I agree that more education comes from practice than from books. It's why I subscribe to the "dive more, take less classes (initially)" attitude. I believe there is absolutely a time and place for formal education, as well as informal education with mentors. I tend to prefer latter and supplement it with a healthy dose of reading anything and everything I can on a particular subject.
Several years back, I would have totally agreed with your statement. However over the years, the certification standard has dropped considerably. This isn't necessarily wrong in-itself, but today's diver must understand that many diver training programs are designed to provide the student with a minimum level of knowledge and skill; suited to dive with a DM in clear warm water without natural hazard. Years ago the training was more robust.
The art of any field of study is never learned from books... no matter how many books you read. That has to be gained by experimenting on your own.
Again I agree, but I don't believe it is wise to "experiment" until the diver has a solid foundation of skills and knowledge. As we discussed, this may best be done through further instruction with an Instructor/Mentor (Instructor certification is an option).
But the basis of any education, be it algebra, diving, or other can be learned from a book (and forums like this one, these days) well enough to get you started on a reasonable path of safe execution of that field of study. Especially now, when things like the 5 rules for cave diving have already been developed and are in the public domain.
I think if you wanted to 'get started' in Cave Diving, reading about the "5 rules" will only get you into a lot of trouble. That is not to say that you need to take a Cave Diving Course; I learned from a friend and am now a CD Instructor. Years ago there were more people who did CD uncertified than there were certified. The same can be said for any type of diving. People can learn a skill in a number of different ways. Personally if given a choice, I'd rather learn the easy way than the hard way. When it comes to CD, the easiest way is to enroll in a class. As more and more people have done this over the years, the ratio of deaths to the number of Cave Divers has decreased. It still is however extremely hazardous (even if undertaken properly).
I think Bob and I may be saying the same thing in different ways, though. A book education will never teach you risk assessment. It will just give you the requisite information (I believe) to do a valid risk assessment. Bob seems to disagree that I could find enough information to do a valid risk assessment, but I contend that's because Bob, not knowing me, doesn't have enough information about my risk assessment skills. I trust mine well enough to believe that I could do a dive safely within my risk tolerance, or decide not to do a dive before seeking formal education, strictly based upon information I can find without ever having done that dive.
I don't think that "knowing you" has anything to do with it. The person doing the assessment cannot hope to undertake it without knowing the environment. Accurate risk assessment is impossible unless the assessing party is aware of the possible hazards. This information can't be found in a book. An example: While mapping a tidal blue hole in South Bight on Andros Island in 1971, the ebb started 15 minutes before I expected (causing increasing current downward into the blue hole). The result was that I almost ran out of air and there was a real risk that I would have been overcome by the current and never get back to the boat. A hazard obviously existed (tunnel structure can vary current intensity). Although I had made 15 or 20 dives in different parts of the Cave system, I didn't properly assess the hazard. I learned through this experience and applied what I learned to future dive plans. Sometimes a book is only a bathroom accessory with a duel function.