The paper provides a reconstruction of proof by contradiction in Kant’s pure general logic. A seemingly less-explored point of view on this topic is how apagogical proof can account for the formal truth of a judgement. Integrating the argument held by Kjosavik (2019), I intend to highlight how one can use proof by contradiction, conceived as a modus tollens, to establish the logical actuality (logical or formal truth) of a cognition. Although one might agree on the capacity of the proof to prove formal falsity, the logical actuality of a judgement is assessable based on a logically grounded judgement and, as for transcendental logic, this cognitive operation has to presuppose the real possibility of an object.
In this essay, I discuss three readings of Descartes’ Meditations. According to the first reading, “I exist” is for Descartes the foundation of our knowledge. This reading is dismissed on the grounds that, in his view, as long as God’s existence is not proven there is a good reason to doubt this proposition. Proponents of the second reading claim that there are two kinds of Cartesian knowledge: perfect and imperfect knowledge. The meditator has imperfect knowledge of “I exist” before God’s existence is proven. Subsequently, she acquires perfect knowledge of various metaphysical theorems. This reading is repudiated, too. I argue for a third reading, according to which “I think” – and not “I exist” – is the foundation of our knowledge.
This paper examines the terms ‘elenchos’ and ‘elenchō’ as they occur in the Sophist in order to reveal a refined view of elenchos as a philosophical method. The explicit discussion of elenchos as a method in 226a6–231b8 must be read together with other passages described by these terms. Once this is done, it shall be seen that there are two types of elenchus employed in several ways. The first type, which I identify with the familiar Socratic elenchus, is used to purge false opinions or to arrive at plausible answers to philosophical difficulties. The second type, which appears to be the Stranger’s own method, is used to positively disclose relations between Forms. On this reading, elenchos is not merely destructive or preparatory for dialectic; it also forms a part of it.