The term “realizing the mind and seeing one’s true nature,” stated concisely and comprehensively, means this: by thoroughly investigating the form and functioning of people’s “mind” (the original mind), one completely sees, realizes, and directly apprehends the wondrous substance and truth of “nature” (original nature), the source of life; thus one awakens from the dream of delusion, transcends birth and death, and realizes great nirvāṇa. An analysis of its meaning in detail is exceedingly profound and vast, for it is the essence of the whole body of teachings delivered by the Buddha during his lifetime. It may be said that the Tripiṭaka and the twelve divisions of scripture are all annotations on it. For now, we can only select its essentials and speak of them briefly.

Before discussing the content of realizing the mind and seeing one’s true nature, and how to realize the mind and see one’s true nature, let us first sketch an outline of mind and nature, so that we may more easily begin to analyze and discuss the meaning of realizing the mind and seeing one’s true nature.

Then what is mind? And what is nature? What is called mind is not the fleshly organ within our chest. Rather, it is the thoughts and ideas that arise when we encounter objects. Buddhist scriptures call these the reflections of conditions constituted by the six sense objects: the lingering images left by forms, sounds, odors, tastes, tactile objects, and dharmas. In brief, this gathering and arising is called mind.

That is to say, originally we have no mind—that is, no thoughts or ideas. It is only when objects such as forms are present that we receive their images through the respective conditions of the objects, generate cognition, distinguish their sameness and difference, assign them names, give rise to attachment and aversion, acceptance and rejection, and volitional activity, and thereby produce all manner of thoughts.

This mind arises through its conjunction with the environment; it does not arise independently on one side alone. Therefore, it is called the gathering and arising that is mind. This is what modern theories describe as “thought is a reflection of the objective environment.” As for a detailed account of its forms and contents, the Dharma Characteristics School’s Awakening of Faith in the Mahāyāna explains them very clearly: they may be divided into eight primary consciousnesses and fifty-one mental factors. To save time and space, I shall not discuss them in detail here. Readers are invited to study the Awakening of Faith in the Mahāyāna for themselves.

If mind is thus, then what is nature? Nature is the root from which mind arises; it is the source of mind. Modern theories regard it as the energy that gives rise to mind. Without it, mind could not arise in response to objects. Our ability to give rise to mind in response to objects is entirely its functioning.

It is without form or appearance, so the eyes cannot see it. Yet it can perform all kinds of functions, and thus it truly exists. The ancients compared it to the blue coloring in dye or the flavor of salt in water: though it cannot be seen with the eyes, it is in fact functioning. In Buddhist scriptures it has many different names, such as the One True Dharma Realm, suchness, tathāgatagarbha, Buddha-nature, true mind, great perfect supreme wisdom, and so forth.

It is only because sentient beings are deluded and unaware, and do not know of this wondrous substance, that from beginningless time they have merely combined with arising and ceasing, thereby becoming deluded mind. Thus mind and nature are originally one thing, like water and its waves; they are not two separate matters.

The world is now able to advance by leaps and bounds entirely through automation, and automation in turn depends on thermal energy. Without thermal energy, there is no motive power; without motive power, everything is still and lifeless. Likewise, our ability to think, work, create, and invent depends upon an inner motive power, and this power is the functioning of nature.

Therefore, although nature cannot be seen with the eyes, it truly performs every function. It is like electricity: though it cannot be seen, all illumination, operation, and so forth are its functioning. Buddhist scriptures call nature the essence and mind the function; nature is principle, and mind is phenomena. Yet within the Chan school, the two are often used interchangeably: mind is called nature, and nature is called mind. So long as we thoroughly understand their underlying meaning and clearly distinguish their boundaries, we will not be confused or perplexed by them.

Having understood the forms and definitions of mind and nature, we must further inquire: why does “nature”—the source of life—give rise to mind in dependence upon objects? And why do objects arise, so that birth and death continue in unbroken entanglement? We must also understand what the meaning of realizing the mind and seeing one’s true nature includes, and how we may realize it, see it, and escape birth and death. Let us now divide the discussion into five sections and examine it in detail.