When a person is in such a psychedelic experience, his sense of self disappears completely, and in that experience there is no sense of being the bearer of properties.
If so, some claim that the self is only an illusion, and in fact when part of the brain is not functioning there is no self anymore, because there is no sense of being the bearer of properties.
In short, our intuition that there is a bearer of properties disappears in a psychedelic experience, and this is (perhaps) an indication that the self is an illusion created by the brain, and when the brain does not function (in certain areas), the illusion stops.
What I was trying to say is that even if we claim that within the experience that same self still remains, it has no content at all and that is just empty words, because there is no sense of self there at all, only a feeling of complete blending with everything else, with no separateness whatsoever

So the question is: is a psychedelic experience an indication that there is no self? How would you explain this experience and the fact that everything there is together without distinctions?

By that logic, when I close my eyes I don’t see, so sight doesn’t exist? The self has no content. The self is a framework to which the contents belong. Like the properties of a thing that belong to an object. In itself, it is the subject of the properties.

I understand. If so, how would you explain the psychedelic experience? In your analogy to sight, we would say that a blind person is physiologically impaired and therefore cannot detect the sight that exists. So would you say that a person inside a psychedelic experience is physiologically impaired and therefore cannot detect the self that exists? I assume you know the claim that says that “everything is one” (that is what people experience under the influence of the drugs). If we connect this claim with the claim (which, to the best of my knowledge, you accept) that subjective experience is something one cannot argue with (if I am in pain, no one can tell me I am mistaken), then we arrive at the conclusion that the claim that there is no self and everything is one (and that the feeling that the self exists is merely an illusion) is just as valid as the claim that there is a self, and there is no way to object to it—isn’t that so?
As long as we do not claim that someone inside a psychedelic experience is undergoing a physiological defect (like blindness) or a mental defect (hallucinations as in schizophrenia), I don’t see how one can defend the position that there is a self which is the substrate on which the properties exist, and that this is the truth, rather than what is experienced under the influence of the drug.

And in addition—even if we say that this is a hallucination and a physiological/mental defect (similar to blindness), what do we base that on? After all, the difference is purely which area of the brain is active and nothing more.

I do not understand the statement that everything is one. It sounds to me like a string of words devoid of content. A person in a psychedelic experience is closed off to some things and exposed to others. Like sleep. I do not see what here requires explanation. It is not a defect but a certain state.

And regarding the area in the brain, that is not relevant at all. There are areas in the brain that operate in all our mental activity. Does that mean there are no mental acts? We carry them out by means of the brain (the direction of influence can be from the mental to the brain or vice versa).

I completely understand what you are saying, and still there are 2 claims that require explanation in my opinion:

1. You gave the example of sleep, but if a person were to claim that what he saw in sleep is reality, we would tell him that it is not true, because in dreams one does not see reality (usually, if we take a cautious approach) but experiences something unreal. Clearly the mental state of dreaming is real, but the content of the dream is not real and does not reflect what exists in reality. Therefore one can say the same about psychedelics: the experience is an experience, as you said, but the content—the information about reality contained in the experience—is either true information or not. So is the experience that “everything is one” real, or not (like in a dream)?

2. And now to the heart of the matter: it is impossible to explain what the color red is to a blind person, and in the same way, so people who have experienced psychedelics would claim, it is impossible to explain what this “everything is one” that they experienced is. And therefore the brain becomes relevant here: we know that a blind person does not see reality (that is, reality is not black and without objects, but rather full of different objects) because he lacks a certain part of the brain (or certain connectivity between parts of the brain). In fMRI scans that were done, they showed high and unusual connectivity between parts of the brain during the psychedelic experience, and perhaps that means they understand something we do not understand. How does one deal with the following claim that could come from people who have had the experience (and by the way, almost all of them speak about essentially the same things): “Just as you cannot explain to a blind person what red is, so I cannot explain to you what ‘everything is one’ means, but just as you are sure that the red you see exists, so I (and many others like me) know what we are talking about when we say ‘everything is one,’ and that is definitely reality. To know it, you will have to experience it.”

I would also add that in the context of morality, we understand what morality is by reflecting on it. And someone who does not understand what we are talking about we would define as a psychopath. And yet we will never be able to explain to him what good is. If so, the same claim could be made by the people who have experimented with psychedelics.

1. Correct. What is the question?
2. I explained that I do not understand what “everything is one” means. Now you say that you also cannot explain it to me. So there is no point in the discussion.
And indeed, this discussion is not going anywhere. I’m done.

I share the feeling that the discussion has run its course, because of the dead end of undefined terms.
And yet I will just add that in order to talk about that feeling, one has to experience it, just as in order to understand what red is one has to experience it. Therefore, if there is any meaning to the discussion, it is about this point: the claim is that there is knowledge experienced there that can be known only through the experience itself.