In the Condensed Perfection of Wisdom Sutra, Buddha says:

`If you search for your body with wisdom, you cannot find it.`

This implies that if we search for our mind, our I, and all other phenomena with wisdom we cannot find them.

This proves that the things that we normally see do not exist. If they exist, why can we not find them when we search for them with wisdom? If the things we normally see actually exist, why can we not find them when we search for them with wisdom?

Because when we search for them with wisdom we cannot find them, this proves that the things that we normally see do not exist. However, when we search for our body, our I, and other phenomena with ignorance, normally we believe that we have found something. But in reality we have found the wrong object, that is inherently existent things, which do not actually exist.

How do we search for our body with wisdom? We normally see our body within its parts, such as the hands, legs, and so forth. This way of seeing our body is mistaken. Now, through relying upon Buddha’s teachings, we should contemplate as follows:

Are the individual parts of my body, such as my hands, legs, and so forth, my body? No, because these are parts of my body. My body is the part-possessor. The possessor and the possessions cannot be identical, cannot be one.

The collection of these parts is also not my body because it is a collection of things that are not my body.

I have no body other than its parts because when all the parts disappear, the body will also disappear. Therefore, I have no body other than its parts because when all the parts disappear the body will also disappear.

Through searching like this we will realize that the body that we normally see does not exist and we will perceive a mere absence of the body that we normally see. This mere absence of our body that we normally see is the emptiness of our body and is the real nature of our body.

This way of searching for our body with wisdom should be applied to our I and all other phenomena so that finally you can understand that all things, all phenomena, that we normally see do not exist.

As I said before, we normally see our body within its parts. This way of seeing our body is mistaken because the body does not exist within its parts. We already checked – the individual parts are not our body, the collection of the parts is not our body, and there is no other body, so the body does not exist within its parts. But we normally see our body within its parts. This way of seeing our body is mistaken because the body does not exist within its parts.

But the body exists as mere name. In the Perfection of Wisdom Sutra, Buddha says:
`Shariputra, form aggregate is mere name. Likewise, space is also mere name.`
In this context, `space` means emptiness. In these words Buddha is saying that form aggregate, such as our body, our house, and so forth, exists as mere name. Space-like emptiness also exists as mere name.

For example, when we search for our body with wisdom, instead of finding our body it will disappear. What remains is the mere name of our body. This mere name of our body is the conventional truth of our body. The emptiness of our body is the ultimate truth of our body. These two truths are one nature and inseparable. The same nature, inseparable. For example, our body itself is conventional truth. The emptiness of our body is ultimate truth. These two – our body and the emptiness of our body – are one nature, inseparable.

As it says in the Heart Sutra:

`Emptiness is not other than form …`

`Form` means body.

`Emptiness is not other than form’

`… Form also is not other than emptiness.`

These two are one nature. This is called the `union of the two truths`

When we understand clearly that our body and the emptiness of our body are one nature, we have understood the union of the two truths, so that our understanding of emptiness is now complete, authentic.

Therefore, we are not denying the body. The body is conventional truth. The emptiness of the body is ultimate truth. These two truths are one nature, inseparable.

So if we think carefully, do the things we normally see exist? No, because they are inside emptiness, not outside of emptiness. In the space of emptiness, not outside, because they are inseparable.

This subject is immensely important, the most important subject for realizations of both Sutra and Tantra - to attain liberation and enlightenment. The most important subject, object of knowledge. So Je Tsongkhapa says:

`The essence of Buddhadharma is emptiness.`

This means understanding emptiness. The realization of emptiness is the essence of Buddhadharma.

There are many different levels of scholar. The supreme scholar is the scholar who knows the emptiness of phenomena. There are many Spiritual Teachers or Spiritual Guides. Among these, the Spiritual Teacher or Spiritual Guide who realizes the emptiness of phenomena is supreme. Je Tsongkhapa said.