28 If prayer is the "soul" of ecumenical renewal and of the yearning for unity, it is the basis and support for everything the Council defines as "dialogue". This definition is certainly not unrelated to today's personalist way of thinking . The capacity for "dialogue" is rooted in the nature of the person and his dignity. As seen by philosophy, this approach is linked to the Christian truth concerning man as expressed by the Council: man is in fact "the only creature on earth which God willed for itself"; thus he cannot "fully find himself except through a sincere gift of himself". Dialogue is an indispensable step along the path towards human self-realization , the self-realization both of each individual and of every human community . Although the concept of "dialogue" might appear to give priority to the cognitive dimension ( dia-logos ), all dialogue implies a global, existential dimension. It involves the human subject in his or her entirety; dialogue between communities involves in a particular way the subjectivity of each. This truth about dialogue, so profoundly expressed by Pope Paul VI in his Encyclical Ecclesiam Suam , was also taken up by the Council in its teaching and ecumenical activity. Dialogue is not simply an exchange of ideas. In some way it is always an "exchange of gifts".
Source: Ut Unum Sint (Vatican.va)