Like Gieseking playing Scarlatti; (6)
Both of these men are geniuses in their own right: Scarlatti at composing, Gieseking at performing. Moore uses them as examples of truly knowledgeable and creative minds. So when the mind is at its best, it sounds an awful lot like this dynamic duo.
[…] the mind
feeling its way as though blind,
walks along with its eyes to the ground. (10-12)
This image illustrates the mind's constant, even involuntary quest for knowledge. It's always on the prowl, even when it can't quite see what it's prowling for.
because trued by regnant certainty, (18)
In other words, the mind is always set straight by the dominating force of certainty. As opposed to, say, emotions, which are more likely to fluctuate and be uncertain. The mind knows what it's doing. So trust it, Shmoopers.