This thread has led me to consider a new method of analysis to determine how likely a speculation or supposition is.
Someone has probably pointed out this method before, but for now, I am going to call it 'Flammifer's test':
"If a supposition creates more new issues and problems than it solves, then it is not a good supposition."
In this case, The Supposition tries to solve what JRRT means when he has Gandalf say that he hopes the Nazgul, "were scattered, and have been obliged to return as best they could to their Master in Mordor, empty and shapeless."
No one in this thread has yet pointed out that this is an expression of hope by Gandalf, rather than an expression of fact. (Which, I think, is relevant.) Still, The Supposition, is trying to solve the problem of what is meant by obliged, empty, and shapeless.
At first glance The Supposition offers an interesting explanation of these words. However, with further thought, The Supposition raises more and more issues and problems:
How is Sauron's 'boost' removed from the Nazgul in the flood? If removed by the power of Gandalf and/or Elrond, why are there not other instances of using this to defeat the Nazgul? How does Sauron 'boost' corporality? Does he do this in other instances? Why not? If the 'boost' is removed in the flood, how do in-corporeal Nazgul travel back to Mordor? How can incorporeal beings travel at all? If they can travel instantly or swiftly, why no spies near Rivendell when the Company sets out? If they cannot travel, how do they come to appear again on winged beasts? If they can travel incorporeally, why do they need winged beasts at all? For most 'black breath' missions in the war, corporality would seem unnecessary?
I'm sure there are other issues and problems which arise under the conditions of The Supposition. So, I propose that The Supposition fails the rule of 'Flammifer's test'.
What do you think of the rule? (I'm sure that it already exists, and has a name. Does anyone know what that might be? It is similar, though perhaps not quite the same, as Occam's razor?)
Do you think the rule applies well in this case?