Peter Ludlow (/ˈlʌdloʊ/; born January 16, 1957), who also writes under the pseudonyms Urizenus Sklar and EJ Spode, is an American philosopher. He is noted for interdisciplinary work on the interface of linguistics and philosophy—in particular on the philosophical foundations of Noam Chomsky's theory of generative linguistics and on the foundations of the theory of meaning in linguistic semantics. He has worked on the application of analytic philosophy of language to topics in epistemology, metaphysics, and logic, among other areas.
Ludlow has also established a research program outside of philosophy and linguistics. Here, his research areas include conceptual issues in cyberspace, particularly questions about cyber-rights and the emergence of laws and governance structures in and for virtual communities, including online games, and as such he is also noted for influential contributions to legal informatics. In recent years Ludlow has written nonacademic essays on hacktivist culture and related phenomena such as WikiLeaks and the conceptual limits of blockchain technologies. Most recently he has argued that blockchain-based communities will be the new organizing technologies for human governance, replacing the 400 year old Westphalian system of the nation state.