When we say that what people understand to be their self is illusory, or “empty,” people freak out
a little bit a lot. It seems like such a cold, hard, alien view to imagine. And then what really fries the whole understanding for them completely is when you try to let them know that this “emptiness” is just a word for “completely full, without-any-separation, all-encompassing, the-everything, total substance.”
But it is very easy to understand that possibility, at least conceptually, even without sitting long retreats in some icy mountain valley. (Although the conceptual level of understanding will never truly substitute for the lived attainment of that.)
The being of “space” is the first thing your eyes encounter every single moment that they are open, and you move through it constantly. It seems to be “empty,” devoid of any particular shape or color or characteristic, void of weight or coming or going, void of “inside” or “outside” dimensions. And yet space contains all things. It contains everything. It is completely “full.” The mass of every atom is 99.99% “empty” — for all intents and purposes, the very existence of matter is “emptiness.” How much truer, then, is that vague, shape-shifting thing we identify with as my “self”?
In several sutras, the Buddha — after doing his damn hardest to explain the view of non-self, in the forms of words — says things like “If, after hearing this explanation of the nature of emptiness, your head has not exploded with this, then you have made good karma for true understanding.” It’s the same point.