philosophical but formally precise: a system that cannot trace its outputs back to principled inferential steps cannot, in any robust sense, be said to reason. Understanding this distinction is essential for building AI systems that are not just powerful, but interpretable and trustworthy.