Title: "Causality and the microstructure of spacetime"
Physicists are still searching for a complete theory of quantum gravity
which would explain why spacetime is what it is, from the tiniest Planck
scale up to the scale of our universe. I will describe attempts to
generate such a "quantum spacetime" dynamically, starting from a small
number of fundamental physical principles. Exciting new results reveal
that requiring geometry to be causal at the very smallest scales plays a
crucial role in obtaining quantum geometries that resemble our
four-dimensional universe at macroscopic distances.