There are a lot of visible ways that the two Churches are the same: vestments, structure of worship, etc... There are also a lot of visible ways that they are different - women priests to name just one. Those similarities and differences all stem from a few fundamentals.
Let's start with:
How are the Episcopal and Roman Catholic Churches the same?
There are three main similarities between the Episcopal and Roman Catholic Churches:
- Our worship services (especially the Eucharist) follow the ancient pattern of worship that was established in the early Church. We have the first half of the service, the Liturgy of the Word - where we have an opening prayer, hear portions of Scripture read, have a sermon, recite the Nicene Creed and join in prayers for the Church & the world. Then the second half of the service is the Liturgy of the Table - where we bless bread and wine using the words of Jesus at the Last Supper, break the bread and share communion.
- We have three-fold orders of ordained ministry. We have deacons, who are ordained to bring the needs of the world to the Church and help the Church connect with the world. We have priests (all of whom were ordained deacons first) who teach the faith, preside over the sacraments and guide congregations. We have bishops (all of whom were ordained deacon & priest first) who guard the faith and oversee the ministry of Dioceses.
- Our churches have Dioceses (made up of congregations in a geographic region), which are the basic administrative unit of the church. Geographic groups of Dioceses are formed into provinces and national churches.
How are the Episcopal and Roman Catholic Churches different?
There are four main differences between the Episcopal and the Roman Catholic Churches:
Theology: The Episcopal Church is a Protestant Church in terms of theology. What that means is that in the Roman Catholic Church the magisterium (or teaching authority) of the church tells Roman Catholics what they should believe. In Protestant theology the role of the Church is to provide boundaries for the believer, within those boundaries, the individual decides (in relationship with God) what they believe.
For Example: The Episcopal Church teaches that God is the creator of the heavens and the earth. Individual Episcopalians can believe that God set off the Big Bang; that God influenced evolution; that God created the world in seven 24-hour days and a wide variety of other ways that God was the creator of the heavens & the earth - all of which are acceptable.
Eucharist: The Roman Catholic Church teaches that what happens at Eucharist is transubstantiation - that the bread and the wine literally become the Body & Blood of Christ while maintaining the outward appearance of bread and wine.
The Episcopal Church teaches the doctrine of the Real Presence - that is that the Body and Blood of Christ are really present in the bread and wine. How that happens; transubstantiation, consubstantiation, in some other way is something the Episcopal Church doesn't require specific belief about.
The Role of the Laity: The Episcopal Church believes that the laity have a specific role in the governance of the Church. Episcopal Churches have vestries that are elected by the members of the Church. Those vestry members are responsible for the budget of the congregation and for overseeing the programs of the church. The rector is a part of the vestry and has some specific rights and duties, but the church in governed in collaboration between the rector & the vestry. When a congregation calls a new rector it is the vestry who votes on who that should be. The Bishop has to approve the call, but it is the vestry who makes the decision.
The same thing happens at the Diocesan level. Each congregation sends lay representatives to Diocesan Convention and those representatives, as well as the priests and deacons in that Diocese, get to make decisions about the life of the Diocese, including electing their bishop.
Authority - in the Episcopal Church the majority of the authority sits with the Diocesan Convention and the Diocesan Bishop.
The General Convention of the Episcopal Church (which is made up of a House of Bishops and a House of Deputies of elected representatives, lay and clergy, from each Diocese) makes decisions about our Book of Common Prayer & the National Canons, but each Diocese decides how to implement those.
The House of Bishop elects a Presiding Bishop (currently The Most Rev. Michael Curry) that election is approved by the House of Deputies. The Presiding Bishop doesn't have any authority to tell Diocesan Bishops what they have to do. He (or she) even needs the permission of the Diocesan Bishop to preside at Confirmations or Ordinations within the boundaries of a particular Diocese.
While the Episcopal Church is part of the Anglican Communion, a coalition 38 Churches that are in communion with the Archbishop of Canterbury including the Episcopal Church, The Church of England, the Anglican Church of Canada and the Anglican Church of Australia among others, no one outside of the Episcopal Church (including the Archbishop of Canterbury) has any authority over how the Episcopal Church governs ourselves. What this means is that each Church in the Anglican Communion makes its own decisions about our Books of Common Prayer, ordination, structure, budget etc...
For Example: The Episcopal Church ordained women to the priesthood in 1976 and the first woman as Bishop in 1988. The Church of England did not ordain women to the priesthood until the 1990's and didn't ordain women as Bishops until a few years ago. The Anglican Church of Somalia still does not ordain women to the priesthood.
The Episcopal Church does not have an equivalent to the Pope, someone who has authority over the whole church all over the world and everyone who holds any position of authority in the Episcopal Church has been elected to that position by groups who include lay people as well as priests and bishops.
Obviously, this is only a basic description of the difference between the two Churches. If you have questions or want to know more, please email me at firstname.lastname@example.org