The discussions which follow rest on a distinction, first expounded by Husserl, between formal logic and formal ontology. The former concerns itself with (formal) meaning-structures; the latter with formal structures amongst objects and their parts. The paper attempts to show how, when formal ontological considerations are brought into play, contemporary extensionalist theories of part and whole, and above all the mereology of Leniewski, can be generalised to embrace not only relations between concrete objects and object-pieces, but also relations between what (...) we shall call dependent parts or moments. A two-dimensional formal language is canvassed for the resultant ontological theory, a language which owes more to the tradition of Euler, Boole and Venn than to the quantifier-centred languages which have predominated amongst analytic philosophers since the time of Frege and Russell. Analytic philosophical arguments against moments, and against the entire project of a formal ontology, are considered and rejected. The paper concludes with a brief account of some applications of the theory presented. (shrink)

The history of modern logic is usually written as the history of mathematical or, more general, symbolic logic. As such it was created by mathematicians. Not regarding its anticipations in Scholastic logic and in the rationalistic era, its continuous development began with George Boole's The Mathematical Analysis of Logic of 1847, and it became a mathematical subdiscipline in the early 20th century. This style of presentation cuts off one eminent line of development, the philosophical development of logic, although logic is (...) evidently one of the basic disciplines of philosophy. One needs only to recall some of the standard 19th century definitions of logic as, e.g., the art and science of reasoning (Whateley) or as giving the normative rules of correct reasoning (Herbart). In the paper the relationship between the philosophical and the mathematical development of logic will be discussed. Answers to the following questions will be provided: 1. What were the reasons for the philosophers' lack of interest in formal logic? 2. What were the reasons for the mathematicians' interest in logic? 3. What did "logic reform" mean in the 19th century? Were the systems of mathematical logic initially regarded as contributions to a reform of logic? 4. Was mathematical logic regarded as art, as science or as both? (shrink)

This article presents a novel reading of Descartes’s critique of the traditional syllogistic. The reading differs from those previously presented by scholars who regard Descartes’s critique as a version of a well-known argument: that syllogisms are circular or non-ampliative and thus trivial. It is argued that Descartes did not see syllogisms as defective in themselves. For him the problem was rather that anyone considering a valid and informative syllogism must already know, by an intuition wholly independent of the syllogism, that (...) the conclusion follows from the premises. Moreover, without such an intuition the syllogistic on its own is incapable of determining whether the consequence truly holds. Thus the syllogistic is useless unless accompanied by an intuition that renders it otiose. This reading of Descartes’s view is supported and explained by examples drawn from Descartes’s writing and from the Port-Royal Logic—one of the first attempts to develop a logical system on Cartesian principles. (shrink)

Symbolic logic faced great difficulties in its early stage of development in order to acquire recognition of its utility for the needs of science and society. The aim of this paper is to discuss an early attempt by the British logician Lewis Carroll (1832–1898) to promote symbolic logic as a social good. This examination is achieved in three phases: first, Carroll’s belief in the social utility of logic, broadly understood, is demonstrated by his numerous interventions to fight fallacious reasoning in (...) public debates. Then, Carroll’s attempts to promote symbolic logic, specifically, are revealed through his work on a treatise that would make the subject accessible to a wide and young audience. Finally, it is argued that Carroll’s ideal of logic as a common good influenced the logical methods he invented and allowed him to tackle more efficiently some problems that resisted to early symbolic logicians. (shrink)

But logic as it stands, e.g. in Principia Mathematica, can quite well be applied to our ordinary propositions; e.g. from ‘All men are mortal’ and ‘Socrates is a man’ there follows according to this logic ‘Socrates is mortal’, which is obviously correct, even though I equally obviously do not know what structure is possessed by the thing Socrates or the property of mortality. Here they just function as simple objects.

Lewis Carroll offers an interesting perspective on the development of early symbolic logic. On the one hand, he makes a characteristic case of a logician who worked on symbolic methods...

A new diagram system \ where properties are fundamental and an object exists only w.r.t a property is presented. This work modifies both in syntax and semantics the system \ proposed by Choudhury and Chakraborty to picturise and address issues connected with open universe. Semantics for the current system is given. Soundness and completeness w.r.t the semantics are established.