Indeed, it is compatible with Catholicism to admit that it
feels incomplete to take just one species, because feelings and reality are not necessarily going to line up. So a faithful Catholic might say that it does indeed
feel incomplete, as long as he admits that this is just a feeling, not a reality.
Now the
symbolism is indeed “fuller” by receiving under both kinds. While the Host and the Cup each truly
contain both the Body and Blood, the Host clearly better
symbolizes the Real Presence of the Body it truly is, and the Cup clearly better
symbolizes the Real Presence of the Blood it truly contains. For this reason, many theologians would indeed agree that it is a fuller symbol if one receives both kinds.
The reason, in fact, that for a long time the Liturgy called for only giving the Faithful One Kind was, if I recall correctly, because of excessive persistence of a heresy that said that the Host only contained the Body and the Cup only contained the Blood. In order to stamp out this heresy, if I understand correctly, the Tridentine Mass only allowed the lay Faithful to receive the Host, so as to better emphasize the point that each species contained both the Body
and Blood. This was an extreme circumstance, and the Church probably felt that it was more important to protect an orthodox understanding of our Faith, even if it meant the symbolism mentioned above wasn’t quite as “full.” Right belief outweighs the importance of symbolism. Of course, even then, it’s important to note that both kinds were
consecrated, and even taken by the Priest, just not received by the Lay Faithful.
As for reasons a person might willingly not take both Species, there might be any number of reasons. The person might be ill and not want to spread it. Or there might be an illness going
around. Or the person may have celiac disease and not be able to have gluten, as would be found in the scientific properties of the Host. Or a person may be an alcoholic, and need only a sip of what tastes and behaves like wine to feel tempted.
You’re welcome.
As for the Orthodox Church’s practice, it’s hard to say. They believe in the Real Presence, just as we do, and in my previous post I covered how believing that each species contains both the Body and Blood can be logically inferred from that belief. However, that’s not necessarily to say that the Orthodox have inferred that, yet. Just as it’s possible that, at some point in the Catholic Church’s history, this doctrine had not yet developed in a concrete way (even though it can be seen as an implied necessity just from believing in the Real Presence), so too might it be true that the Orthodox haven’t developed this doctrine in a concrete way down to this very day. I don’t
know for sure what they believe about it, and you’d have to ask a member of the Orthodox Church, but it’s possible that, as I say, they simply haven’t made this same development.
Alternatively, it’s possible that the Orthodox
do believe that both Body and Blood are present in each individual species, just as we do (again, I don’t know what they believe, exactly) but are simply more strict about enforcing the “full symbolism” mentioned above by requiring that both kinds be received
despite that each species contained both Body and Blood. In that case, from a Catholic understanding (even if not an Eastern Orthodox understanding) a practice like this would be more of a disciplinary measure than an unchangeable doctrinal one, in the same way that the Tridentine Mass’s lack of reception of the Cup for the Faithful was a disciplinary measure and not an unchangeable doctrinal one.
I hope this makes sense.
Blessings in Christ,
KindredSoul