We are all, as a rule, habitually mistaking the nature of things.
Unfortunately, we do not believe that this is the case. The apparently concrete and substantial nature of our surroundings, as we ordinarily perceive them, fixes in our minds the absolute conviction that we understand how things are. For example, we believe we understand that trees are trees, flowers are flowers, and mountains are mountains.
The source of arising of all that we perceive is so substantially different from, and alien to, the level of consciousness that we generally inhabit that we are, in fact, unable to know it or to describe it in words. Hence the repeated admonitions by Dogen that no matter what we think something is, it isn't. We must not think of enlightenment or no enlightenment, we must not think of realization or no realization--in fact, we must not think.
In a supreme twist of irony, we are left talking about silence and explaining that things should not be explained. If I had a nickel for every text I have ever read that goes on endlessly in words trying to explain how words cannot explain the truth, I would already be in retirement.
One of the refreshing things about Dogen is that he did not fall victim to this type of hypocrisy. He did not discount the value of words; nor did Gurdjieff. Au contraire, both of them insisted that it is possible to understand significant things by means of the intelligence, and by means of the words we use to communicate.
They both also insisted that what we would understand would be quite different than what we think we are going to understand.
Truth, in other words, has a tendency to absolutely confound expectations. Perhaps that is one of the first signs we have encountered it.
We must get rid of all our assumptions. In immediately abandoning everything that has come before, can we clear the way to grasp what is immediately before us, within this moment? Can our awareness be used as a sword to cut off the past, cut off the future? (See Christ's comments in Matthew, chapter 10, 34-40.)
For me, pondering this question this morning in contrast to both the experience of this morning and the thoughts of this morning, I see that Truth is a substance. It is the only substance, and everything that we see around us and encounter is just a reflection of that substance.
What do I mean by substance?
There is a scent, a perfume that penetrates and suffuses all of reality, which in some moments I catch a whiff of. There is a clarity that lies on the edge of perception which penetrates this thing called "I" and dissolves it completely.