This question about Bilbo understanding the spiders after he wore the Ring in Mirkwood, got me wondering. Were the spiders really rational beings? If they could talk with purpose and in a meaningful manner I would tend to think so.
The same goes for the Eagles which several times intervened, eg saving survivors during the fall of Gondolin, rescuing Gandalf and then Frodo and Sam. Were they actually rational beings?
Did Tolkien discuss this issue at all?
Bilbo (wearing the ring) was able to understand the spider's speech.
Their voices were a sort of thin creaking and hissing, but he could make out many of the words that they said. They were talking about the dwarves! "It was a sharp struggle, but worth it," said one. "What nasty thick skins they have to be sure, but I'll wager there is good juice inside." "Aye, they'll make fine eating, when they've hung a bit," said another. "Don't hang 'em too long," said a third. "They're not as fat as they might be. Been feeding none too well of late, I should guess." "Kill'em, I say," hissed a fourth; "kill 'em now and hang 'em dead for a while." "They're dead now, I'll warrant," said the first. "That they are not. I saw one a-struggling just now. Just coming round again, I should say, after a bee-autiful sleep. I'll show you." With that one of the fat spiders ran along a rope, till it came to a dozen bundles hanging in a row from a high branch.
The Hobbit - Chapter 8: Flies and Spiders
The Lord of Eagles spoke to himself and a normal eagle spoke to Bilbo (without the ring on)
"What's all this uproar in the forest tonight?" said the Lord of the Eagles. He was sitting, black in the moonlight, on the top of a lonely pinnacle of rock at the eastern edge of the mountains. "I hear wolves' voices! Are the goblins at mischief in the woods?"
...
O no! Not a bit like storks-forks, I mean," said Bilbo sitting up and looking anxiously at the eagle who was perched close by. He wondered what other nonsense he had been saying, and if the eagle would think it rude. You ought not to be rude to an eagle, when you are only the size of a hobbit, and are up in his eyrie at night! The eagle only sharpened his beak on a stone and trimmed his feathers and took no notice. Soon another eagle flew up. "The Lord of the Eagles bids you to bring your prisoners to the Great Shelf," he cried and was off again.
The Hobbit - Chapter 6: Out of the Frying-Pan into the Fire
Foxes
A fox passing through the wood on business of his own stopped several minutes and sniffed.
'Hobbits!' he thought. 'Well, what next? I have heard of strange doings in this land, but I have seldom heard of a hobbit sleeping out of doors under a tree. Three of them! There's something mighty queer behind this.' He was quite right, but he never found out any more about it.The Fellowship of the Ring: Chapter 3 - Three is Company
Thrushes
He started-but it was only an old thrush. Unafraid it perched by his ear and it brought him news. Marvelling he found he could understand its tongue, for he was of the race of Dale. "Wait! Wait!" it said to him. "The moon is rising. Look for the hollow of the left breast as he flies and turns above you!"
The Hobbit - Chapter 14: Fire and Water
Eagles yes, spiders maybe.
Tolkien considered the possibility of mere 'beasts' possessing articulate speech — an essay in Morgoth's Ring says the Orcs were such:
In summary: I think it must be assumed that 'talking' is not necessarily the sign of the possession of a 'rational soul' or fëa. The Orcs were beasts of humanized shape (to mock Men and Elves) deliberately perverted / converted into a more close resemblance to Men.
Though this essay isn't really compatible with the published 'canon' it does show that Tolkien considered the possibility of nonrational creatures speaking, and also that fëa is equivalent to the concept of 'rational soul' in our-world theology/philosophy.
Also from a letter (no. 153, but quoted in Morgoth's Ring) Tolkien said:
I am not sure about Trolls. I think they are mere 'counterfeits' [...] Of course... when you make Trolls speak you are giving them a power, which in our world (probably) connotes the possession of a 'soul'.
Therefore we can say that anything with a fëa is rational.
The Great Eagles are "spirits from afar" inhabiting animal bodies, sent (along with the spirits that became Ents) apparently by Eru as a result of Yavanna's discussion with Manwë about protecting nature. (This is described in "Of Aulë and Yavanna," Ch. 2 of The Silmarillion.) They're probably closer in nature to Gandalf or Saruman than normal birds.
The Spiders of Mirkwood are not natural spiders, and not just in size: they are descendants of Shelob:
her lesser broods, bastards of the miserable mates, her own offspring, that she slew, spread from glen to glen, from the Ephel Dúath to the eastern hills, to Dol Guldur and the fastnesses of Mirkwood.
And as Shelob is the "last child of Ungoliant to trouble the unhappy world", and Ungoliant was probably one of the Ainur and definitely a very powerful evil spirit, there is a 'supernatural' or 'spiritual' strain in the spiders of Mirkwood.
Whether they're completely rational in the sense that humans (and Elves, Dwarves etc.) are is probably unanswerable — Tolkien's notes on this sort of thing in History of Middle-Earth Vol. X Morgoth's Ring are inconclusive/somewhat undecided as to whether speaking actually implies possession of a fëa or rational soul — but smarter than ordinary spiders, for sure.
Wow. There are some really great answers here, such that I hardly think mine will have any impact, or seem of any real relevance...
My thinking on the topic was that 'the more rational the creature, the more aware they are of their surrounds, the events in their surrounds and the relevance of these events.' What I mean by that is, the eagles are rational beings and so they can see the strife in the world and the struggle between 'Good and Evil.' As a result, they are both willingly and unanimously 'Servants of Manwe' in this struggle.
If the eagles were not rational, then such servitude might be seen/ thought of as slavery and would not have been employed by the Valar. And so, in this case, it is precisely because they are rational/ sentient beings that they are able to be 'Servants of Manwe.' Much the same way as the Vanyar are unanimous and willing servants of both Manwe and the rest of the Valar (Melkor excepted), while- for example- plants, even trees that only exist in Valinor, cannot be seen to be nor said to be servants of the Valar, even though their very act of existence is an act of obedience to the will of Yavanna...
So to summarise, I think that those beings who willingly align themselves with others, be they Good or Evil, they MUST have the intellectual capacity to understand certain aspects of existence and thus are identifiably 'Rational/ Sentient.' Those eagles who serve Manwe are thus rational beings. The spiders of Mirkwood, who apparently serve the 'Necromancer of Dol Guldor,' are thus also rational. The orcs and dragons who serve Morgoth and later Sauron, are rational. And so forth and so on...
