A helpful distinction needs to be made here. Being a saint isn’t reserved exclusively to those whom the Church has declared such. Rather, a saint is anyone who has made it to heaven and now beholds the presence of God. One need not be declared by the Church to receive this honor: only God needs to declare it. So, yes, it’s all together likely that there are saints in heaven who weren’t Catholic.
But there remains the question of whether the Church could canonize a non-Catholic individual.
It would seem that bestowing such an honor would help foster greater unity between the Catholic Church and other churches and faiths. By our acceptance and recognition of virtuous men and women in other traditions, we could turn the page on a seemingly darker past of condemnation and be working toward the day where we can all unite in worship.
While this is a seemingly noble goal and a gesture toward it, the Church would still not likely take it for two reasons.
First, the process to canonize someone affirms a belief in the authority of the Church. To canonize someone, the Church first requires a group to contact the local bishop to consider pursuing a cause. If there is a desire to do so, there must be a willingness to investigate thoroughly the life of the person being considered to be a saint. Following this investigation, the life of the person is put before the Congregation for the Causes of Saints in a sort of trial to see if the person has a basic degree of sanctity and holiness in their life.
In just the first three steps, we see an acknowledgement of the authority of the bishop, the authority of Church officials to investigate, and the authority of the Church to judge.
Non-Catholics would likely not welcome such a process, even to celebrate the life of someone who lived a saintly life. This process would force them to acknowledge an authority in the Church they do not recognize fundamentally.
Second, canonizing a saint has been reserved to Catholics as an encouragement to us. It shows us that our faith does produce great men and women of sanctity and holiness. While there can be great virtue and holiness in people outside of the Church, the list of canonized saints is of special meaning to us as Catholics. These men and women shared this same faith I do and faced the same trials and struggles I do and yet they remained faithful to Christ and the Church and even became holier for it. How did they do that? That is our encouragement to get to know these saints better.
Father Mayo is pastor of Holy Rosary Parish in Warrenton.