This articles discusses the logic, or logic-based, languages required for a full deployment of the SemanticWeb. It presents ten theses addressing 1. the kinds of logic languages needed, 2. data and data processing, 3. semantics, and 4. engineering and rendering issues. The views reported about in this article have been presented at the W3C Workshop on Rule Languages for Interoperability (27-28 April 2005,Washington, D.C., USA, http://www.w3.org/2004/12/rules-ws/).