> "[The Marcionites] were perhaps the most dangerous foe Christianity has ever known"
Catholic encyclopedia on "Marcionites": https://www.newadvent.org/cathen/09645c.htm
Stumbled upon this from people posting about other heresies and was thinking more reading about heresies might be helpful for people to understand and avoid error
Remember, in every conflict there are two sides. The Catholic Encyclopedia only gives the Catholic perspective. The Marcionite version is quite different and sheds a lot of light on why they believe the way they do. In particular, it has everything to do with rejecting jews and refusing to accept infiltration of jewish beliefs into the Christian faith.
if this is your motivation, users like crusaderpepe are frequently posting against "Jewish errors" from a Catholic perspective; hence you could be Catholic and oppose certain Jewish errors
> The Catholic Encyclopedia only gives the Catholic perspective.
Naturally, although I can see why people might independently side with Catholicism, as Marcionism proposes:
Two different gods (one of Old Testament, one of New); the teaching Jesus only appeared to be human (docetism); matter is inherently evil contrary to Genesis 1:31 that all that God made was "good" (like Manicheanism); Gnostic tendencies of salvation through secret knowledge, rather than through faith and works.
But there are so many different modern and historical interpretations of this stuff that Christianity necessarily has some agnosticism baked into it for anyone who engages seriously with the whole library. Trying to figure out the single, narrow, exclusively "correct" school of theology is like going on fanfiction.net, reading the entire body of work for a popular IP, and then having to independently decide which author has "the canon" interpretation of the source material. All with you never having accessed that source material yourself nor having any way to do so.