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SORITES, ISSN 1135-1349

Issue #04. February 1996. Pp. 4-6

Abstracts of the Papers

Copyright (C) by SORITES and the authors

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Abstracts of the Papers

A Classicist's Note on Two-, Three-, and Four-Valued Logic

Joseph S. Fulda

The classical logician's principal dictum, «A proposition is either true or false, not neither, and not both,» still leaves considerable room for multi-valued logic.


One for Leibniz

Vernon Pratt

For Leibniz, it was a requirement upon the `fundamentally real' to have a `principle of unity'. What does this mean?

One general point is that Substance cannot be understood as pure extension. But there is a particular point about cohesion: a real thing had to have some means by which its parts were stuck together. But Leibniz' insistence on `unity' is also an insistence on indivisibility. Under this head there is first the point that there appears to be a contradiction between extension and being incapable of being cut in two. Second, Leibniz uses the notion of `indivisibility' to mark the following distinction among things made up of parts: (a) those which cannot be split without being destroyed; and (b) the rest (which are mere `aggregates'). To be `indivisible' is to be of the first type. Leibniz' insistence that the truly real must be `indivisible' is then his insistence that the truly real, if it is made up of parts, must be a thing with `integrity', i.e. not an aggregate.

What does Leibniz think of as the connection between what is truly real and the possession of `integrity'? He took from Scholasticism the doctrine that action is necessarily attributed to a substance having `integrity', contructing what was in effect a theory of action with two parts: (a) only self-subsistent substances can act; and (b) an action is an origination of change. Leibniz thus insists that self-subsistent substances must be indivisible, in the sense that they cannot be mere aggregates. Aggregates cannot act, and self-subsistence in effect is the capacity for action. This is the most fundamental reason Leibniz had for insisting that the truly real must have a `principle of unity'.

It is misleading to speak of Leibniz reintroducing the Scholastic form-and-matter conception of substance for the following reasons:

(a) the Scholastic `form' precisely lacked a `principle of action'; and

(b) during the period when it is suggested that Leibniz' conception was essentially Scholastic he was defending the view that what his `form' informed was not matter at all but what he called a `metaphysical point'.


Logic and Necessary Being

Matthew McKeon

Yuval Steinitz has argued that, since it is logically possible that there are logically necessary beings, it follows that there is at least one logically necessary being. Steinitz switches the Leibnitzean ontological argument's concern from perfect beings to logically necessary beings. My paper has two primary aims. First, I argue that Steinitz's quick treatment is insufficient to establish the validity of his argument. Secondly, I argue that the correct approach to logical necessity must account for those possible situations in which the meanings of some of the terms in our language might have been different; on such an approach, the premise of Steinitz's argument is false. My remarks here are intended to add to the prima facie plausibility of Hume's claim that logic has no existential implications.


Aristotelian and Modern Logic

Katalin Havas

Is modern logic an improvement on Aristotelian logic or is there some other relationship between the two? In which sense is modern logic more advanced than Aristotelian logic? Is logic a cummulative developing discipline or is the progress in the course of the history of logic somehow different from the cumulatively developing processes? Are these logics based on different -- mutually untranslatable -- paradigms? The paper analyzes these questions in connection with some more general problems of the philosophy of science.


On Behalf of the Fool: Moore and Our Knowledge of the Existence

of Material Objects

Edward N. Martin

In this paper I argue that G.E. Moore's naturalism (combined with his sense-data theory) falls prey to the charge, leveled recently by Plantinga, that Moore doesn't know whether his belief-forming mechanisms are functioning properly when he says he knows a pencil (or his hand) exists. Help from Alston may be sought in response to criticisms, but these are not sufficient to vindicate Moore's form of naturalism.