Abstract
Balancing implies a comparison among goods, values, principles and rights that cannot be ranked on a single scale of measurement, ie there is no unequivocal measuring unit applicable to all of them. In such situations, it is common to state that one has to compare incommensurable things. Indeed, this issue has been mentioned by several authors as a strong reason in favour of abandoning balancing (and proportionality) as a rational form of judicial argumentation and decision-making. My article aims at arguing that this objection is based on fallacious assumptions concerning the relations among three concepts: incommensurability, incomparability and balancing. Initially, what is at stake is the analysis of the connection between comparing values (or principles) and commensurability. The results of this initial analysis were then used to provide greater analytical strength to the specific debate on balancing and comparing rights in order to show that incommensurability does not imply incomparability and that rational decisions are possible even when incommensurable values are at stake. Since balancing (and proportionality) implies comparisons, and since constitutional principles are doubtlessly incommensurable (for there is no common metric to measure them), arguing for the comparability of incommensurable principles is an unavoidable step if one aims at demonstrating that balancing may be a rational procedure after all.