Invisible matter, invisible brains?

Abstract

Cosmology finds itself in a paradoxical situation. We know everything and nothing. After years of accumulating evidence and debate, there is a consensus model about the makeup of the cosmos, known as Lambda Cold Dark Matter (ΛCDM), for reasons explored below. The Universe seems to have no spatial curvature, is clumpy on small scales but smooth on large scales, and is expanding at a well-measured but accelerating rate. The contents of the Universe are divided between ordinary matter, dark matter, and dark energy. This phenomenological model is exquisitely constrained by observations, but it is not known what dark matter and dark energy actually are or why the Universe is this way.