As a Catholic I am bemused by the number of times I see this or even much higher figures than 40,000 denominations thrown in to bolster an argument about why sola scriptura is wrong. I think it unfair in debate if it can’t be substantiated.
I want to see a list of these 40,000 denominations. I personally know of perhaps 20 or 30.
Advent Christian Church
Adventists
African Methodist Episcopal Church
African Methodist Episcopal Zion Church
Agapemone
Aglipayans
Amana Church Society
Amish Church
Anabaptists
Anglican Communion
Anglo-Catholic movement
Armenian Church
Arminianism
Assemblies of God
Baptists
Behmenites
Bereans
Beroeans
Bible Christians
Bible societies
Brethren in Christ
Brethren
Broad Church
Brotherhood of the New Life
Brownists
Burghers
Calixtines
Calvinism
Calvinistic Methodist Church
Camisards
Campbellites
Catholic Apostolic Church
Christadelphians
Christian Catholic Church
Christian Church (Disciples of Christ)
Christian Endeavor
Christian Reformed Church
Christian Science
Christian socialism
Christians
Church of Christ, Scientist
Church of England
Church of the Brethren
Church of the Nazarene
Churches of Christ
Churches of God, General Conference
Community of Christ
Confessing Church
Congregationalism
Covenanters
Cumberland Presbyterian Church
Diggers
Disciples of Christ
dissenters
Doukhobors
Dukhobors
Dunkards
Dunkers
Dutch Reformed Church
England, Church of
Episcopal Church, Reformed
Episcopal Church
Ethical Culture movement
Evangelical Alliance
Evangelical and Reformed Church
Evangelical Church
Evangelical United Brethren Church
Familists
Fifth Monarchy Men
Foursquare Gospel, International Church of the
Free Church of Scotland
Freewill Baptist Church
Friends, Religious Society of
fundamentalism
German Baptist Brethren
German Catholics
German Reformed Church
Gideons
Glassites
Harmony Society
High Church
Huguenots
Hussites
Hutterian Brethren
Illuminati
Independents
Ireland, Church of
Jehovah’s Witnesses
Latter-day Saints, Church of Jesus Christ of
Latter Day Saints, Reorganized Church of Jesus Christ of
Levelers
Lollardry
Low Church
Lutheranism
Mennonites
Methodism
Moral Re-Armament
Moravian Church
Mormons
National Council of the Churches of Christ in the United States of America
New Church
New Jerusalem, Church of the
New Thought
nonconformists
Oxford Group
Oxford movement
Peculiar People
Pentecostalism
People’s Temple
Pietism
Plymouth Brethren
Presbyterianism
Protestant Episcopal Church
Protestantism
Puritanism
Quakers
quietism
Racovian Catechism
Ranters
Reformation
Reformed Church in America
Reformed Church in the United States
Reformed churches
Reformed Episcopal Church
Reformed Presbyterianism
Remonstrants
Renewed Church of the Brethren
River Brethren
Sabbatarians
Salvation Army
Scotland, Church of
Scotland, Free Church of
Second Adventists
separatists
Seventh-day Adventists
Seventh-Day Baptists
Shakers
Social Gospel
Socinianism
Solemn League and Covenant
South India, Church of
Southern Baptist Church
Taborites
Tractarian movement
Tunkers
Unitarian Universalist Association
Unitarianism
Unitas Fratrum
United Brethren in Christ
United Church of Canada
United Church of Christ
United Methodist Church
United Presbyterian Church
United Zion Church
Unity
Universalist Church of America
Utraquists
Vaudois
Waldenses
World Council of Churches
Yorker Brethren
Zionites
This is a partial list… once you get past these, look at all the independant churchs, the non-demoninationals, etc. I don’t know that there is 40,000 but there are certainly thousands and growing.