“The Father is that which the Son is, the Son that which the Father is, the Father and the Son that which the Holy Spirit is, i.e., by nature one God.”84 In the words of the Fourth Lateran Council (1215): “Each of the persons is that supreme reality, viz., the divine substance, essence or nature.
3) You insist on using the modern, everyday definition of the word “person.” A skilled reader knows he must use the definition of the writer(s) of the relevant document(s). The official language of the Catholic Church is currently Latin. Therefore, the actual word used in the Catechism is “persona” which means face or mask. The lingua Franca used to be Greek, so when the Trinity was first formulated, the word used was “prosopon” which also means face or theatrical mask.