We don't get to see, directly, how everyone else experiences life. They might tell us, and they might do so more or less truthfully and accurately. They might struggle to communicate those things in a way we really understand. Meanwhile, we ourselves may struggle to explain our experiences and perspectives to others, or be ashamed or embarrassed about doing so.
One aim of literature and poetry is (or may be) to open up that inner world—to do a better job of expressing those experiences than most folks manage to, to do so across a breadth of experience we may not all encounter, and to make explicit and examinable things we may not ourselves think to examine, or may otherwise think shameful or private and ours alone.
Like, say, the experience of taking a drug and not feeling at all like you changed, but that the world did, as in the original example.
The practical utility of this in communication is evident in that the well-read tend to reach for episodes from literature or passages of poetry to relate difficult concepts concerning that inner life, and this practice is in fact helpful to readers who have a similar background, or, if you will, a common language (as in the section of my post that you quoted). This is seen extensively in philosophy, for example, and is so helpful in religion that even those that try to downplay literature or scripture (Buddhism, for example) tend to end up with extensive literatures regardless, because they are so useful for relating difficult, very personal ideas and experiences, even if they can only ever be the "finger that points" and never directly the thing-in-itself. For the individual per se it can help us understand ourselves, help us feel less alone, act as a kind of therapy to some degree, be one factor in working out what exactly we're doing here, what we want or ought to be doing, expand or exercise our empathy, and provide ethical and moral guideposts more effectively than any kind of "do this, don't do that" list of bullet points.
One aim of literature and poetry is (or may be) to open up that inner world—to do a better job of expressing those experiences than most folks manage to, to do so across a breadth of experience we may not all encounter, and to make explicit and examinable things we may not ourselves think to examine, or may otherwise think shameful or private and ours alone.
Like, say, the experience of taking a drug and not feeling at all like you changed, but that the world did, as in the original example.
The practical utility of this in communication is evident in that the well-read tend to reach for episodes from literature or passages of poetry to relate difficult concepts concerning that inner life, and this practice is in fact helpful to readers who have a similar background, or, if you will, a common language (as in the section of my post that you quoted). This is seen extensively in philosophy, for example, and is so helpful in religion that even those that try to downplay literature or scripture (Buddhism, for example) tend to end up with extensive literatures regardless, because they are so useful for relating difficult, very personal ideas and experiences, even if they can only ever be the "finger that points" and never directly the thing-in-itself. For the individual per se it can help us understand ourselves, help us feel less alone, act as a kind of therapy to some degree, be one factor in working out what exactly we're doing here, what we want or ought to be doing, expand or exercise our empathy, and provide ethical and moral guideposts more effectively than any kind of "do this, don't do that" list of bullet points.