Understanding is an act of Knowing the Darwinian world without knowing exactly how it is that this knowledge comes about.
Understanding precedes proofs & systems, hence Meaning precedes the investigation of "meaningless" matter.
The world is meaningful at all levels of analysis.
Attention is the currency through which consciousness transacts with Reality. The present moment is the only place where this transaction can occur. The only claim to Reality is here and now. Everything else is all fiddling around the maps, far from the territory.