Philosophical anthropology claims that every human being necessarily operates in specific communities. These communities must also be based on certain ethical principles. One of the principles forming this ethical foundation is the principle of social justice. The Polish Constitution of 1997 does not contain any legal definition of this principle and the doctrine has problems with defining it as well. In this connection, the Catholic Social Teaching, which combines the principle of social justice with human dignity, the common good, equality and solidarity, can be an important interpretative support.