Many have said that the Pew study reflects a catechetical failure. I fear the opposite: it reflects a certain kind of catechetical success. It is the result of an unwritten catechesis that American Catholics have been slowly learning. Through a deracinated, spiritualistic, and emotivistic treatment of the Eucharist, many Catholics have learned their faith from a generation of pastors who stripped the altars, razed the bastions of reverence around the Lord in the sacrament, and who generally treated the Most Holy Eucharist itself as something to be passed out like a leaflet rather than received in awe, as people prostrate before the fire of divinity. Far too many have received this kind of unwritten catechesis.
Chad Pecknold writes much more here.
I have never understood what Aquinas meant by susbstance. And I have been taught that ‘symbol’ is used by the church to mean the real thing, cf the Apostles’ Creed or symbolum apostolorum. I found this, by Alan Griffith on ‘Pray Tell’ :
“Questions as to what we mean by ‘substance’ and ‘identity’ – and what Saint Thomas meant too – are both abstruse and fundamental. However, ‘substance’ to most people means the physical constituency of something, its chemical or molecular content. If people are said no longer to believe in a change of ‘substance’ in the Eucharistic species, that would be hardly surprising. It means that people might actually be thinking orthodox thoughts ‘secundum quid.’”
The Pew study did not base the major finding on anyone ‘s knowledge or use of the word “substance.” The question was whether they personally believe that “during Catholic Mass, the bread and wine actually become the body and blood of Jesus.” Only 31% of Catholics believe that core teaching, put into the simplest terms.