In the Sixth Patriarch Hui-neng’s Platform Sutra (hereafter, PS) he explains to us that the very substance of our ordinary thoughts is True Reality. This means that our thoughts are not just made of nothing. Towards the end of section 17 in the PS Hui-neng sermonizes that, “True Reallity is the substance of thoughts; thoughts are the function of True Reality.”
His words, I must say, are quite eloquent and to the point. What his words further suggest is that in ordinary sensory consciousness we only perceive our thoughts—never the universal substance from which they are made. Making matters even worse is the strong habit of trying to conceive of this substance. But what is formed is not True Reality—it is illusory and false.
What this means for the Zennist who has yet to directly see pure Mind, or if you like, True Reality, is that their main goal should be to avoid creating picture thoughts of such a Mind or Reality. To be sure, such a pure Mind cannot be conceived or mentally envisioned. However, this is not to suggest that we should do nothing or just sit in a state of imperturbability or blankness. To do so is to abide in illusion perhaps not even realizing it.
Commenting from section 14 of the PS, perhaps the best advice in order to behold pure Mind comes from the side of the straightforward Mind (riju-citta) which is also the samadhi of oneness.
Laying this out, in order to see the substance of our thoughts we first have to begin to do so with a mind that actively penetrates through its mental images as if they were insubstantial and gossamer. This is really pure action without attachment—the work of transcendence. It is analogous to looking at a beautiful reflection on a still pond being able to see first the water then the reflection.
By forwarding (riju) our mind in this manner we are setting up the necessary condition of our awakening, that is, of eventually perceiving pure Mind (cittamatra) which is the state of Bodhicitta. From Bodhicitta (also, bodhicittotpada) commences the Bodhisatttvic path since this awakening is only initial and not yet complete. When it begins to become complete these words express that state: “What is there to cultivate in the bright, bright primordial light that is self-knowing, does not split, does not move, is undefiled, and does not abide?” (Bsam gtan mig sgron [Zen of the Enlightened Eye])