What the Buddha is saying is that the truth doesn’t lie in either speech or silence. We should investigate the facts, as the commentary says.
Although the Buddha did not speak a single word, it cannot be said that he remained silent either. Wordless is not the same as expressionless. It’s in that expression that most of the dharma is transmitted. People cling to the words, but within those words, or beyond those words, or hidden in those words, is the real teaching. It’s not the words themselves.
The other assumption we make is that silence is the answer. Was Vimalakirti silent when he was asked by Manjushri: “What is the non-dual dharma?” It was definitely wordless, but did he not say anything?
Can we appreciate this? Can we really appreciate what human communication actually is, and how it is understood from a Buddhist perspective? What about invocation and expression? If there’s no self, how do you understand them? Communication means sending information from A to B. Invocation means imaginative recreation. Expression means a self is expressing something, sending forth something. You need a self for all of those things. How do they function when there’s no self, when body and mind have fallen away?
Dogen says that without words and letters we can express ourselves in myriad ways; we do express ourselves in myriad ways. We’re constantly expressing ourselves. He says:
Even deaf mutes have expressions. Do not judge that they cannot possess any expression. Those who create expressions are not necessarily limited to those who are not deaf mutes. Deaf mutes do express themselves. Their voices should be heard and their utterance should be heeded. Unless you identify yourself with them, how can you meet them? How can you talk with them?
Are we aware of how much we say without uttering a word, and without being silent?
These teachings, the commentary says, are ...like thunder, resounding through space and time down to this moment itself. Can you hear it? How do you create the space for it to be heard? If you’re talking to yourself, you can’t hear it. If your mind is constantly moving, you can’t hear it. That’s why zazen is so important and so powerful. It teaches us how to come home to the moment, to be present in that elusive split second of time which arises as it leaves, immediately. The moment: that’s where our life is.
These teachings transcend affirmation and negation, being and nonbeing. They are a reality that’s neither dualistic nor monistic. When we say non-dual, we think that unity is on the other side of it. It’s not. It’s not fragmented, nor is it whole. It’s not being and it’s not nonbeing. It’s not existence, nor is it nonexistence. That’s what the buddhadharma is constantly pointing to. That’s the realization of annutara-samyaksambodhi, the supreme enlightenment that the Buddha expressed as his life.
All phenomena in the universe—audible and inaudible, tangible and intangible, conscious and unconscious—are the self-expression of the buddha nature. Nothing is excluded from this. Dogen’s own teachings extended even into supernormal powers and into the realm of tantra—charms, spells, dharanis—which he understood and taught in a unique way. Tantra and tantric teachings, too, are based on a kind of communication that is neither speech nor silence.