How we cite our quotes: (Paragraph)
Quote #1
I was sick, sick unto death, with that long agony, and when they at length unbound me, and I was permitted to sit, I felt that my senses were leaving me. (1)
From the very beginning, we know that the narrator is in a sort of in-between state, moving back and forth between consciousness and unconsciousness, between life and the edge of death.
Quote #2
I had swooned; but still will not say that all of consciousness was lost. What of it there remained I will not attempt to define, or even to describe; yet all was not lost. In the deepest slumber – no! In delirium – no! In a swoon – no! In death – no! Even in the grave all was not lost. Else there is no immortality for man. (3)
Here, our narrator seems to argue for the persistence of some kind of consciousness, even at the point of death, although he's reluctant to define what exactly it is. Still, he argues that if consciousness didn't continue in death, there could be no immortality, no afterlife. At the very least, we know that our narrator, a heretic of some sort (why else would he be imprisoned by the Inquisition?), still believes in life after death.
Quote #3
Arousing from the most profound of slumbers, we break the gossamer web of some dream. Yet in a second afterwards (so frail may that web have been) we remember not that we have dreamed. In the return to life from the swoon there are two stages; first, that of the sense of mental or spiritual; secondly, that of the sense of physical existence. It seems probable that if, upon reaching the second stage, we could recall the impressions of the first, we should find these impressions eloquent in memories of the gulf beyond. And that gulf is, what? How at least shall we distinguish its shadows from those of the tomb? But if the impressions of what I have termed the first stage are not at will recalled, yet, after long interval, do they not come unbidden, while we marvel whence they come? He who has never swooned is not he who finds strange palaces and wildly familiar faces in coals that glow; is not he who beholds floating in mid-air the sad visions that the many may not view; is not he who ponders over the perfume of some novel flower; is not he whose brain grows bewildered with the meaning of some musical cadence which has never before arrested his attention. (3)
This is quite the philosophical musing from our narrator. It's a complicated and, as you can see, rather long thought, but you can break it down. Let's give it a shot! So, according to the narrator, when we awake from "the most profound of slumbers" (like, say, fainting and seeing hallucinations), we break a kind of dream barrier. What we mean is, whatever it is that we experienced in that "swoon" is separated by the thinnest of membranes. This awakening, though, has two stages. In the first, we return to mental and spiritual life; in the second, we recover our physical senses. In the narrator's opinion, in that first awakening, our minds are still filled with memories of the beyond, that swooning dream state. Unfortunately, it's hard to remember those things; it's difficult to even understand what separates us from that swooning state. For all we know, he says, that "gulf" could be just like the gulf of death.