It seems to me that in temperament, Tolkien was analytical. He spent much of his life in the search for meaning in human affairs, which meant that he was particularly good at pattern recognition and identifying what was ironic and absurd in the things that he encountered. It should therefore be no surprise that much of his comedy relies on absurdity, incongruity and false patterning. This manifests itself in a number of easily recognisable strands: punning and wordplay, deliberate incongruity, subversion of expected or established order and irony, particularly in juxtaposing reader and character knowledge.
The punning and wordplay are perhaps the easiest elements to look for. I've already posted elsewhere an incident reported by Warren Lewis, in which Tolkien greeted some deer encountered on a night walk through the grounds of Magdalen College by the doffing of his hat accompanied with "Hail, fallow, well met". In a more cerebral joke, we see in the Etymologies (HME 5) under
THÔN that
Taur-na-Fuin ('Forest under night') is a multi-linguistic pun on
Dor-na-Thuin (Ilkorin form of
Dorthonion -'Land of Pines'). In a more general piece of word-play, Tolkien spends several paragraphs early in
The Hobbit having Gandalf pull to pieces Bilbo's uses of "Good morning"; in LR at the Gate of Moria, Gandalf becomes the victim of his own cunning by confusing 'say' and 'speak'. Bilbo tells the three trolls that "I am a good cook myself, and I cook better than I cook, if you see what I mean."
This sort of play around the complexities of language is probably to be expected in someone who spent most of his life studying them, and one can scarcely study language without spending some time observing people. The part of Tolkien's life that Philip and Carol Zuleski describe as "academic busywork" (committees, boards and other meetings) and his tutoring of students would have given him ample opportunities for observing the absurdities of which even the most intelligent people are capable. Gandalf's riposte to Saruman in
The Hunt for the Ring using only smoke-rings, while not technically a joke, is born of this sort of observation.
The pointing out of social absurdities, particularly to deflate the pompous, is a strand of Tolkienian humour that comes out throughout
The Hobbit and LR. The self-important Master of the Houses of Healing is outdone in his job by a gossippy and uneducated orderly, leading Gandalf (again) to declare "...find some old man of less lore and more wisdom who keeps some [kingsfoil] in his house!" and Aragorn to inform him that "I care not whether you say
asëa aranion or
kingsfoil, so long as you have some." Although again, not primarily a comic scene, Tolkien demonstrates the idiocy of knowledge without understanding and the superiority of practical over theoretical knowledge. In the same vein, we are reminded by the narrator of
The Hobbit that Bilbo "...had read of a good many things that he had never seen or done"
Thorin Oakenshield is a repeated target of Tolkien's absurdist deflations. At his first appearance in
The Hobbit he is squashed beneath Bombur, who,
we are repeatedly reminded, is no small weight to bear. He is the first to be retrieved from his barrel after the escape from the Elven-king's halls, and his bedraggled appearance receives most of the narrator's attention. Tolkien very much admired the heroic, but could not resist a poke at convention or pomposity where possible.
Obviously
Farmer Giles is in its entirety a subversion of the heroic mode and an attack on those who fail in their duty while adhering to its conventions: Aegidius de Hammo is the least heroic character one can imagine, and yet he succeeds where all the knights whose business it is to defend the kingdom have failed. The most effective weapon against Chrysophylax has been handed out as a throwaway gift to a relative nobody (one of Pauline Baynes' illustrations shows Caudimordax hanging on a wall with a spider weaving its web near the sword's point), and the hunting of dragons has been abandoned so as not to offend the palace cook. These are absurdities, but they are easily recognisable in real-world society. Convention and tradition are rich wells of absurdist comedy.
However, this leads me to the very reason for the lack of humour in
The Silmarillion. While Tolkien continues to make use of dramatic irony, he does not poke fun at characters such as Fëanor or Thingol, and I think that this has the same source as his very overt parody of characters like Augustus Bonifacius. Tolkien believed in the value of heroic ideals. He thought that they were important and not innately comic. What struck him as funny was when those whose job it is to be heroic, or to possess knowledge, or to bake the Great Cake, were not very good at it; or when people unsuited for heroism were forced into heroic situations. Essentially the humour derives from our recognition of the difference between the actions of characters and the narrative convention in which they appear or, to put it another way, the recognition that people in the real world rarely live up to ideals. The ideal itself was out of bounds for humour, and I think the omission of mock-heroism from the Silmarillion over time was precisely because mock heroism opens the door for mockery of the heroic mode itself. Humour was not appropriate to the tone that Tolkien eventually decided to set for his longest-running project.
In a similar vein, in
On Fairy-stories Tolkien makes a reference to fellow don Lewis Carroll (he also alludes to his poem
Jabberwocky in
The Monsters and the Critics): "...creative fantasy is founded upon the hard recognition that things are so in the world as it appears under the sun... So upon logic was founded the nonsense that displays itself in the world of Lewis Carroll."
I think that something similar could be said of Tolkien's use of humour. It is, like much humour, essentially subversive; but in a pun is contained the recognition that the obvious pattern of meaning is superficial. In deliberate absurdity is encoded the recognition of proportion and reason, and in the mock-heroic, at least as written by Tolkien, is planted the recognition that the heroic is real, desirable, noble. If he points out where people often fall short of the ideal it is because he wishes them to improve. So Giles rises in his own unheroic way to become a king, Bilbo, by an unconventional path, becomes a legitimate hero, but the heroic ideal as personified in, say, Aragorn, is never in question. The Silmarillion is not a social convention of the ideal, but the thing itself and there is no room in it for the author to poke fun at his narrative mode. We can, Milan Kundera tells us, move from the light to the serious, but to attempt the opposite seldom works.
In my opinion, Tolkien in life would have been a far better source of laughter than he is in writing, but if you choose to read
The Silmarillion hoping to roll about the aisles, I would respectfully submit that you have chosen poorly.