“Nobody has ever used DVDs or “manuals” to learn how to play soccer, football, baseball, etc.”
Different skill set, but you are incorrect. Many such manuals exist. I learned many tricks about soccer from reading, such as how to properly catch a ball as it is falling. You then translate that into the practice you mentioned. You have to learn what to practice before you can actually practice.
“Unless you’ve put in hours of very specific practice, i.e. unless you’ve had thousands of balls-to-the-wall training sessions with partners yielding rubber knives with similar weight/length/feel to other knives, you cannot call yourself a good knife-fighter.”
There is no substitute for using a real knife. People who do not tend to lose inhibitions. For instance, one of the most thrilling and frightening experiences I had with knives involved sprinting while holding my knife in a ready position. It’s a really fast sprint, leaning forward in case a quick duck of the head is required. As you come to the target, you swing the blade, and you learn to keep your balance…but there is always that bit in the back of the mind saying “You know, if you fall, you’re going to stab your leg or bicep. Don’t fall, genius.” Also, for knife-fighting, you really don’t need a partner unless you want to practice cutting at someone’s arm while they swing at you, which is not necessary since no one is going to swing an arm at someone with a knife.
“I’m always very skeptical about these people who claim to be great knife fighters or that they’re able to disarm someone yielding a knife or gun relatively easily for precisely this reason. Many karatekas, aikidokas, and so forth perform their cute little katas and then they think they know something about actual fighting.”
Disarming a knife is nonsense. I can’t agree more. Any idiot that is going to get close quarters with someone holding a blade, whether by design or accident, and attempt to take the knife away deserves a diced palm. Just getting control of the arm puts you in the blade path. Panic mode is the best way to deal with being jumped by someone with a knife.
A gun can be disarmed easily once you have your hand on the gun itself. The problem is that index fingers and bullets both move faster. If you think you can get away with your life, hand over your watch. If they are going to shoot you one way or another, then you really better hope beyond hope that they have a gun right in your face and told you to put your hands up, because that’s the only way you can possibly move your head and grab a gun before they reposition, fire, and end you. Also, if they fire while you’re holding the gun, you can still disarm it, but the recoil and the snap of the chamber are enough to shock most people into letting go. I would recommend not fighting someone with a gun, unless you have a gun.
And don’t even get me started on Aikido people. They think they’re invincible until you start throwing jabs at them. Then they suddenly act as if they’ve never seen a fight in their lives…
“In order to get good at a specific skill, you need hours of specific practice.”
Lots. This is the best advice in the universe about anything, ever.
“And of course, there are the people who study books and/or DVDs and then call friends over to “practice.” These people often ruin their potential martial arts/combat sports careers by not having someone qualified oversee them.”
You can learn how to throw a kick by reading, studying some diagrams, and then practicing. Wouldn’t recommend trying to learn judo that way, unless you’ve got a lot of time to kill for no good reason. But I doubt anyone really needs someone to oversee them in any way other than something like a spotter for practicing backward handsprings. Broken necks are even less fun if no one’s around to call you an ambulance.
Overall, I’d say reading has its place in learning how to fight, just as it has a place in learning anything. The practice is, however, the key.