Abstract
In several works published between 1759 and 1782, Gottfried Ploucquet developed a logical system which deviates from traditional syllogistics in several respects. The most important features – which are critically examined in this paper – comprise:
The „identity-thesis“ maintaining that each affirmative proposition expresses an identity between subject and predicate.
An attempt to refute some of the traditional laws of opposition.
A formalization of the categorical forms by means of the „quantifiers“ ‚O‘ (for ‚Omne‘), ‚Q‘ (for ‚Quoddam‘) and the relations of identity, ‚–‘ and diversity, ‚>‘.
A new theory of conversion.
The „quantification of the predicate“, i.e. the consideration of certain non-categorical forms.
© Copyright 2008 by Walter de Gruyter GmbH & Co. KG, D-10785 Berlin
