These days "orthodoxy" has a lot of different varieties, and what counts as "heresy" depends on where you stand. What is orthodoxy to me (that baptism saves you by the resurrection of Christ) is heresy on some neighboring blogs, and other examples are so easy to come by that there's no need to bother.
Here I just wanted to name some of the "heresies" with which I find myself in sympathy, precisely because I think they may have very well been in-bounds rather than out -- or in some cases, not even a question on the table -- in the apostolic church.
- Annihilation of the condemned - I am not convinced that the annihilation of the condemned is true; it's just that I am not convinced that the faith once given included eternity in hell for the damned. I am aware of a passage which makes it sound as if hell is eternal; I am also aware of several more where the plainest reading is the annihilation of the lost. On the basis of such passages, I think that annihilation should be "in-bounds" as far as beliefs go, and not considered heretical.
- Single procession - the earlier versions of the Nicene Creed confessed that the Holy Spirit "proceeds from the Father" which is a quote from Christ. The phrase "and the Son" was a late addition to the Creed, and one that has never been universally recognized the way the original creed was recognized. For this reason, I think that belief in single procession should be in-bounds, rather than heretical, and reciting the Creed without the "filioque" ("and the Son") clause should be an acceptable variation.
- Faith as trust - Jesus once compared the kingdom of heaven to a man who had two sons and sent them out to work. One said "Yes sir" but ditched when it came time to work. The other said "Take a hike" but actually did what he was asked. I have to ask myself whether this applies to the nominal atheist -- the one who keeps it in his pocket that "If God really is good, he'll have some compassion on us and judge us with decency and mercy." and lives his life according to this faith. I think that an atheist who can say that has a better confession of faith than a Christian who confesses all the points of an intellectual creed but proclaims "God is a hard man, who reaps what he did not sow," who preaches the injustice of God rather than his goodness.
- The three hypostases and the one essence or substance - The language in which we describe the Trinity is mainly foreign to the apostolic church. I am fully on board with the fact that the early, apostolic church -- and Christ himself -- and the Old Testament, while we're on the subject -- all speak as if God, and His Word, and His Spirit are all inseparably bound up in what it means to be God in relation to this created world. That is not quite the same as thinking that the philosophical explanations hammered out in the 200's, 300's and 400's (and later) actually do justice to what it means to know God in relation to this world. I think those philosophical explanations should be in-bounds, no doubt, but not to the extent that they limit the discussion, or are seen as the ultimate word on the subject, or preclude exploring fuller explanations of the essential mystery of God.
I'm curious, does anyone else have favorite "heresies"? And if so, why?