Andrea Iacona

This paper deals with the question of what it is for a quantifier expression to be vague. First it draws a distinction between two senses in which quantifier expressions may be said to be vague, and provides an account of the distinction which rests on independently grounded assumptions. Then it suggests that, if some further assumptions are granted, the difference between the two senses considered can be represented at the formal level. Finally, it outlines some implications of the account provided which bear on three debated issues concerning quantification.

Classical logic rests on the assumption that there are two mutually exclusive and jointly exhaustive truth values. This assumption has always been surrounded by philosophical controversy. Doubts have been raised about its legitimacy, and hence about the legitimacy of classical logic. Usually, the assumption is stated in the form of a general principle, namely the principle that every proposition is either true or false. Then, the philosophical controversy is often framed in terms of the question whether every proposition is either true or false. The main purpose of the paper is to show that there is something wrong in this way of putting things. The point is that the common way of understanding the controversial assumption is misconceived, as it rests on a wrong picture of propositions. In the first part of the paper I outline this picture and I argue against it. In the second part I sketch a different picture of propositions and I suggest how this leads to conceive the issue of classical logic in different terms.

One of the most common strategies in philosophical dispute is that of accusing the opponent of begging the question, that is, of assuming or presupposing what is to be proved. Thus, it happens quite often that the credibility of a philosophical argument is infected by the suspicion of begging the question. In many cases it is an open question whether the suspicion is grounded, and the answer lurks somewhere in the dark of what the proponent of the argument does not say. This is why it may take years, or even centuries, before the begging of the question is brought to light. But few philosophers would deny that once it is established that a certain argument begs the question, that argument has to be rejected without hesitation: question-begging arguments are bad arguments, hence one should not appeal to them. Logicians traditionally classify begging the question as a fallacy, that is, as a bad reasoning that seems good at first sight. The fallacy is known under the name of petitio principii. This paper originated in our dissatisfaction with definitions of petitio principii found here and there in logic textbooks. Although it is uncontroversial that there is something wrong with begging the question, it is not clear from those definitions what is wrong.