How we cite our quotes: (Book.Chapter.Paragraph)
Quote #7
But they were at a disadvantage: they started afraid—afraid of Ambrosius' reputation, of his recent ferocious victory at Doward, and more than both […] of my prophecy to Vortigern. […] And of course the omens worked the other way for Ambrosius. (IV.4.5)
Merlin's very perceptive here about the power of prophecy. On the winning side (Ambrosius and Uther), it gives the soldiers a boost. But for the losers (Hengist and the Saxons), it makes every effort literally an uphill battle. Same prophecy, two different realities. There's also the sense that Team Hengist has a lot of angst because they know that Ambrosius will stop at nothing to restore Britain to the Britons. These two sides are not entering the fight in the same frame of mind.
Quote #8
I went wakeful, as one is at a death-bed, and on that voyage of all those in my life, I never felt the movement of the sea, but sat (they tell me) calm and silent, as if in my chair at home. […] I suppose I was not there. I was watching still between day and night in the great bedchamber at Winchester. (IV.10.43)
Merlin is experiencing a phenomenon called bilocation, where his body is in two places at one time. It's not clear whether he's physically at Ambrosius' deathbed here, or whether he's just there "in spirit." But he does manage to experience both the journey from Ireland and the death of his father simultaneously. It's definitely an altered state of reality, and it's not something that Merlin fully understands.
Quote #9
I heard it said, long afterwards, that I moved the stones of the Dance with magic and with music. I suppose you might say that both are true. I have thought, since, that this must have been how the story started that Phoebus Apollo built music the walls of Troy. But the magic and the music that moved the Giants' Dance, I shared with the blind singer of Kerrec. (V.1.5)
Any rock star would understand the phenomenon described here by Merlin. You do one good (or crazy) deed, and the whole internet goes wild. In Merlin's day, songs and stories passed by performance were the internet. And you can imagine how much fun those Dark Age folks had with the story of how Merlin moved gigantic, supernatural stones. There's no way that a scientific explanation was ever gonna make it into those verses.