Online research in philosophy

As is well known, Carnap's conventionalism was a rejection to Kant's view ofmathematics and was fully developed in his Logische Syntax der Sprache.The purpose of this article is to step back to Der Logische Aufbau der Weltto show that the Logical Syntax of Language is an attempt to solve difficultiesfound in the earlier construction. I first clarify the notion of conventionalism, whichplays a central role in the application of mathematics to the reconstruction of empiricalknowledge. By not strictly distinguishing between the intuitive notion and thetopological concept of dimension, Carnap is led to a construction which is highlyquestionable. To illustrate the constructive method developed in the Aufbauand some of its inherent difficulties, I consider the computational aspects of theconstruction of phenomenological space via the mathematical concept of dimension.Contrary to Carnap's conventionalism, a dual nature of mathematical statements isbrought into existence by his logical reconstruction. So, if Carnap wants to retainhis mathematics as devoid of content, he must make a clear-cut distinction betweenanalytic and synthetic statements. Thus the natural follow-up to the Aufbau isthe Logical Syntax of Language.

I offer a new interpretation of Aristotle's philosophy of geometry, which he presents in greatest detail in Metaphysics M 3. On my interpretation, Aristotle holds that the points, lines, planes, and solids of geometry belong to the sensible realm, but not in a straightforward way. Rather, by considering Aristotle's second attempt to solve Zeno's Runner Paradox in Book VIII of the Physics , I explain how such objects exist in the sensibles in a special way. I conclude by considering the passages that lead Jonathan Lear to his fictionalist reading of Met . M3,1 and I argue that Aristotle is here describing useful heuristics for the teaching of geometry; he is not pronouncing on the meaning of mathematical talk.

We take another look at Reichenbach’s 1920 conversion to conventionalism, with a special eye to the background of his ‘conventionality of distant simultaneity’ thesis. We argue that elements of Reichenbach earlier neo-Kantianism can still be discerned in his later work and, related to this, that his conventionalism should be seen as situated at the level of global theory choice. This is contrary to many of Reichenbach’s own statements, in which he declares that his conventionalism is a consequence of the arbitrariness of coordinative definitions.

Geometry was a main source of inspiration for Carnap’s conventionalism. Taking Poincaré as his witness Carnap asserted in his dissertation Der Raum (Carnap 1922) that the metrical structure of space is conventional while the underlying topological structure describes "objective" facts. With only minor modifications he stuck to this account throughout his life. The aim of this paper is to disprove Carnap's contention by invoking some classical theorems of differential topology. By this means his metrical conventionalism turns out to be indefensible for mathematical reasons. This implies that the relation between to-pology and geometry cannot be conceptualized as analogous to the relation between the meaning of a proposition and its expression in some language as logical empiricists used to say.

Hans Reichenbach's so-called geometrical conventionalism is often taken as an example of a positivistic philosophy of science, based on a verificationist theory of meaning. By contrast, we shall argue that this view rests on a misinterpretation of Reichenbach's major work in this area, the Philosophy of Space and Time (1928). The conception of equivalent descriptions, which lies at the heart of Reichenbach's conventionalism, should be seen as an attempt to refute Poincaré's geometrical relativism. Based upon an examination of the reasons Reichenbach gives for the cognitive equivalence of geometrical descriptions, the paper argues that his conventionalism is a specific form of scientific realism. At the same time we shall argue against those interpretations which lead to a trivialization of Reichenbach's conventionalism or deny it entirely.

Within the epistemology of the sciences, conventionalism has been the subject of regular criticism for over six decades. Critics such as W. V. Quine and Morton White, and more recently Nathan Salmon (1992), and Paul Boghossian (1996), have attacked even the most basic tenet of conventionalism, namely its claim that the truth of certain statements is fixed not by stipulation-independent facts, but by the conventions governing the meaning of those statements and their constituents.

The logical positivists adopted Poincare's doctrine of the conventionality of geometry and made it a key part of their philosophical interpretation of relativity theory. I argue, however, that the positivists deeply misunderstood Poincare's doctrine. For Poincare's own conception was based on the group-theoretical picture of geometry expressed in the Helmholtz-Lie solution of the space problem, and also on a hierarchical picture of the sciences according to which geometry must be presupposed be any properly physical theory. But both of this pictures are entirely incompatible with the radically new conception of space and geometry articulated in the general theory of relativity. The logical positivists's attempt to combine Poincare's conventionalism with Einstein's new theory was therefore, in the end, simply incoherent. Underlying this problem, moreover, was a fundamental philosophical difference between Poincare's and the positivists concerning the status of synthetic a priori truths.