I still have some confusion of the concept of spacetime as geometry. Specifically, what confuses me is causality related to this geometry. My understanding is that stress-energy of matter/energy curves spacetime, the curvature of spacetime tells matter/energy how to move, and dictates to particles the path they will take. Is this understanding correct? 1. Can we then talk about spacetime as pure geometry, as it seems to produce true effects? 2. How do you produce curvature in a mathematical object that effects causality of ordinary matter? Please correct any misconceptions, thanks.