Logic is usually thought to concern itself only with features that sentences and arguments possess in virtue of their logical structures or forms. The logical form of a sentence or argument is determined by its syntactic or semantic structure and by the placement of certain expressions called “logical constants.”[1] Thus, for example, the sentences Every boy loves some girl. and Some boy loves every girl. are thought to differ in logical form, even though they share a common syntactic and semantic (...) structure, because they differ in the placement of the logical constants “every” and “some”. By contrast, the sentences Every girl loves some boy. and Every boy loves some girl. are thought to have the same logical form, because “girl” and “boy” are not logical constants. Thus, in order to settle questions about logical form, and ultimately about which arguments are logically valid and which sentences logically true, we must distinguish the “logical constants” of a language from its nonlogical expressions. (shrink)

In Epicurean cosmology, material reconstitution, or palingenesis (παλιγγενεσία) is the necessary consequence of the infinity of time and the eternity of atoms. I examine Lucretius’ treatment of this phenomenon (DRN 3.843–864) and consider the extent to which his view enables us to develop an Epicurean response to the question: what makes a person at two different times one and the same person? I offer a reading of this passage in the light of modern accounts of persistence and identity, and what (...) Lucretius states in Books 3 and 4 about memory and the soul’s motions. Guided by the metaphysical implications of this analysis, I determine the type of relation which, according to Lucretius, holds between the mental and the physical. (shrink)