In the world of Buddhism, "no-self" is understood in such a way that, according to what I read somewhere, there is a record (or rather, a tradition recorded hundreds of years later) of the Buddha asking Hindus a question, "Have you seen the Atman?" and the Hindus answering, "No." Based on this, modern Buddhism generally teaches the concept of "no-self."

This story is quite famous, and Buddhism is rooted in practice and enlightenment, so it seems that practice and enlightenment are more important than doctrines and worldviews.

When I reread this story, it is true that, as a certain logic, it does not necessarily stand on its own. However, interpreting the Buddha's words directly and asserting "no-self" and that the Atman (true self) does not exist is an interpretation that only someone who has not experienced Samadhi (trance) would make, and it is a result of purely academic learning.

Once one has experienced Samadhi, even if the expression is different, one can understand the explanation of the Atman (true self), and although Hindus often have many misunderstandings because they have not experienced it themselves, they should have been able to understand what the Atman (true self) is trying to say. Even so, the fact that the Buddha still denied the Atman (true self) in a dialogue with Hindus suggests that the person he was talking to was probably very dense.

Furthermore, the Atman (true self) is essentially identical to Brahman and is "part of the whole," which is equivalent to oneness. However, in reality, although we do not know the actual situation at that time, it is possible that the Atman (true self) was strongly connected to the ego or the sense of "self," and that this was hindering enlightenment. Although it is not inherently something that hinders enlightenment, depending on the interpretation, the concept may have been hindering enlightenment at that time.

Another possibility is that the Buddha (Buddha) was not yet enlightened when he asked that question. Even this possibility is not just a mere guess, but I remember reading about it in a book some decades ago, but I could not find it immediately. If this story is true, then the fact that the Buddha denied the Atman (true self) before enlightenment is not necessarily related to the true meaning of the Atman (true self). The most useful part of the Buddha's teachings is what he said after enlightenment, and even before enlightenment, his actions were reasonably informative, but when it comes to such an important matter, it is better not to lightly interpret it based on uncertain information from before enlightenment and conclude that it is "no-self."

In reality, the Atman (true self) and the ego consciousness are on different levels. In yoga, the ego is called "Ahamkara," which arises as a reaction to perception (Buddhi). Yoga teaches that Ahamkara is actually an illusion that does not exist. In that sense, if the ego (Ahamkara) does not exist, then the interpretation of "no-self" certainly holds true. However, it does not mean that the Atman (true self), which exists on a different level, does not exist.

I believe that even someone like the Buddha would have understood these things.

Therefore, it is possible that people at that time misinterpreted it in that way, or that he said it in order to prevent people from being misunderstood or misled.

In any case, I personally find it difficult to accept the interpretation that the Buddha denied the Atman (true self) as a straightforward matter. I think it may simply be a story about correcting those who claim to be enlightened but have no experience, and who are just talking about theoretical knowledge.