Are your thoughts real? What about the things you see when you dream? Are those images real? How about your emotions? Are they real?

These things are not material, but that doesn't mean they aren't real, does it? Whether the immaterial is a product of the material (or vice versa), while an interesting question in itself, is inconsequential to the point, which is that there is more to reality than the material.

As much as we've learned about physical reality, we don't know everything about it, and that has been the primary focus of human beings for much of history. About immaterial reality we know much less (at least in western cultures) because it often eludes the scientific method. Compared to the material it seems intangible and flimsy; therefore, we reject it as 'unreal', 'untrue'.

The immaterial does exist though, and clearly the material and immaterial are not only inseparable but interdependent; two sides of the same coin. There is no independently objective physical reality, because the physical universe is not unaffacted by 'immaterial' thoughts and observations. It's all one seamless process.

So, to the question in the title of the thread I would say: they're already unified. They just aren't acknowledged as such by those who reject the possible existence of yet unknown immaterial truths.