I like your reply to the reader who asked about the existence of the self. All good points! I wonder what you think about the following different response to people like Harris (or Hume)... It seems to me that they just don't adequately support their claim that no self can be known or discovered or experienced. A few thoughts:
(1) It just might be true that the self isn't found "when looked for in a more rigorous way", if meditation (or whatever) is a rigorous way of looking for it. But does that support the conclusion that we don't experience the self in some other way--for example, without "rigorously" looking for it? Phenomenologically, it seems to me that I'm aware of myself most of the time. I can feel "self-conscious", for example, if I'm uncomfortable or worried how other people perceive me. At other times, when I'm lost in the moment, I'm less aware of myself. Why doesn't this kind of phenomenological fact (or seeming fact) count as evidence that there is such a thing?
BV: It is an interesting question whether the experience of self-consciousness you describe is evidence against the claim made by Sartre, Butchvarov, et al. that that there is no self or subject who is conscious. It is not obvious to me that it is. Suppose I feel self-conscious in a social situation. I am perhaps reading a paper before a large group of people I do not know. Maybe it's part of a job interview! My one chance at securing a tenure-track position! A latter-day Humean might offer the following description. There is in the speaker awareness of: the audience, the expressions on their faces, the body and sensations in the body such as dryness in the mouth and sweat forming on the forehead, a bit of queasiness in the stomach, the less-than-confident sound of one's voice, feelings of anxiety, nervousness, self-doubt, and so on. There needn't be a self that is aware of all this physical and mental data. There is just (subject-less) awareness of it.
It is important to bear in mind that when a philosopher asks about the existence of the self, he is not asking about his possessions or his body or any part thereof, or his memories or any introspectible contents. He is not asking about what ordinary people identify as themselves. People identify themselves with the damndest things, their cars, their Zip codes, their bodies. For all of that is 'on the side of the object.' What he is asking is whether there is a subject distinct from all of that, distinct from the body and from the empirical psyche.
A much stronger objection to the Humean invokes the thesis of Brentano that every primary intentional awareness is accompanied by a simultaneous secondary awareness of that very awareness. This is essentially wat Sartre later described as the pre-reflective cogito. Kant famously maintained that the 'I think' must be able to accompany all of my representations. Brentano and Sartre maintain that the 'I think' does accompany all of my representings, or better, awarenesses -- it is just that the 'I think' needn't be an act of explicit reflection.
Suppose I see a black cat. The act of visual awareness is typically, even if not always, accompanied by a simultaneous secondary awareness of the primary awareness. I am aware of the cat, but I am also aware of being aware of the cat. How does the Humean account for the awareness of being aware? He can say of the primary straightforward awareness that it is a subjectless awareness of a phenomenal object. But he can't say the same of the secondary awareness. For it is not a phenomenal object over against the awareness of it. It is not something presented but a state of affairs that involves me as subject.
'I am aware of a cat' can perhaps be rewritten subjectlessly as 'There is awareness of a cat.' But 'I am aware of being aware of a cat' cannot be subjectlessly rewritten as 'There is awareness of awareness of a cat.' For the second sentence could be true without the first being true. Suppose there is in Tom visual awareness of a cat, but no awareness of awareness, and in God awareness of Tom's awareness, but no visual awareness of a cat. The point here is that the primary and secondary awarenesses need to form a synchronic unity in one and the same subject.
(2) Why shouldn't we allow that the self might be the kind of thing that "rigorous" examination will tend to obscure. There are lots of things I can perceive, somehow or at some times, but which I can't perceive or can't easily perceive when I "rigorously" consciously attend to them. If I consciously focus my attention on the question of what "truth" means I can easily get confused. I might begin to doubt whether I'm really aware of truth, or the concept of truth. It doesn't follow that I'm not somehow aware of truth at other times, e.g., when wondering whether what X said about Trump is really true.
BV: This is a line of thought worth developing. You mention truth. Time is another example. What is time? Don't ask me, and I know. Ask me, and I don't know. (Augustine). We all have a pre-analytic or pre-theoretical understanding of what time is, but when we attempt an analysis or a theory we get tangled up.
One famous theory of time, McTaggart's, issues in the conclusion that time is unreal. This is the analog of those theories of the self that deny that there is a self. Another famous theory of time, the B-theory of D. H. Mellor and others, denies temporal passage, reducing (real) time to the static ordering of events by the B-relations (earlier than, later than, simultaneous with). This is the analog of theories of the self like that of Hume's that do not outright deny the self, but reduce it to a bundle of impressions or of other items.
You might also develop your thought by exploring the the focus-fringe relation. Focal awareness seems to presuppose fringe awareness. What is on the fringe of my awareness can become my focus, but only if what was before at the focus moves to the fringe. Perhaps the self is like a permanent fringe that cannot be brought into focus, but must be there for anything to be brought into focus. If so, that would explain why one cannot isolate the self as an object among objects. The notion of 'horizon' in Husserl and Heidegger is relevant here.
(3) They don't really justify the assumption that the kind of entity that they claim not to discover in their "rigorous" examination should be identified with the self. Or the characterization is too vague to decide whether we do or don't discover this thing. The vague idea of "an experiencer distinct from the flow of experience", for example. In some sense, I'm pretty sure that I do know this kind of entity from first-hand experience: right now I seem to be aware of the sensations and thoughts I'm having, and also something (i.e., me, my-self) that is the (distinct) subject of these experiences. Presumably they'd say this isn't my experience, or else that they don't mean to deny that I can have that experience but rather some other kind of experience. But then either their position seems false or it's just not clear what they're talking about.
BV: You are putting your finger on an important issue. You can't search for a thing unless you have an idea of what you are searching for. You won't be able to find my lost cygnet unless you know what a cygnet is. One will miss the self -- assuming there is one -- if one searches for it under a description it cannot satisfy. Case in point:
Here are the words of Buddha according to the Anattalakkhana Sutta, his second discourse, the Sermon on the Mark of Not-Self:
The body [rupa], monks, is not self. If the body were the self,
this body would not lend itself to dis-ease. It would be possible
(to say) with regard to the body, 'Let my body be thus. Let my body
be not thus.' But precisely because the body is not self, the body
lends itself to dis-ease. And it is not possible (to say) with
regard to the body, 'Let my body be thus. Let my body not be thus.'
Buddha then goes on to argue similarly with respect to the rest of the five aggregates or categories of personality-constituents (khandhas, Sanskrit: skandhas), namely, feeling (vedana), perception (sanna), consciousness (vinnana), and mental formations (sankharas). All are claimed to be not-self. Thus we are told that feeling afflicts us and is not amenable to our control, whence it is inferred that feeling is not one's self, not one's own inner substance. The tacit premise of this enthymematic argument is that one's self would have to be something over which one would have complete control. The tacit premise is that the self is something wholly active and spontaneous and self-regulating. It is clear that something wholly active will not suffer: to suffer is precisely to be afflicted by something external over which one has no control. To suffer is to be passive. An agent in excelsis is an impassible agent. (In the West, impassibility became one of the divine attributes.)
So if you set the bar really high, it will turn out that nothing we encounter in experience is a self or has self-nature. If so, we should discard, not the self, but the conception no actual self can instantiate.
David Hume too searches for the self under a description it cannot satisfy. You know the famous passage from the Treatise wherein he speaks of entering most intimately into himself only to stumble upon nothing but perceptions. Hume reports, "I never can catch myself at any time without a perception, and never can observe anything but the perception." (Treatise of Human Nature, Selby-Bigge, 1978, p. 252.)
Well, if he is looking for a self that is bare of all perceptions (taking 'perception' broadly to subsume all mental states or conscious experiences), then it is no surprise that he finds nothing. It could be like this: the self is a substance (an endurant, not a perdurant) that remains numerically self-same over time but is always in some state or other. It would then be distinct from each of its states, and from all of them taken collectively, but also necessarily such that it cannot exist without being in some state or other.
And if that is so, then, when I am in a self-presenting state such as that of being euphoric, I am directly aware of my self as being in that state. We may grant Hume that we cannot be aware of the self as an item apart from its states, but that is consistent with being aware of the self in and through its states.
(4) I'd admit that the deep and detailed nature of this (seemingly) distinct entity is mysterious. But then it seems that they're wrongly assuming that having experience or knowledge of X requires having experience or knowledge of X sufficient for some kind of exhaustive and perfect understanding of X. I know about other people, and I experience them, without knowing everything about them (or what the ultimate nature of a person is, etc). Harris seems to be saying merely that the precise character of his self is elusive, hard to individuate or define, at least while he's meditating. I don't understand why that phenomenological fact is supposed to warrant the conclusion that he's found nothing of the kind. Maybe I haven't meditated properly but, in my experience, I take myself to be always dimly aware of just that kind of thing. But it's in the corner of the mind's eye, so to speak.
I agree that the self is mysterious and indeed beyond the reach of naturalistic understanding.