Gregory Landini

Simple-type theory is widely regarded as inadequate to capture the metaphysics of mathematics. The problem, however, is not that some kinds of structure cannot be studied within simple-type theory. Even structures that violate simple-types are isomorphic to structures that can be studied in simple-type theory. In disputes over the logicist foundations of mathematics, the central issue concerns the problem that simple-type theory fails to assure an infinity of natural numbers as objects. This paper argues that the problem of infinity is based on a metaphysical prejudice in favor of numbers as objects — a prejudice that mathematics can get along without.

This dissertation is a study in the comparative formal ontology of fiction. We deal primarily with the alternative ontological frameworks of Alexius Meinong and early Bertrand Russell as each appears in or has influenced the development of intensional logics reconstructing their basic insights. Our aim is to develop an early Russellian account of fiction--an account that can handle the semantics of stories about any manner of "object" of thought, purple gnomes, "round-squares", paradoxical sets, or anything else one might imagine. We develop such an account of fiction from within the type-free intensional logic HST*D), which is a theory of nominalized predicates formulated by Professor Nino Cocchiarella. ;Our Russellian theory is compared with reconstructions of Meinongian views, for example, Terence Parsons' Nonexistent Objects, and Edward Zalta'sObjects. These frameworks present intensional logics which formalize alternative approaches to a Meinongian theory of objects; the former adopts a distinction in kinds of predicates, the latter distinguishes modes of predication. It is found that the valuable applications of both Meinongian frameworks are captured in our early Russellian theory--and without the oddities of Meinongianism. ;The Meinogian regards all reference in our common place intentional activities such as planning, the framing of scientific hypotheses, story telling, deceiving, and the like, as semantically on par. He thus introduces nonexistents, both possible and impossible, as legitimate concrete objects "before the mind". In contrast, our Russellian account treats "reference to the nonexistent" as a part of a general account of nominalization to the linguistic expressions we have for denoting concepts which purport to refer. In this way, we provide new insights for resolving perplexing issues involved in formulating the semantics of fiction, and of natural language in general. It is revealed by comparing our Russellian approach with Hector-Neri Castaneda's Guise Theory, that the representation of the "content" of thought requires only that we represent the conceptual activity of thought, and not that we postulate objects, intentional and otherwise, which are literally "before" the mind. Thus, our Russellian account has many important applications for the development of a general semantics for natural language, and for the philosophy of mind

This paper offers an interpretation of Russell's multiple-relation theory of judgment which characterizes it as direct application of the 1905 theory of definite descriptions. The paper maintains that it was by regarding propositional symbols (when occurring as subordinate clauses) as disguised descriptions of complexes, that Russell generated the philosophical explanation of the hierarchy of orders and the ramified theory of types of _Principia mathematica (1910). The interpretation provides a new understanding of Russell's abandoned book _Theory of Knowledge (1913), the 'direction problems' and Wittgenstein's criticisms

Zermelo once wrote that he had anticipated Russell's contradiction of the set of all sets that are not members of themselves. Is this sufficient for having anticipated Russell's Paradox — the paradox that revealed the untenability of the logical notion of a set as an extension? This paper argues that it is not sufficient and offers criteria that are necessary and sufficient for having discovered Russell's Paradox. It is shown that there is ample evidence that Russell satisfied the criteria and that Zermelo did not

In his "Grundgesetze", Frege hints that prior to his theory that cardinal numbers are objects he had an "almost completed" manuscript on cardinals. Taking this early theory to have been an account of cardinals as second-level functions, this paper works out the significance of the fact that Frege's cardinal numbers is a theory of concept-correlates. Frege held that, where n > 2, there is a one—one correlation between each n-level function and an n—1 level function, and a one—one correlation between each first-level function and an object. Applied to cardinals, the correlation offers new answers to some perplexing features of Frege's philosophy. It is shown that within Frege's concept-script, a generalized form of Hume's Principle is equivalent to Russell's Principle ofion — a principle Russell employed to demonstrate the inadequacy of definition by abstraction. Accordingly, Frege's rejection of definition of cardinal number by Hume's Principle parallels Russell's objection to definition by abstraction. Frege's correlation thesis reveals that he has a way of meeting the structuralist challenge that it is arithmetic, and not a privileged progression of objects, that matters to the finite cardinals.

This paper examines Russell's substitutional theory of classes and relations, and its influence on the development of the theory of logical types between the years 1906 and the publication of Principia Mathematica (volume I) in 1910. The substitutional theory proves to have been much more influential on Russell's writings than has been hitherto thought. After a brief introduction, the paper traces Russell's published works on type-theory up to Principia. Each is interpreted as presenting a version or modification of the substitutional theory. New motivations for Russell's 1908 axiom of infinity and axiom of reducibility are revealed

This article compares the theory of Meinongian objects proposed by Edward Zalta with a theory of fiction formulated within an early Russellian framework. The Russellian framework is the second-order intensional logic proposed by Nino B. Cocchiarelly as a reconstruction of the form of Logicism Russell was examining shortly after writing The Principles of Mathematics. A Russellian theory of denoting concepts is developed in this intensional logic and applied as a theory of the "objects' of fiction. The framework retains the Orthodox early Russellian ontology of existents, possible non-existents, and properties and relations in intension. This avoids the assumption, found in Meinongian theories, of impossible and incomplete objects. It also obviates the need to preserve consistency by distinguishing a new "mode of predication", or a "distinction in kinds of predicates". Thus, it is argued that an early Russellian theory forms a powerful rival to a Meinongian theory of objects.

In his new introduction to the 1925 second edition of Principia Mathematica, Russell maintained that by adopting Wittgenstein's idea that a logically perfect language should be extensional mathematical induction could be rectified for finite cardinals without the axiom of reducibility. In an Appendix B, Russell set forth a proof. Godel caught a defect in the proof at *89.16, so that the matter of rectification remained open. Myhill later arrived at a negative result: Principia with extensionality principles and without reducibility cannot recover mathematical induction. The finite cardinals are indefinable in it. This paper shows that while Gödel and Myhill are correct, Russell was not wrong. The 1925 system employs a different grammar than the original Principia. A new proof for *89.16 is given and induction is recovered

The second printing of Principia Mathematica in 1925 offered Russell an occasion to assess some criticisms of the Principia and make some suggestions for possible improvements. In Appendix A, Russell offered *8 as a new quantification theory to replace *9 of the original text. As Russell explained in the new introduction to the second edition, the system of *8 sets out quantification theory without free variables. Unfortunately, the system has not been well understood. This paper shows that Russell successfully antedates Quine's system of quantification theory without free variables. It is shown as well, that as with Quine's system, a slight modification yields a quantification theory inclusive of the empty domain

This book explores an important central thread that unifies Russell's thoughts on logic in two works previously considered at odds with each other, the Principles of Mathematics and the later Principia Mathematica. This thread is Russell's doctrine that logic is an absolutely general science and that any calculus for it must embrace wholly unrestricted variables. The heart of Landini's book is a careful analysis of Russell's largely unpublished "substitutional" theory. On Landini's showing, the substitutional theory reveals the unity of Russell's philosophy of logic and offers new avenues for a genuine solution of the paradoxes plaguing Logicism.

It is well known that in _Principia Mathematica_ Russell offers a theory of definite descriptions and holds that ‘existence’ is not a property. It is less well known that in “On Denoting” he discusses the version of Anselm’s ontological argument for God formulated by Descartes, accepting the premiss “Existence is a perfection” and assessing the argument as valid but question-begging. This is different from his later comments in _A History of Western Philosophy_ which find the argument invalid. Indeed, given the sanctions of _Principia_, one might have thought he would find the argument logically ungrammatical. This paper shows how Russell might formulate and evaluate Anselm’s ontological argument and the version offered by Descartes in a way that avoids the conflict.1.

Wittgenstein's Tractatus has generated many interpretations since its publication in 1921, but over the years a consensus has developed concerning its criticisms of Russell's philosophy. In Wittgenstein's Apprenticeship with Russell, Gregory Landini draws extensively from his work on Russell's unpublished manuscripts to show that the consensus characterises Russell with positions he did not hold. Using a careful analysis of Wittgenstein's writings he traces the 'Doctrine of Showing' and the 'fundamental idea' of the Tractatus to Russell's logical atomist research program, which dissolves philosophical problems by employing variables with structure. He argues that Russell and his apprentice Wittgenstein were allies in a research program that makes logical analysis and reconstruction the essence of philosophy. His sharp and controversial study will be essential reading for all who are interested in this rich period in the history of analytic philosophy.