Among the many scholars who promoted the revival of learning in western Europe in the early twelfth century, Abelard stands out as a consummate logician, a formidable polemicist and a champion of the value of ancient pagan wisdom for Christian thought. Although he worked within the Aristotelian tradition, his logic deviates significantly from that of Aristotle, particularly in its emphasis on propositions and what propositions say. According to Abelard, the subject matter of logic, including universals such as genera and species, consists of linguistic expressions, not of the things these expressions talk about. However, the objective grounds for logical relationships lie in what these expressions signify, even though they cannot be said to signify any things. Abelard is, then, one of a number of medieval thinkers, often referred to in later times as ‘nominalists’, who argued against turning logic and semantics into some sort of science of the ‘real’, a kind of metaphysics. It was Abelard’s view that logic was, along with grammar and rhetoric, one of the sciences of language.
In ethics, Abelard defended a view in which moral merit and moral sin depend entirely on whether one’s intentions express respect for the good or contempt for it, and not at all on one’s desires, whether the deed is actually carried out, or even whether the deed is in fact something that ought or ought not be done.
Abelard did not believe that the doctrines of Christian faith could be proved by logically compelling arguments, but rational argumentation, he thought, could be used both to refute attacks on Christian doctrine and to provide arguments that would appeal to those who were attracted to high moral ideals. With arguments of this latter sort, he defended the rationalist positions that nothing occurs without a reason and that God cannot do anything other than what he does do.
II. On the spectra of metalloids— Spectrum of Oxygen