This article shows, in the first place, that the two main arguments that have been used to distinguish social rights from liberal rights are based on two different concepts of subjective right and, in second place, that the two main lines of argument through which the equalization of these two categories of fundamental rights have been procured, are constructed from a critique of the two concepts of subjective right that serve as a basis for their distinction. That done, these lines of argument have been analyzed critically in order to show that, although they are able to reduce the gap between social and liberal rights, they are not able to fulfil the intended aim.