Humanist ideas should give the option to syncretise religions, like the Dhimmi

[MachopPower69]

I thought about it because you are literally giving religious minorities more equality yet you can still convert lands when your RU is 100%+. Having Humanist ideas give a unique mechanic like the dhimmi should be a thing. If you have a large empire and most of your realm isn't of your religion, the mechanic can give bonuses such as what the Dhimmi does. Another thing is that it could give you a secondary religion like what Tengri does. England was full of Catholics and Protestants, and Lithuania was divided between Orthodoxy and Catholicism. Having a mechanic that integralises them could make empires more stable for a cost of not converting the lands and minimum autonomy.

I know you might hate it, but it wasn't just in China, the Steppes or the Middle Eastern world where syncretism existed. There was information about christian syncretism as well (Treaty of Westphalia, for example)

 

[DukeLeto42]

The examples you've given here aren't syncretism. At its base, syncretism relies upon religious principles in which there may not be a singular, absolute Truth, which allows space for other faiths' Truths to be accepted as more-or-less equally genuine and merged into the "host" faith. To go through your examples in order:

1. The Dhimmi offsets the costs of other faiths, part of a religious belief system that recognized Christians and Jews as effectively flawed versions of the true faith, or "People of the Book." As such, it's not syncretism, but a recognition of rights for such people.
2. England was a rather firm Anglican nation after the Act of Supremacy (with some short exceptions), and while it did allow the continued existence of some faiths it was a matter of political expediency. This is not the embracing of minority faiths for their benefit, but the allowance of their existence because driving them out would be more trouble than it was seen as worth.
3. Lithuania is perhaps the most persuasive example of faith reconciliation, But still we're talking about faiths being viewed as equally valid from a political perspective, not the merging of faiths.
4. The Treaty of Westphalia established the principle of Westphalian Sovereignty, in which individual states had a degree of religious self-determination. Again, though, this is not syncretism or anything like it.

 

[AvengedK1ng]

Tolerance of heretics + tolerance of heathens from humanist and burghers estate should be enough to give +3 tolerance for them to not count towards religious unity, in previous patches this would also prevent ottomans converting the Balkans