There is only one phaneron, and there is no difference between this and the experience of this. In its Firstness, the buddha-nature is the buddha.
All buddhas are realization; thus all things are realization. Yet, no buddhas or things have the same characteristics; none have the same mind. Although there are no identical characteristics or minds, at the moment of your actualization, numerous actualizations manifest without hindrance. At the moment of your manifestation, numerous manifestations come forth without touching one another. This is the straightforward teaching of the ancestors.
Do not use the measure of oneness or difference as the criterion of your study. Thus, it is said, “To reach one thing is to reach myriad things.” To reach one thing does not take away its inherent characteristics. Just as reaching does not make one thing separate, it does not make one thing not separate. To try to make it not different is a hindrance. When you allow reaching to be unhindered by reaching, one reaching is myriad reachings. One reaching is one thing. Reaching one thing is reaching myriad things.— Dogen, ‘Gabyo’ (Tanahashi 2010, 444)
To ‘reach one thing,’ 法 通 (ippō tsū), is ‘the total experience of a single thing’ in Hee-Jin Kim’s translation:
‘The total experience of a single thing’ does not deprive a thing of its own unique particularity. It places a thing neither against others nor against none. To place a thing against none is another form of dualistic obstruction. When total experience is realized unobstructedly, the total experience of a single thing is the same as the total experience of all things. A single total experience is a single thing in its totality. The total experience of a single thing is one with that of all things.
— Dogen, SBGZ ‘Gabyo’ (Kim 1975, 66)
In the Firstness of its Thirdness, there is no difference between these two translations of ‘Gabyo’, or between the total experience of a single thing and 法 通.
For Dogen, the enlightened person was adept at appropriating the semantic possibilities of ordinary words in order to express and act out the extraordinary, and even the ineffable, according to the situation. Dogen’s characteristic way of thinking here in connection with the use of language was that the meaning of an ordinary word was totally exerted so that there was nothing but that particular meaning throughout the universe at that given moment. This was the idea of the total exertion of a single thing, which was central to Dogen’s entire thought.
— Kim (1975, 88)
The total exertion of a single meaning is a pure expression of what Peirce called thought, which comes naturally to children learning to use language, before they learn about the difference between words and meaning, or thought and expression.
The child, with his wonderful genius for language, naturally looks upon the world as chiefly governed by thought; for thought and expression are really one. As Wordsworth truly says, the child is quite right in this; he is an “eye among the blind,”
“On whom those truths do rest
Which we are toiling all our lives to find.”
But as he grows up, he loses this faculty; and all through his childhood he has been stuffed with such a pack of lies, which parents are accustomed to think are the most wholesome food for the child,— because they do not think of his future,— that he begins real life with the utmost contempt for all the ideas of his childhood; and the great truth of the immanent power of thought in the universe is flung away along with the lies.— Peirce, MS 464-5 (CP 1.349, 1903)
Hence the advice of all the sages that realization of this great truth, or of the buddha-nature or the Kingdom of Heaven or the Firstness of Thirdness, depends on learning from little children.