Anyone who knows me knows of my interest in consciousness and reality (see tags below for more). When it comes to understanding reality, I’m gonna go with one of the following. (or some combination.)
Monism is the view that all reality is fundamentally one substance or principle. Everything in the universe is ultimately the same kind of thing. This can be physical (everything is matter) or mental (everything is mind), or something else entirely.
Panpsychism, on the other hand, is the idea that consciousness is a fundamental and ubiquitous feature of the universe. According to panpsychism, all things have some form of consciousness or experience, even if it’s very basic, down to the smallest particles.
So, while both can be viewed as “unifying” theories, monism is about the nature of reality being one substance, whereas panpsychism is about consciousness being fundamental and present everywhere.