It is essential when we look at deep time, or any sufficiently high-dimensional and detailed time series, to remember that we are only looking at a tiny slice. We always like to talk of "the tree of life", which might mislead folks into thinking that we get a clean cross-section of every branch of some high-dimensional tree. But, in truth, what we get is more like a tiny wedge cut out from a beanstalk with many central vines; we have only small leaves and cuttings from a mighty thick overgrowth of life.