The Complexity of the Universe

I don't think there exists a precise or really rigorous technical definition of complexity. There are various definitions, so I suppose I'm attempting to take a colloquial use of the idea of complexity and build on it. How the hell do you build complex things in a universe like that? And it's really urgent for us because we're complex things and the world we live in is complex. But at some level we're definitely talking about something real.