We don’t know yet, and maybe it’s unknowable.

Believing everything can be explained that way is itself just another ideology followed blindly

The way I've been thinking about it is not that internal experience is unfalsifiable, along with the modern science connotation that everything that is unfalsifiable is automatically irrelevant (which would be quite absurd, as everything that is dear and meaningful to humans are all simply cognitive phenomena in the end!). It's that it is externally, naively and a-priori unfalsifiable. That is, you can't externally measure or prove it, without having an a-priori theory of what it is and how it happens in the first place. But it is internally falsifiable, in the sense that if we have it, then we know we have it. Note that it's not that "If I have it, then I say I have it", or that "I one has it, he says he has it"; those are all communication to the external world, and for example machines can clearly say they have it without having it, or you can have it before even learning the words that represent it. But if you have it, you can know you do. This actually creates some potential for expanding this knowledge, maybe, in the future, to allow for external verification. We can internally investigate properties associated with consciousness, and from those properties (along with scientific knowledge), maybe one day we will know more about the objective basis which affords consciousness/sentience manifesting or emerging. So I see it like an experimental field where the component of self-assessment or self-experimentation or self-measurement is essential (again along with more conventional scientific notions).

I have been thinking the same way about all properties of life/consciousness, in particular if we think of ethics as a property of (even if you consider the ethics or ideals only pertaining to how it would be ideal to lead your own life) the mind, or of sentience in general. I think of ethics as an inherent property of existence: it stems from the fact that internal experiences/internal life/sentience/etc. are the only thing that could have value, that in fact sentience is experimentally (again taking the point of view of experimental sentience) the only thing that truly matters or has value. If we are minds, we know that only the content of minds can matter; it cannot matter, for example, that a lone rock in some place no one can know about has this or that fate, because there is no mind to interact or perceive and be affected in any way by it. So all of ethics can probably be founded or based upon this kind of observation, and the act of experimental self-observation of consciousness. And I think it's quite important that we collectively recognize those values and what matters to make our lives better (better yet, as good as it can be!) :)

sorry the brain is a tool to who exactly in this ostensibly reductive worldview?