On Logical Realism from the Perspective of Logical Constants

• Published in: Fu dan xue bao. She hui ke xue ban Vol. 60; no. 2; p. 46
• Main Author: Zangwill, Nick
• Format: Journal Article
• Language: English
• Published: Fudan University 01.04.2018
• Subjects: Analysis; Conjunction fallacy; Logic; Realism (Philosophy)
• ISSN: 0257-0289

I argue that the central logical constants, and, or and not are features of the world, and the words or concepts for these logical constants refer to features of the world. I defend this by appeal to the determining roles of logical constants. I explore the negative consequences of the positive view; logic is not abstract, it is not primary concerned with reasoning or inference or language, and it is not to be explained in terms of truth or truth-tables. In this paper, I describe and defend realism about logic. Three things led me to pursue this idea. First, I came to reflect on logic by thinking about negative properties. I wondered whether not having a property can explain some things. That led me to think about negation. Second, I was surprised by the inadequacy of the first few pages of many logic textbooks, where they try to say what the book is about. There is, in fact, quite a large variety in what is said in those opening pages. More important is that what is said in those pages is very often inadequate (defining validity in terms of necessity, for example). Third, I have a general inclination to realism about any subject matter. I tend to begin with realism and turn away from it only if forced to do so. So when I came to think about logic, realism was my natural first option, and I saw no reason to abandon it. What I call "realism" about logic is a thesis with two elements; first, that certain logical constants are features or constituents of the world; and, second, that logical constants concepts and words have the function of referring to these features or constituents of the world. Here I restrict my focus to an examination of just three central logical constants; and (&) , or (v) and not ([logical not]). I shall not address quantification, identity, conditionals or other phenomena that philosophers classify as "logical. " I shall remain agnostic about the extension of the realist thesis beyond these three logical constants. I shall however comment on the question of the scope of logic at the end of the paper. One common theme running through this paper is a distrust of any general notion of a "logical constant" that assumes that something interesting is shared by the items that it collects together. This paper divides into three sections. In the first, I focus on & and V, and delineate a realist view of these two logical constants. The realist view is developed in terms of Alexander's Principle--showing that & and V have determining roles and also that they have distinctive determining roles. Problems with the realist interpretation of V are then addressed, as well as the sense/reference distinction. In the second section, I turn to consider [logical not] and argue that we cannot escape negative facts, and facts conjoining and disjoining negative facts with positive facts. I then give [logical not] a distinctive role, one that contrasts with & and v. in the third section, I say what logic is not. We should not take logic to be essentially about the mind, or language, or exclusively about an abstract realm, or about reasoning, inferential roles, truth, truth-tables, topic-neutrality or form. Key words: realism; conjunction; disjunction; negation; "Alexander"s principle