Brute emergence, or strong emergentism is the anti-scientific theory that things are capable of having properties that aren't built out of the properties of the building blocks they are made out of. The other form of emergence, known as weak emergence is compatible with what we know about science, because many things can have properties at a macro scale that are meaningless at a mini-scale, but that you can extrapolate how they would act when put together. For instance, one water molecule is not properly defined as a fluid when sitting by itself, but it has the properties that are called fluid when a lot of them are put together to react. Etc etc. Most people don't think about this day to day, but are fine with the idea once having it explained to them for the most part.
However, it seems like there's one obvious exception that atheists are almost as likely to demand be treated as an exception as religious people are. And that's consciousness. Despite being okay with recognizing strong emergence as non scientific in other areas, suddenly they are okay wiggling and skirting around the fact that many of them think consciousness simply comes into existence out of nowhere at specific times, rather than being an abstract universal property of the world in general that simply manifests in more visible ways at times. And will actively shy away from having to admit that abstract latent conscious properties would have to be immanent in the physical world as a whole in all matter in less visible ways to make sense of its presence scientifically. In other words, its more obvious appearance being a case of weak emergence, rather than strong emergence.
The exception, or "strong emergence" as it is called has another historical name. That name being "magic." What's more, if you accept that things can generate properties that aren't built out of their building blocks, its inconsistent to not accept this as a viable explanation at other times. Since it would be rather bizarre if this happened in only exactly one type of case in all the universe. (To say nothing about the fact that if the properties aren't part of matter itself, its unclear where it even comes from.)