You only understand the instructions because you have experience with the tools. Do you know how many people that don't know what a Philips head screwdriver is? Why... Because they've never used the tools. You have experience, which allowed you to "understand" the instructions. Without that experience, you wouldn't have known what any of those tools where. That being said, changing an alternator is as easy as changing a spark plug or a headlight. There are a couple of bolts, a few wires, and a belt to tension. That isn't a leap in mechanics knowledge or logic if you have already changed your oil.
Who would you rather perform an appendectomy (appendix removal)
The guys that has never held a scalpel, but has a manual
or the guy that has been a surgeon for 10 yrs and doesn't have one?
And lastly, why is experience required for a job even if someone has a degree in said field?
That doesn't even make sense. How does experience without information teach me what a screwdriver is or how it's supposed to be used? With enough trial and error, you could probably figure that out because it is a simple tool. There's only so much you can do with it. But anyone can figure out a screwdriver. You don't have to know the name. Instructions often show a view of the screwdriver head to show what kind to use. Even if it doesn't, it is still about knowledge. Are you going to build a car just by trial and error? Of course not. Can you build one with instruction and study? Yes, though it does require a lot of instruction and study. Practice building a car might improve your speed in building it and memorization might make it easier to not have to keep looking at instructions, but you're not going to create a better or different car by building the same car over and over. You can try different things, but LBD isn't about trying different things. It's about doing the exact same thing repeatedly. If I build a bicycle 1000 times, I can't suddenly build a minibike.
And your surgeon one is absolutely a bad example. I would choose the person with instruction in how to do something and training in it by a qualified professional even if they have never held a scalpel than a person who doesn't know what they are doing and just figures it out on their own as they go. The first is an example of someone who knows how to do what needs done, while the second is what you'd see in some third world country where you're just as likely to be killed than survive regardless of years doing it. I certainly would never trust a surgeon who has no idea what things are or why they work the way they work and who just does what they think is best. Besides, anyone who is a surgeon will have been taught by others and will have read and studied. They wouldn't be surgeons in a vacuum where everything they know is from cutting people open over and over until they figure it out.
Jobs ask for experience more often because they want to know you have training and not just a degree that may not be from a good school. But jobs also often accept people with a degree from a good school even without experience because they know the school taught them well. Quality of education varies greatly. Some give you very little actual skills and just provide knowledge. Others provide you with skills and knowledge both. Since employers often don't know how good your particular school was, they lean toward experience and then they contact your previous employers to find out if you actually knew what you were doing. They don't just accept that you've done X years of work in something because that doesn't mean much. They check with your previous employer to find out how well you did that work and how much you know of it. They can't contact schools (in most cases) to check how well you learned there, so again it is easier to lean into experience, which they can verify. Besides, you can easily turn that around... why do employers care if you have a degree if you have a decade of experience? It's because they want to make sure you understand what you're doing and not just "winging it."
But unspecified jobs are not a good example because what you can or can't do based on learning versus practice varies. You can make music without any training because that is about what sounds good to you and you can hear the notes from other music and just need to learn to play by ear (you hear it and find the notes that sound the same). If you understand something is an instrument, playing it isn't difficult to figure out. Especially considering most people have seen most of the common instruments being played, so already have the knowledge of what needs to be done. I've never played a trumpet and I don't know the fingerings, but I know you blow into one end and press the three buttons. I know you do something with your lips to adjust pitch. Knowing that, I could figure it out on my own with enough time. That doesn't mean you'll be good with just practice. That can vary by person. But you can certainly figure it out. On the other hand, can you just figure out how to make a gyrocopter? Or how about just a generator? If you have no knowledge of electronics or mechanics, it is extremely unlikely that you'd manage to build either without instruction from someone or by reading. No amount of practice will make you able to build those if you don't already have the knowledge.
