I read that one. It might have been Shadows of the Empire, but don’t quote me on that. The gist of the scene was that when Vader sat and brooded over his injuries and the injustice of his situation (in his opinion), hatred overtook him, the Dark Side filled him, and he was able to breath without mechanical assistance. The problem is that no one can stay mad 24/7, so Vader couldn’t eliminate his need for the breathing mask. Plus, as we know, Vader was never able to completely give himself over to the Dark Side like Palpatine did.
BTW, Yoda was 900 years old when he died. AFAIK, they’ve never said what species he was. The novels seem to treat it as a mystery, and imply that Yoda never told anyone what type of being he was.
Why must they exist? Maybe the Force doesn’t go around handing out bodies twice?
“You’ve gone and broken your spine mister! Well, you’re just going to have to deal with it because we’re not buying you another one!”
The Emperor didn’t allow stem cell research. 
Well, let’s say you’re an adult Jedi and you get your hand chopped off.
Now, you have two options. Option One is to get a cloned limb. Now, you don’t already have a spare-parts bin of cloned limbs back at the barracks, so they’ll have to take a tissue sample and grow a new one. It’s already been established that cloning humans is a years-long process, and while they can accelerate the growth, it still takes quite a while for a clone to reach adulthood. So, you get to clomp around for upwards of what, five years maybe, without a hand? By the time they get around to grafting it to your stump, your nerves and blood vessels would have atrophied horribly, so the grafting surgery, even if it were possible, would probably be prolonged and hideous. Then, you have a hand, but how useful would it be, really? After years without a hand, would your reflexes be the same? Would the cloned limb be up to the stresses you’d likely place on it?
Option 2 is getting a robotic limb. They’re pretty darn common, apparently, so one can be attached right away. A robotic limb can replicate full speed and function, and, if TESB and ROTJ can be believed, a robotic hand even has pain sensation. By the time of TESB, they can even make limbs that look 100% natural.
So, really, which way would you go?
I’ve wondered about that at times as well. The non-SF reason is that for the movie special effects it was cooler to show a robotic hand in the final scenes. It’s the same reason the galaxy in the background is visibly turning, whereas by comparison, our Milky Way galaxy rotates about once every 250 million years. (Or 200 million years – cite – Monty Python’s ‘The Galaxy Song’ 
) Definitely not fast enough for a special effects effect.
I figure that advances in medicine should eventually allow for regeneration or limb regrowth. In E.E. ‘Doc’ Smith’s Lensman series, in one of the books they developed a process that re-grew all injured/lost limbs. The process was hurried-up to help out the Hero who had a bad run-in with the Bad-guys. I figured that any woman being given this procedure would probably grow back her hymen and as a hormone-ridden teen (when I first read the series) I wondered if this would be a good or bad side effect? If you had regeneration technology, I suppose you would also grow back any removed appendix, tonsils, vasectomy snipping, etc. Such a process could result in all sorts of unintended consequences.
I was sort of frustrated by there being a second Yodanimal on the Jedi council. I think it was more fun with just one Yoda.
The idea of Yoda being unique didn’t make much sense though. It’s a galaxy with millions of inhabited worlds and countless alien races; who *cares * what Yoda is?
There was another Jedi of Yoda’s species, a female on the Council, in TPM-Yaddle. In the novels, Yaddle is said to be about 475 years old.
I realize you’re joking here, but you’re probably a lot closer to the truth than you think: They can’t regenerate limbs because if they could, then Darth Vader wouldn’t have cut his son’s hand off so that he would be more like dear old dad… same sort of reason why they don’t put seatbelts on the Enterprise (if they did, then people wouldn’t fall out of their seats…).
Another possible reason: In Eps 1-3, the galaxy is at its pinnacle of peace and, one would assume, technology. It is obviously beginning to slide into chaos and warfare but we can see that the clone armies are, from a contemporary viewpoint, the be-all and end-all of technological spiffiness. And the Republic holds the reins to this neat stuff.
Contrast this with Eps 4-6. The war has raged for I don’t know how many years. The Republic has morphed into the Imperial Empire. One can assume that the thousands of member systems of the Empire have transitioned their economies into war economies. The rebels are battling from no fixed base, with unseen (and presumably limited) economic support, using older fighters while handing out titles like “General” to any old two-bit Corellian smuggler. It’s not implausible that the rebels simply couldn’t get their hands on the technology (pun not intended, but what the hell, I’ll let it stand) to clone a hand or other body part.
Also, the casualties in the battles that we’ve seen tend to be either (a) space flotsam, blasted into a million tiny pieces, (b) poor bastards with a zillion volts of Seventies-style death rays sent through them, or © thousand-year-old Sarlacc cud. Limb replacement simply might not have been the highest of medical priorities at the time.
So I guess the answer is because it’s more “dramatic”, plotwise to not be able to have such basic technology, and there’s not necessarily any logic behind it. I hate when that happens.
Consider this: Luke can use telekinesis to move objects right? He could have carried his hand with him and have it re-attached when he reached safety…
Also, it wouldn’t take years to regenerate a limb. How long does it take a frog? A frog would be at a serious disadvantage if it took 5 years to regrow a limb!
I can imagine a situation where you would have an artificial hand covering your regenerating limb while you continue to roam around the galaxy.
Anyway, I asked this question, because it seems to be a simple thing for a technologically advanced civilization to do. After all, we seem to be close:
http://wired-vig.wired.com/wired/archive/11.11/regeneration.html
I predict that we’ll have some increased regeneration capabilities within 100 years.
And for those who think that regeneration necessarily equals increased cancer, you’re wrong, as you will find if you read the above article.
In fairness to Luke on that, I think it would be a bit hard to concentrate on keeping your severed hand nearby when (a)it was just severed, (b)you’re in the middle of a duel, and ©you’re about to experience some extreme parental trauma. The hand plunged down a shaft and out of sight, he couldn’t have saved it to be reattached.
He could have retrieved it telekinetically and used it to whack Vader with: “Hey, Dad! Need a hand? {Slap!} Let’s have a big hand for the Dark Side! {Thwap!} Talk to the hand! {Pwap!}”
Yeah, but how long does it take a frog to grow a whole frog? Humans develop a lot slower than other animals (even compared to animals our size), so it’s entirely reasonable to suppose that human organs and limbs would also take longer to develop, if the technology even existed in the first place.
And it’s not an implausible state of technology. We right now have the technology to clone humans, but we do not have nor anticipate any time soon the technology to regenerate human body parts. The closest we could come right now would be to produce a whole clone (which would, incidentally, be a separate human being who might possibly not approve of the procedure), let the clone grow to maturity, and then lop off one of the clone’s limbs to graft onto the victim’s body.
The bit about regen possibly raising the risk of cancer was only speculation, and we can’t say anything definitive about it until we have the technology to actually try it. But we can say that, with current technology, clones age (as in, become geriatric) much quicker than normal organisms. It’s quite possible that a regrown limb might end up withered and weak far before the rest of the body.
I thought I remembered reading somewhere—like a semi-canon New Essential Guide to Characters, but it might just have been fan speculation—that the fact that Vader couldn’t turn himself fully to the Dark Side prevented him from healing himself. He would have been able to do it if he could give himself over to pure hatred.
I also seem to recall hearing about “Jedi Healers” in recent months, as well. (In a novel set in the Clone Wars, or something.) I don’t know if they were just Jedi with medical or surgical skill, or if they just Jesused-away injuries using the force, or what. And I don’t know if they could have healed someone as in tune with the Dark Side as Vader, even if any were left alive after the (I presume) Jedi purge after Palpatine took over.
About reattachment: I don’t see reattachment as a possibility when a limb is severed by a lightsaber. We’ve seen it happen twice, right? (okay, three times if you count the anomalous bloody severing by Kenobi in the cantina in ANH) It appears, when a limb gets cut off by a lightsaber, that the wound is instantly cauterized. I’d imagine that one or two inches of flesh and bone are instantly vaporized in the bargain, as well. Can you imagine reattaching a limb from which a chunk is missing? Assuming you could even get the nerves and blood vessels to match up, one arm would be significantly shorter than the other!
I’d still go with the robot hand, by a mile.
Four times, I think. Bounty hunter Zam Wessel in AOTC. Don’t remember the amount of blood, though.
If I may…The Chopped-Off Hands of Star Wars.
In one of the references for the extended universe books, it seems that at least one person with a light-saber-severed arm does indeed get it replaced with a cloned arm. (Though, having not read the book myself, I suppose it’s possible she had the arm of a clone—like some hapless shmuck stormtrooper—grafted on; or a robot arm built by a guy named Clone, or something. )
Exactly! It’s in the George Lucas Big Book of Screenwriting right next to “Choosing a Planet with a Suitably Extreme Climate” and “Cavernous Abysses and Who to Drop Down Them.”