This paper shows briefly the dual transition from the Liberal State to the Welfare State, as well as from the Legal State to the Constitutional State. It explains some of the causes, elements and consequences of the constitutional State and how this form of State can be characterized, as well as some of the difficulties that this view implies. It also attempts to show how this transition is reflected in the conception of human dignity hosted by the Colombian Constitutional Court, a perspective summarized at the decision T-881 2002. Finally, this article lays the basis from which the ideas of Constitutional State, human dignity and free development of personality may be useful in the analysis of relations between private parties, including contractual relations. These will be subject of a posterior article.