Although the suggestion of a dialogue with Communism has been looked upon by some Catholics as hopeless and unproductive, while being openly criticized by others, the possibility of such a dialogue is at least implied by Pope John XXIII in Pacem in Terris.
'It must be borne in mind, furthermore, that neither can false philosophical teachings regarding the nature, origin, and destiny of the universe and of man be identified with historical movements that have economic, social, cultural or political ends, not even when these movements have originated from these teachings and have drawn and still draw inspiration therefrom.
This is so because the teachings, once they are drawn up and defined, remain always the same, while the movements, working in constantly evolving historical situations, cannot but be influenced by these latter and cannot avoid, therefore, being subject to changes, even of a profound nature . . .
It can happen, then, that meetings for the attainment of some practical end, which formerly were deemed inopportune and unproductive, might now or in the future be considered opportune and useful.’
Applying this insight of Pope John XXIII, a distinction should be made between the theory of Communism and the Communist movement in history. Certainly Communism is based on a false philosophy of the nature, origin and destiny of man. The historical movement of Communism originated from those false teachings and still draws upon them for inspiration. Further, these teachings, as permanently recorded and defined, remain the same.