The article entitled, “Jevons on measurement: A comment” (Mosselmans [1998]), betrays a lack of comprehension of the Jevonsonian process of productive abstraction of numbers. This misapprehension is clearly apparent when B. Mosselmans wrongly confuses units for numbers. This especially furthers the circumvention of the Jevonsonian idea according to which the world is ruled by numbers.

Utility is not a measurable magnitude, yet it is impossible to feature it in the theory of exchange? Jevons responds by the negative. In his view, it does exist a general theory concerning the mathematical expression of magnitude that is not measurable. This assertion is found in the Theory of Political Economy and in The Principle of Science.

There is an entire branch of industrial location analysis in economics and operational research that refers back to Weber. In this paper I show that the model he developed had already been proposed by W. Launhardt in 1882 as a generalization of a route planning method presented in 1872. It contained all the technical aspects of Weber’s model. That does not mean Weber should be forgotten though, as his contribution involves far more than the simple presentation of the model. In terms of method, he defends and uses the hypothetical-deductive method. As for the content, he attempts to understand the formation of concentrations of economic activities and population, which leads to an interesting analysis of agglomeration economies.

The paper discusses the relation between the justly famous Hotelling’s [1929] paper on stability in competition and the corresponding passages of the often ignored Launhardt’s [1885] book, devoted to mathematical economics. Launhardt is sometimes credited for the anticipation of Hotelling’s spatial model and analysis of oligopolistic competition with product differentiation. The paper argues that Launhardt’s model is in fact significantly more general, in particular in introducing vertical along with horizontal differentiation, and that his analysis of strategic competition is correspondingly finer and more complete. Thus, the earlier author does not appear to be a forerunner of the later, rather the later a successor of the earlier. However, Hotelling did (objectively) innovate, in a significant way, by endogenizing locations as strategic variables, and principally by developing the concept of an abstract characteristics space, which transcends the geographical space.

The interest shown in territorialized productive organizations does not simply account for a geographical phenomenon but above all highlights the territorial dimension of development and innovation processes. In the wake of the work done on Italian industrial districts, numerous studies have been conducted that have made it possible to identify similar forms of localized productive organizations. The aim of the present paper is to attempt a synthesis of the way in which these territorialized productive organizations work. To do so, we shall select two concepts: the localized production system and the milieu. The fundamental question is then to identify which logic influences the way a localized production system works: the milieu-actuated territorial logic or the functional logic, which corresponds to industrial organization of an hierarchical nature.