Imre Lakatos' philosophical and scientific papers are published here in two volumes.Volume I brings together his very influential but scattered papers on the philosophy of the physical sciences, and includes one important unpublished essay on the effect of Newton's scientific achievement. Volume 2 presents his work on the philosophy of mathematics together with some critical essays on contemporary philosophers of science.Volume I brings together his very influential but scattered papers on the philosophy of the physical sciences, and includes one important unpublished essay on the effect of Newton's scientific achievement. Volume 2 presents his work on the philosophy of mathematics together with some critical essays on contemporary philosophers of science.Imre Lakatos' philosophical and scientific papers are published here in two volumes. Volume I brings together his very influential but scattered papers on the philosophy of the physical sciences, and includes one important unpublished essay on the effect of Newton's scientific achievement. Volume 2 presents his work on the philosophy of mathematics (much of it unpublished), together with some critical essays on contemporary philosophers of science and some famous polemical writings on political and educational issues.Editors' introduction; Part I. Philosophy of Mathematics: 1. Infinite regress and foundations of mathematics; 2. A renaissance of empiricism in the recent philosophy of mathematics?; 3. Cauchy and the continuum: the significance of non-standard analysis for the history and philosophy of mathematics; 4. What does a mathematical proof prove?; 5. The method of analysis-synthesis; Part II. Critical Papers: 6. The problem of appraising scientific theories: three approaches; 7. Necessity, Kineale and Popper; 8. Changes in the problem of inductive logic; 9. On Popperian historiography; 10. Anomalies versus 'crucial experiments'; 11. Understanding Toulmin; Part III. Science and Education: 12. A letter to the dl#µ