Unlocking the Wisdom of the Heart Sutra

The Heart Sutra is a pithy, powerful text. If you understand it, says Ven. Guan Cheng, you understand the Buddha’s teachings.

Venerable Guan Cheng
1 November 2023
Tree silhouette with sunset in background
Photo by iStock.com / thad

The Heart of the Perfection of Wisdom Sutra, often just called the Heart Sutra, is very important in Mahayana Buddhism. It’s the summary of the Diamond Sutra, which is itself the summary of the Great Perfection of Wisdom Sutra—a sutra of six hundred volumes.

Though the Heart Sutra is a very short sutra, it contains many Buddhist concepts. If you understand the meaning of the Heart Sutra, then you have a very good grasp of the Buddha’s teachings.

The Heart of the Perfection of Wisdom Sutra is called the Prajnaparamita Hrdaya Sutra in Sanskrit. The first part of the title, prajna, can be subdivided into pra and jna, with pra meaning “supreme” and jna meaning “consciousness” or “understanding.” Therefore, prajna means “supreme understanding” or “supreme consciousness.”

The second part of the title, paramita, means perfection. The term can be subdivided into parama, meaning “the other shore,” and ita, meaning “that which has arrived.” So, if you follow, study, and practice prajna, you will arrive at the other shore. You will depart from this shore of confusion and suffering, cross the ocean, and get to that perfect shore of enlightenment and nirvana, which is free from suffering and mental defilements.

The last part of the sutra’s title, hrdaya, means “heart.” Here, “heart” does not just mean the physical flesh and blood heart, but rather the essence of the Great Perfection of Wisdom Sutra.

The Five Skandhas

In the Heart Sutra, Avalokitesvara Bodhisattva and Shariputra, one of the Buddha’s principle disciples, talk about the fundamental emptiness of all phenomena.

The most important lines of the Heart Sutra are “Avalokitesvara Bodhisattva, when practicing the profound prajnaparamita, perceived that the five skandhas are empty, and thereby became free from all suffering.”

Skandha literally means “heap,” “bundle,” or “aggregate,” because each skandha is a collection of many other things. We are made up of the five skandhas. That is, when they come together, we are created. The five skandhas are form, sensation, perception, volition, and consciousness.

The first skandha, form, is the physical body or materiality of any being or object, including sense organs. The second skandha, sensation, is physical feeling or sensory experience. This encompasses the physical body’s six sense organs (eye, ear, nose, tongue, body, and mind) in contact with the six sense objects (form, sound, smell, taste, bodily impression, and mental objects). Perceiving through our senses leads to the three types of sensations that make up our sensory experience: pleasant, unpleasant, and neutral.

The third skandha is perception or conceptualization—the mental process that recognizes and describes characteristics of form such as shape, color, length, pain, pleasure, etc. The fourth skandha is volition or mental formations. That is, when the six sense organs interact with the outside world, a reaction happens instantly inside your mind. You may not notice it, because it happens so fast, but you instantly interact with and respond to your perceptions, psychologically and emotionally. This mental function becomes the basis for future actions as well as for the arising of craving or desire.

Finally, the fifth skandha is consciousness or cognitive discrimination. This goes beyond perception and involves awareness and recognition, as well as memory, for understanding the six forms of consciousness. The six organs correspond to the six forms of consciousness: eyes see objects and create visual consciousness; ears hear sound and create auditory consciousness; the nose smells odors and creates the olfactory consciousness; the tongue tastes and creates taste consciousness; the body feels touch to create tactile consciousness; and the brain thinks to create mind consciousness.

Only the first skandha, form, is objective; it is the physical matter that exists. As we use our senses, we perceive through them. Sometimes we call the senses perceiving objective matter “empirical” and say that our senses are connecting with objects empirically. However, since the other skandhas are all mental, they are in fact subjective. With the skandhas, the subjective perceives the objective. When you say something objectively exists, it is objective that it exists and has matter. But when we perceive, think about, and analyze it, we do so subjectively.

It’s vital to understand what your senses are and do, because they interact with the outside world. The senses open the doors of your body to the world and open the world to your heart. At the same time, your senses also are the culprits of suffering. Your senses can help you, but they can also ruin you if you misuse them.

Normally, when we use our senses, we attach to what we can touch, see, hear, etc. But empirical evidence can be illusory. While we generally agree with each other, everybody perceives a little differently with their senses. When you see something red, you say, “This is red,” unless you’re colorblind. When a dog barks, you might say, “Oh, a dog is barking!” Yet there are some people who hear the dog’s barking as the howling of a wolf. Everybody’s different; it all depends on how you perceive. So, our senses are not trustworthy.

The skandhas give rise to the ego consciousness (manas vijnana), which interprets the subjective portion of sensation, perception, volition, and consciousness as self. This deluded view of the five skandhas as a “self” leads to ignorance and arrogance. If we see the five skandhas as employees, the ego consciousness is the “mind manager.”

Introspection means always considering that empirical thinking could be wrong. The Buddha said, “We cannot trust our senses. We must go introspectively, to see what we are seeing.” What needs to be considered is not what you see, but rather how you see it, or your process of seeing. The Buddha said, “Don’t just believe in what you see, you have to know how you see it.”

Understanding the process of perception (the process of seeing things, hearing things, etc.) is called experiential thinking. It requires being introspective and understanding your mind. This is what the Buddha meant when he encouraged us to understand the subjective skandhas. To know how your sensation, your perception, your volition, and your consciousness gives rise to the ego, you must turn from empirical thinking to experiential thinking.


The Four Interdependent Functions of Consciousness

There are four interdependent functions of consciousness that reflect the process of the skandhas and the mind manager.

The first interdependent function of consciousness is the object. Let’s take a sheet of paper as an example. The paper itself is an object, the portion that is seen. Second, there’s the subjective or the seeing portion. The subjective is a mental tape measure that’s used to see the sheet’s length and width. Third, there’s the self-witnessing portion, the portion that knows the subject has seen the object. The self-witnessing function cognizes how long and how wide the sheet of paper is. Fourth, there’s the rewitnessing portion, which completes the mental faculty. The rewitnessing function recognizes the accuracy of the measurement (i.e., “Is that correct? Is my tape measure accurate?”).

Though you may not realize it, every conscious effort and interaction involves these four interdependent functions of consciousness. Your eyes see an object, but your eyes are only a seeing function. You must stand behind your eyes to look at your consciousness. In other words, you must not be attached to the subject and the object. You must step back and say, “Is the subject I’m seeing something real?”

When you’re seeing someone with hatred and anger, then that rewitnessing portion can stand back and say, “I’m discriminating against this person and seeing them with anger. Could I see them with love?” The rewitnessing portion can also work in harmful ways. For example, your ego consciousness, the mind manager, can assess with your eyes and say, “Hey, here comes John and that guy is bad! He ripped me off, so I’m going to do the same thing to him!” In this case, you’re standing back as a third person, and you’re influencing your subject, yourself, to do negative things. The rewitnessing portion after this interaction is protecting your ego.

The same phenomena can create different conceptualizations. There’s a Japanese poem, where a man claps his hands. What happens? The birds are scared by the sound and fly away because they think somebody is shooting. The koi fish in the pond rush to the water’s surface, because the man always claps when he feeds them. And the man’s maids immediately begin to prepare tea because they think his clapping means he wants to entertain guests.

It’s the same clap of hands, but it creates different sensations: fear in the birds, happiness in the koi, and anticipation in the maids. It also creates different conceptualizations: the birds conceptualize the claps as an attack, the koi as feeding, the maids as a request from their boss to prepare tea.

Indeed, one clap contains all five skandhas. It contains form, sensation, perception, volition, and consciousness.


Let’s turn to another important line in the Heart Sutra that helps us understand why the five skandhas are empty: “Form is none other than emptiness. Emptiness is none other than form.”

Form, one of the five skandhas, refers to anything we can perceive with our senses—not just the form of something we touch, but also, for example, the form of a sound we can hear. Form refers to all phenomena, and in form we find sensation, perception, volition, and consciousness, that is, the other four skandhas. To say “Form is none other than emptiness. Emptiness is none other than form” means that form and emptiness are not different from nor apart from each other.

We ignorantly believe in the inherent substance and permanence of things. Emptiness is a fundamental concept in Buddhism. Emptiness does not mean nothing; in fact, emptiness allows for the existence of all things. Emptiness is full of everything, full of life. Therefore, emptiness does not have a negative connotation.

To be empty does not mean nonexistent. Instead, emptiness means empty of independent existence. Everything exists due to causation and dependent arising. Everything, both material elements and mental elements, are characterized by causation. So, things being empty does not mean that they don’t exist, but rather that they’re nothing but appearances. All things are nonself. They do not have “true reality.” All things are impermanent.

When we say that the five skandhas are empty, we mean that the five skandhas are empty of independent existence. It doesn’t mean that things do not exist, but rather that their existence is dependent on multiple causes and conditions. Nothing has its own inherent self-nature, because everything comes into being and is dependent on conditional causation.


The law of causation is cause and effect, that is, if there’s a cause, there must be an effect and vice versa. Form arises dependent on causes and conditions.

Forms do not have “own-being” or “own-becoming” (svabhava in Sanskrit). Svabhava is the notion that an object has its own intrinsic nature of coming into being; it does not depend on any condition, has no causes for its becoming, can avoid changing, and can exist permanently. But the existence of any object must belong to an existent reality, which means that it must be conditioned, dependent on other entities, and possessed of causes. Svabhava is by definition unconditioned, not dependent on other entities, and not caused. Thus, the existence of svabhava is impossible.

Therefore, everything is asvabhava, meaning it has “no own-being” or “no own-becoming.” This means that all things are nonself, empty, and without intrinsic existence. All things are changeable and therefore impermanent. Because of this impermanence, we experience suffering.

Let us use waves and water as an example. Waves rise from the water. Waves are not other than the water. Water is not other than the waves. Water and waves have the same nature.

We can also think of emptiness as gold, and jewelry as form. Earrings, rings, bracelets, necklaces, etc., arise from the conditional causation of gold. Ornaments are contained in gold, and gold is contained in ornaments. Because all phenomena arise from the conditional causation of emptiness, form is emptiness. If you want to realize the radiance and beauty of gold, you cannot do so apart from its various forms. Because one cannot experience emptiness without phenomena, emptiness is form.

Emptiness and form cannot be separated from each other. If the bulb and the electricity are separated, the bulb cannot show its functionality, and the electricity has no means to express its energy. Apart from the mind, there’s no phenomena. Apart from phenomena, the mind does not know. That is, phenomena exist because of the mind; the mind is conscious through phenomena.

When we realize this, a simple piece of paper comes to be not just a sheet of paper, but rather the many causes put together to constitute that piece of paper. From a tree, comes pulp; the pulp goes to a factory, which makes it into sheets.

On the other hand, when you burn paper, you may have the illusion of destroying it. You may say, “The paper is dying, because I’m burning it.” But the ashes from the paper will fall to the ground and become part of the soil nourishing new trees.

Therefore, there’s no limit, as far as changeability, as far as the conditional causality of that piece of paper. A limited, restricted view would say it’s merely a piece of paper, but a broad view of it shows that it’s boundless, limitless. How can you put a limit on a piece of paper? In the piece of paper, I see a beautiful tree. I see nourishing soil. I see a cloud. I see rain. I see sunlight.


The Importance of Practice

Commit this sentence to memory: “If we perceive that the five skandhas are empty, we become free from our suffering.” When you realize that the five skandhas are empty, then gradually, you realize an enlightened understanding.

Who am I? I am nothing but my senses. I’m nothing but body and mind reacting to environments, and I exist for a hundred years in the process of this reaction. So, we must understand further beyond these senses, beyond our environments, and what actually is this reaction. To do this, we need more than a superficial understanding.

If you read a book about emptiness and the five skandhas, you can easily understand what it means. But there’s a difference between perceived knowledge and enlightened knowledge. If you read a book, you perceive certain knowledge, but it’s just a perception.

It’s not enough to have an intellectual understanding of the Buddha’s teachings. You have to practice them. Then you get an enlightened understanding. Enlightenment is a deeper understanding through practice.

You’ve got to walk your path, not just talk about it. It doesn’t matter how many dharma books you read or how many dharma YouTube videos you watch. Some people are constant learners: they want to read, they want to listen, but they never practice. Don’t put your fashion clothes on the hanger! Put them on and walk the catwalk. Practice, practice, practice!

Once you understand all the conditions for the senses and the body to exist, contemplate how you use your body. How do you use your senses? What do you use them for? Some people use their body to steal, their tongue to lie, their mind to create harmful weapons. Do you appreciate the reality of the senses and do you use them for enlightenment? Do you use them for compassion, for helping, or do you use them for hurting, for selfishness, and for egoistic actions?

Nowadays, what are we searching for? We’re searching for sensual pleasures. We want the eyes to enjoy what we see, the nose to enjoy what it smells, the tongue to enjoy what it tastes. We want to create physical and mental sensual pleasure. But pleasure is impermanent. In the process of searching for it, a lot of mental disturbances come up. So, we’re using our senses to create suffering. Your eyes, ears, nose, tongue, body, and mind are creating suffering for you.

Ask yourself: Have I hurt people in my pursuit of sense pleasure? Have I been conducting my life in the most meaningful way?

The Buddha’s teachings do not say, “Worship me, because I’m the Buddha. I can take you to heaven, to nirvana.” The Buddha’s teachings say, “Learn about the world, learn about yourself—your body and your mind.” The buddhadharma is about understanding yourself; it’s not about faith in the Buddha. The Buddha taught us to realize understanding by first training in meditation. Know your mind and detach yourself from your ego. Analyze your mind. Look at it with enlightenment.

What do you learn from conditional causation? You learn that you must build conditions for yourself to be successful in this life, in this spiritual odyssey, so that you’ll become enlightened. You must build the conditions for you to stop worrying, for improving self-confidence, for being happier.

You are a conditions-builder! Why wait for the future? You can change the present. You can be away from suffering. You can eradicate jealousy, hatred, disappointment, and worry by building up the right conditions. It’s up to you! It’s not up to the Buddha, not up to God. As a meritorious conditions-builder, you build conditions that benefit yourself, society, and all sentient beings by abstaining from stealing, killing, lying, sexual misconduct, and intoxication, as well as resisting being egoistic, angry, hateful, and jealous.

You can build conditions for yourself that benefit yourself, other people, society, and all sentient beings. You just have to explore the teachings, understand them, review them, and practice them. You have that ability.

Venerable Guan Cheng

Venerable Guan Cheng is the abbot of the International Buddhist Temple in British Columbia, Canada. He has published various books in Chinese, including Commentary on the Heart Sutra and Commentary on the Diamond Sutra.