The Sanlun school, also known as the Three Treatise school, is a Chinese Madhyamaka school that emerged during the Tang dynasty in China. This school is based on the teachings of the Indian philosopher Nagarjuna and his concept of emptiness. The Sanlun school places great emphasis on the concept of self and non-self, and their understanding of these concepts differs from other Buddhist schools.

According to the Sanlun school, the concept of self is an illusion. They believe that all things, including the self, are empty of inherent existence. This means that the self is not a fixed, permanent entity, but rather a constantly changing and impermanent phenomenon. The Sanlun school sees the self as a mere convention, a label we use to refer to the collection of ever-changing physical and mental elements that make up our being.

The Sanlun school also rejects the idea of a permanent, unchanging soul or self. They argue that if the self were to exist inherently, it would be unchanging and independent of causes and conditions. However, since everything is subject to causes and conditions, including the self, it cannot exist inherently. Therefore, the concept of a permanent self is considered an illusion by the Sanlun school.

On the other hand, the concept of non-self, or anatman, is central to the teachings of the Sanlun school. They believe that by understanding the emptiness of the self, one can also understand the emptiness of all phenomena. This leads to the realization that there is no separate, independent self, but rather everything is interconnected and interdependent. The Sanlun school sees this understanding as crucial to attaining enlightenment.

In addition, the Sanlun school also emphasizes the Middle Way, which is the path between the extremes of eternalism and nihilism. They reject the idea of a permanent self, but also reject the idea of non-existence. Instead, they believe that the self and all phenomena exist conventionally, but not inherently.

In conclusion, the Sanlun school views the concept of self and non-self as essential in understanding the nature of reality. They see the self as an illusion, and the understanding of non-self as crucial to attaining enlightenment. By rejecting the idea of a permanent self and understanding the emptiness of all phenomena, the Sanlun school offers a unique perspective on the concept of self in Buddhism.