With this work I want to analyze the epistemological difficulties related to the use, by the Constitutional Court, of principles equality, human dignity, reasonableness, proportionality as interpretive parameters and basis for their decisions. This modus operandi is open to some difficulties, not least those arising from the difficulty of defining conceptually some of them and from the large margin of discretion related to the introduction of the principles as autonomous sources of decision. In particular we want to focus attention on the interest and on the sensitivity that the constitutional judges – especially the Italian – have expressed to the principle of human dignity, declined as a right to have a free and dignified life. The challenge of this work is also to highlight the difficulties related to the legal definition of human dignity. The compliance with this principle and its invocation as a source of decision can be considered a rule of interpretation useful if not necessary to define the so called “hard cases” in which the respect of economic and financial needs is at odds with the need to protect the core of social rights provided in the Constitution With this work I want to analyze the epistemological difficulties related to the use, by the Constitutional Court, of principles as interpretive parameters used as a basis for their decisions. In recent years in Europe there has been a situation of economic crisis that can be defined as “systemic” and not merely “cyclical”, in which social rights‟ protection, more than other rights‟ protection, seems to be in danger and in which the traditional interpretative tools used by the constitutional judges are undermined by the new challenges posed by the evolution of the society. Consequently, in Europe, some Constitutional Courts have tried to propose solutions that concretely balance the economic and financial needs of the states often negatively affected by the parameters set at the European level with the protection of the “core” of social rights1. In this context, some constitutional judges, such as the Italian, but also Spanish and Portuguese ones, have structured their own decisions following as fil rouge a reasoning based on “fundamental principles”, more or less sharp according to the cases