When you identify with something, a false concept of "I" arises, which is the ego. If you let go of that identification, if the time is right, you may realize that an infinite self is spread out endlessly behind it, or perhaps not yet.
If you realize it, that is oneness, but if you don't realize it, you don't know oneness.
This is not about "stopping" thoughts.
There are many people who know this intellectually but do not actually know oneness. There are many people who study religion or philosophy in college and claim to "know," but they may actually just be "objectifying" it.
This is a very common misunderstanding.
In the context of oneness, the identification of thoughts and the self, as mentioned earlier, can also be said to be "the same," but that is only oneness at the level of oneness. What is commonly called "I" is the ego, and the ego is the concept that is the basis of the "self," which is the concept that yoga calls jiva. By letting go of the identification of "thoughts" and "I," which is the beginning of that false concept, if you are ready and the time is right, you will realize the infinite consciousness and self that is spread out behind it.
If the time is not right, it simply becomes "the ego disappears," and the ego, which has lost its place, will seek various ways to survive and try to prolong its existence. It will make various excuses and look for ways for the ego to remain. And it will convince itself that "I already know oneness," even if it has not yet reached that state or knowledge, arrogantly believing that it "already understands." This is a common misconception, so don't worry too much about it.
Even if you study various things in academia or religion and claim to know oneness, in many cases, you are simply "already understanding" as a reaction of the ego, and you do not actually understand. That is often the case.
No matter how much you explore "what is the self" intellectually, if you cannot open your heart to the infinite oneness, you cannot see it. In the first place, oneness is unnecessary, but most people have that barrier.
Furthermore, some people even use this kind of understanding to separate themselves from others. This is either a form of "mounting," or it is a way to keep others away, or it is for the satisfaction of the ego. Believing that "I already understand oneness" itself creates a separation, and oneness, which should be a unified concept, becomes isolated knowledge floating in the air, like a sign hanging on a board.
True oneness is to let go of the false identification of the self with thoughts. When thoughts arise, they are reflected in the mirror of the self, and a concept arises that it is "you." Just let go of that false concept.
When you say this, some people may immediately associate it with the knowledge that is often circulated in the world and think, "Oh, so it's about stopping thoughts." But that is not what it means. The thoughts themselves are a necessary "tool" as a function of the mind, so you can use them skillfully if needed. Since it is a tool, it is not "I." However, in many cases, people identify thoughts and the self, saying, "I think, therefore I am."
Even if you understand these individual concepts, it is often difficult to put them into practice. You need to let go of the identification of the self with thoughts, but in many cases, people simply "think they understand" (as a result of the ego's self-defense mechanism). The ego is protected, the ego is maintained, and people continue to believe that "I already understand," and "I have already reached oneness," and that state continues for a long time. That is what most people end up with. Very few people actually reach oneness.
There is a story like this in a folktale.
An angel and a demon heard a story about oneness from a wise man. Both the angel and the demon immediately understood, but the angel questioned itself, "Can I really say that I know this?" and eventually reached the answer. On the other hand, the demon thought, "Oh, so that's what it is," and believed that it already knew the answer. And the demon did not reach the answer.
This happens often.
And there are many people who are justifying their actions by saying beautiful things.
The true goal is a very simple thing, but it seems that few people who realize that take the first step towards that goal.
Most people are protecting their ego, nurturing their ego, and continuing to believe in the false concept that "I understand."