In his encyclical Quam Singulari (August 1910), the remarkable Pope Pius X comes very close to endorsing paedocommunion. He quotes the gospel passages about Jesus welcoming children, and observes that, following the example of Jesus, the church “took care even from the beginning to bring the little ones to Christ through Eucharistic Communion, which was administered even to nursing infants. This, as was prescribed in almost all ancient Ritual books, was done at Baptism until the thirteenth century, and this custom prevailed in some places even later. It is still found in the Greek and Oriental Churches. But to remove the danger that infants might eject the Consecrated Host, the custom obtained from the beginning of administering the Eucharist to them under the species of wine only. Infants, however, not only at the time of Baptism, but also frequently thereafter were admitted to the sacred repast. In some churches it was the custom to give the Eucharist to the children immediately after the clergy; in others, the small fragments which remained after the Communion of the adults were given to the children.”

The practice died out in the West, and the requirement that anyone coming to the Eucharist must have the “use of reason” was stated at the Fourth Lateran Council in 1215 and confirmed by Trent, though without, Pius said, any hint of condemnation of the earlier practice. But, Pius continues, there has been widespread confusion about the definition of “use of reason” and “age of discretion,” confusions that have produced “not a few errors and deplorable abuses”:

“There were some who maintained that one age of discretion must be assigned to reception of the Sacrament of Penance and another to the Holy Eucharist. They held that for Confession the age of discretion is reached when one can distinguish right from wrong, hence can commit sin; for Holy Eucharist, however, a greater age is required in which a full knowledge of matters of faith and a better preparation of the soul can be had. As a consequence, owing to various local customs and opinions, the age determined for the reception of First Communion was placed at ten years or twelve, and in places fourteen years or even more were required; and until that age children and youth were prohibited from Eucharistic Communion.” Pius insists that Lateran, Trent, and all church opinion since has viewed the requirements for Eucharist and Confession as the same. There isn’t any gap in the requirements or the timing.

As a result of these practices, “children in their innocence were forced away from the embrace of Christ and deprived of the food of their interior life; and from this it also happened that in their youth, destitute of this strong help, surrounded by so many temptations, they lost their innocence and fell into vicious habits even before tasting of the Sacred Mysteries.” He also condemned “the practice in certain places which prohibits children who have not yet made their First Communion from being fortified by the Holy Viaticum, even when they are in imminent danger of death; and thus, when they die they are buried with the rites due to infants and are deprived of the prayers of the Church.”

Extraordinary preparation for Eucharist are not necessary, as the earlier example of the church makes plain: “the fact that in ancient times the remaining particles of the Sacred Species were even given to nursing infants seems to indicate that no extraordinary preparation should now be demanded of children who are in the happy state of innocence and purity of soul, and who, amidst so many dangers and seductions of the present time have a special need of this heavenly food.” After surveying some theologians and earlier papal opinions, he concludes “the age of discretion for receiving Holy Communion is that at which the child knows the difference between the Eucharistic Bread and ordinary, material bread, and can therefore approach the altar with proper devotion. Perfect knowledge of the things of faith, therefore, is not required, for an elementary knowledge suffices-some knowledge ( aliqua cognitio ); similarly full use of reason is not required, for a certain beginning of the use of reason, that is, some use of reason ( aliqualis usus rationis ) suffices.”

For those looking for a specific age, Pius suggests that children learn to reason in this sense around the age of 7, and “from that time on begins the obligation of fulfilling the precept of both Confession and Communion” and their participation should be regular: “Those who have charge of the children should zealously see to it that after their First Communion these children frequently approach the Holy Table, even daily if possible, as Jesus Christ and Mother Church desire, and let this be done with a devotion becoming their age.”

Pius’s argument from the innocence and purity of children isn’t convincing. It’s rather surprising that he doesn’t root the argument in baptism. But the overall direction of the argument is sound. It’s worth remarking that it has taken Protestant churches the better part of a century to catch up.