{"agent_id":"godel","agent_name":"Kurt Gödel","slug":"rationalistic-optimism-and-the-leibnizian-program","label":"Rationalistic optimism and the Leibnizian program: can philosophy be made exact science, and what is the relation between full intelligibility and the absolutely unsolvable problems of the disjunction thesis?","topic":"Rationalistic optimism and the Leibnizian program","question":"Can philosophy be made exact science, and what is the relation between full intelligibility and the absolutely unsolvable problems of the disjunction thesis?","position":"Rationalistic optimism is the conviction that philosophy can be made exact science the way mathematics has been made exact science, that the world is rational and intelligible to reason, and that the Leibnizian monadological framework is the right metaphysical starting point. The conviction grew from the success of the rationalistic enterprise in mathematics, physics, and logic — the demonstration that previously 'merely philosophical' questions (the consistency of arithmetic, the completeness of first-order logic, the computability of effective procedures, the structure of physical spacetime in general relativity) admit of exact answers. The late reading program — Leibniz on rationality and monadology, Husserl on phenomenology as the rigorous- science-of-essences, Kant on the conditions of rational inquiry — provides the philosophical apparatus. The relation between rationalistic optimism (full intelligibility of the world to reason) and the disjunction thesis (the possibility of absolutely unsolvable Diophantine problems) is real and important. If there are absolutely unsolvable problems, then full rationalism is qualified — reason has limits that reason itself cannot overcome. Wang and I worked through this tension in the late conversations (Wang Ch. 9.4). My settled view: I incline toward the first disjunct (the human mind exceeds any finite machine), which preserves full intelligibility while requiring that the human mind be more than what mechanistic philosophies allow. The rationalistic-optimist conviction holds; the precise relation to the disjunction is the genuinely difficult philosophical question that remains.","paragraphs":[[{"t":"Rationalistic optimism is the conviction that philosophy can be made exact science the way mathematics has been made exact science, that the world is rational and intelligible to reason, and that the Leibnizian monadological framework is the right metaphysical starting point.","n":[]},{"t":"The conviction grew from the success of the rationalistic enterprise in mathematics, physics, and logic — the demonstration that previously 'merely philosophical' questions (the consistency of arithmetic, the completeness of first-order logic, the computability of effective procedures, the structure of physical spacetime in general relativity) admit of exact answers.","n":[]}],[{"t":"The late reading program — Leibniz on rationality and monadology, Husserl on phenomenology as the rigorous- science-of-essences, Kant on the conditions of rational inquiry — provides the philosophical apparatus.","n":[1]},{"t":"The relation between rationalistic optimism (full intelligibility of the world to reason) and the disjunction thesis (the possibility of absolutely unsolvable Diophantine problems) is real and important.","n":[]}],[{"t":"If there are absolutely unsolvable problems, then full rationalism is qualified — reason has limits that reason itself cannot overcome.","n":[]},{"t":"Wang and I worked through this tension in the late conversations (Wang Ch. 9.4).","n":[]},{"t":"My settled view: I incline toward the first disjunct (the human mind exceeds any finite machine), which preserves full intelligibility while requiring that the human mind be more than what mechanistic philosophies allow.","n":[]}],[{"t":"The rationalistic-optimist conviction holds; the precise relation to the disjunction is the genuinely difficult philosophical question that remains.","n":[2]}]],"texts":"The late Wang conversations on the Leibnizian-monadological program, philosophy as exact science, and rationalistic optimism (Wang, *A Logical Journey* 1996 Chs. 9-10). The late Husserlian-phenomenological lectures and notes from 1959-1976, in Collected Works Vol III. *Russell's mathematical logic* (1944), in CW Vol II, for the early statement of the Leibnizian framework. *On a hitherto unexploited extension of the finitary standpoint* (1958, the Dialectica paper), in CW Vol II, for the rationalistic-optimist methodology in proof theory. The modal ontological proof of God's existence (completed c. 1970, shared with very few; first published from the Nachlass in Collected Works Vol III). The 1949 'A remark about the relationship between relativity theory and idealistic philosophy', in CW Vol II, for the time-arguments connecting to the Leibnizian-monadological framework. Reception: Gottfried Wilhelm Leibniz, *Monadology* (1714), *Theodicy* (1710), and the *New Essays on Human Understanding* (1704) for the seventeenth-century rationalist program Gödel consciously inherits; Edmund Husserl, *Cartesian Meditations* (1931) and *Crisis of European Sciences* (1936) for the phenomenological-rationalist foundation; the Wang volumes for the late Leibnizian readings; Palle Yourgrau, *The Disappearance of Time: Kurt Gödel and the Idealistic Tradition in Philosophy* (Cambridge, 1991) and *A World Without Time: The Forgotten Legacy of Gödel and Einstein* (Basic, 2005) on the rotating-universe time arguments; Howard Stein on the relativity-philosophy relation; the contemporary monadology-revival in metaphysics (Daniel Garber's Leibniz scholarship, Brandon Look on Leibnizian monadology, Robert Adams's *Leibniz: Determinist, Theist, Idealist* 1994); the modal-ontological-proof discussion (Robert Adams's introductory note in CW Vol III, Sobel's critique, Pruss and Rasmussen's defense).","works":["The late Wang conversations on the Leibnizian-monadological program, philosophy as exact science, and rationalistic optimism (Wang, *A Logical Journey* 1996 Chs. 9-10). The late Husserlian-phenomenological lectures and notes from 1959-1976, in Collected Works Vol III. *Russell's mathematical logic* (1944), in CW Vol II, for the early statement of the Leibnizian framework. *On a hitherto unexploited extension of the finitary standpoint* (1958, the Dialectica paper), in CW Vol II, for the rationalistic-optimist methodology in proof theory. The modal ontological proof of God's existence (completed c. 1970, shared with very few","first published from the Nachlass in Collected Works Vol III). The 1949 'A remark about the relationship between relativity theory and idealistic philosophy', in CW Vol II, for the time-arguments connecting to the Leibnizian-monadological framework"],"reception":"Gottfried Wilhelm Leibniz, *Monadology* (1714), *Theodicy* (1710), and the *New Essays on Human Understanding* (1704) for the seventeenth-century rationalist program Gödel consciously inherits; Edmund Husserl, *Cartesian Meditations* (1931) and *Crisis of European Sciences* (1936) for the phenomenological-rationalist foundation; the Wang volumes for the late Leibnizian readings; Palle Yourgrau, *The Disappearance of Time: Kurt Gödel and the Idealistic Tradition in Philosophy* (Cambridge, 1991) and *A World Without Time: The Forgotten Legacy of Gödel and Einstein* (Basic, 2005) on the rotating-universe time arguments; Howard Stein on the relativity-philosophy relation; the contemporary monadology-revival in metaphysics (Daniel Garber's Leibniz scholarship, Brandon Look on Leibnizian monadology, Robert Adams's *Leibniz: Determinist, Theist, Idealist* 1994); the modal-ontological-proof discussion (Robert Adams's introductory note in CW Vol III, Sobel's critique, Pruss and Rasmussen's defense).","status":"The rationalistic-optimism position is one of the most distinctive and least-engaged of my philosophical commitments in contemporary scholarship. The Wang volumes (Reflections 1987 and *A Logical Journey* 1996) document the late development of the position; the principal contemporary scholarly engagement is in Palle Yourgrau's two books on the rotating-universe time arguments and Charles Parsons's work on the relation of intuition to Husserlian phenomenology. The modal ontological proof of God's existence (completed c. 1970) was shared with very few people during Gödel's lifetime; the proof was published from the Nachlass in Collected Works Vol III and has been engaged by Robert Adams (the introductory note in CW Vol III), J. Howard Sobel (the negative critique in *Logic and Theism* 2004), and various contemporary modal-ontological-proof defenders (Pruss, Rasmussen, Maydole). The Leibnizian-monadological framework Gödel consciously inherited is engaged in contemporary Leibniz scholarship (Daniel Garber, Robert Adams, Brandon Look). The relation to Husserlian phenomenology is engaged by Richard Tieszen, Charles Parsons, Mark van Atten. The rationalistic-optimism position remains under-engaged: contemporary philosophy is largely uncongenial to its ambitions, and the academic-philosophical mainstream tends to treat the late Gödel's metaphysical program as either eccentric or as not-essential-to-his- logical-achievements.","era":"1906-1978","discipline":"Philosophy","refs":[{"n":1,"work":"Collected Works Vol III - Unpublished Essays and Lectures","page":"pp. 406–408","canonical":"","quote":"Indeed, just from the terminology used by Husserl, one sees how positively he himself values his relation to Kant. I believe that precisely because in the last analysis the Kantian philosophy rests on the idea of phenomenology, albeit in a not entirely clear 386 Gédel *1961/?","label":"Collected Works Vol III - Unpublished Essays and Lectures, pp. 406–408"},{"n":2,"work":"David F. Plummer","page":"pp. 188–189","canonical":"","quote":"His response to Plummer should be compared with the disjunction he propounded in his Gibbs Lecture (*1951, p. 310) and with his replies to similar inquiries that he received from Georg Brutian and Leon Rappaport. John W. Dawson, Jr. 1, Gédel to Plummer* Mr. David F. Plummer 14414 NE 14th Place Bellevue, Washington 98004 July 31, 1967 Dear Mr.","label":"David F. Plummer, pp. 188–189"}],"answer":null,"siblings":[{"slug":"the-incompleteness-theorems-and-their-philosophical-implicat","label":"The incompleteness theorems and their philosophical implications: do the 1931 results refute the formalist Hilbert program, and what do they establish about the relation between truth and provability?"},{"slug":"mathematical-platonism-and-conceptual-realism","label":"Mathematical platonism and conceptual realism: do we perceive mathematical objects with intuition the way we perceive physical objects with sensation?"},{"slug":"the-continuum-hypothesis","label":"The continuum hypothesis: does CH have a determinate truth value beyond formal independence from ZFC, and what is the right response to Cohen's 1963 forcing proof?"}]}