@article{Lenzen_2019, title={Leibniz’s laws of consistency and the philosophical foundations of connexive logic}, volume={28}, url={https://apcz.umk.pl/LLP/article/view/LLP.2019.004}, DOI={10.12775/LLP.2019.004}, abstractNote={<div><p>As an extension of the traditional theory of the syllogism, Leibniz’s algebra of concepts is built up from the term-logical operators of conjunction, negation, and the relation of containment.</p><p>Leibniz’s laws of consistency state that no concept contains its own negation, and that if concept A contains concept B, then A cannot also contain Not-B. Leibniz believed that these principles would be universally valid, but he eventually discovered that they have to be restricted to self-consistent concepts.</p><p>This result is of utmost importance for the philosophical foundations of connexive logic, i.e. for the question how far either “Aristotle’s Thesis”, ¬(α → ¬α), or “Boethius’s Thesis”, (α → β) → ¬(α → ¬β), should be accepted as reasonable principles of a logic of conditionals.</p></div><p> </p>}, number={3}, journal={Logic and Logical Philosophy}, author={Lenzen, Wolfgang}, year={2019}, month={Jan.}, pages={537–551} }