I am an Orthodox Christian. I believe that the Roman Catholic Church and the Eastern Orthodox Church are both Apostolic Churches, albeit, not in full communion. I converted to EO from Calvinism after being raised Pentecostal. I don’t believe that any “positive” and “non-polemical” teaching of the EOC contradicts or requires me to disbelieve in RCC doctrines such as the Immaculate Conception, Purgatory, or Indulgences. I am assuming that I am considered a catholic Christian with access to salvific sacraments from the Roman Catholic pov (re: Vatican II’s Decree on Ecumenism, Orientale Lumen).
My question is, can I gain plenary indulgences for souls in purgatory while being a member of the Eastern Orthodox Church? I try to pray the Rosary every day, and there is a chapel at the local cathedral a few blocks from work, so I could easily fulfill the conditions for a plenary indulgence three or four times per week.
The Catechism of the Catholic Church refers to the “Christian faithful” as the subjects of indulgences.
The Church is the dispenser of indulgences and so it would be logically assumed that those faithful united in full communion with the Church are those Christians who are able to obtain the indulgences which the Church so generously dispenses.
However, the Catechism, and Paul VI’s Indulgentiarum doctrina, only speak of the Christian faithful, not of Catholics. The Christian faithful must be properly disposed, free from any ecclesiastical penalties, and having received the sacraments of Penance and the Eucharist within the prescribed times for the indulgence.
Some might consider an Eastern Orthodox person to be in a state of schism, but, canonically, the culpability for schism is only incurred by those who, having once been united to the Church, have separated themselves from it. One who is born and raised outside the Church, though he be in de facto schism from the Church, is not imputable for the sin of schism (though he should be urgently encouraged to return to the fullness of the Church).
Therefore, it seems that it might be possible for an Orthodox Christian, who has never been Catholic, to obtain an indulgence. It certainly does no harm to try!
Having said that, if you believe what the Catholic Church teaches regarding Purgatory, Indulgences, the Immaculate Conception (issues that are not necessarily at odds with official Orthodox teaching but which are certainly taught more clearly by the Catholic Church), why not advance the issue of true ecumenism and become Catholic?
Then, most certainly, there would be no doubt whatsoever about your ability to gain indulgences.