Title II of the Federal Constitution contains a catalog of rights and guarantees that considers fundamental. It would not be possible for the Constituent to foresee all those that are part of this category, which is why, currently, it recognizes the so-called material fundamental rights and guarantees, or sparse materially fundamental rights and guarantees, which, although they possess the attribute of essentiality, are found outside the constitutional catalog. There is no significant divergence on the existence, or not, of fundamental rights and guarantees outside the Constitution, since the Constitution by itself provides for this (art. 5, §2). However, there is still a problem about the definition of fundamentality, since there are no constitutional parameters for this. In view of this, some hermeneutic tools stand out as being adequate to determine whether a certain right or guarantee, foreseen outside the constitutional catalog, is in fact fundamental.