You and I have talked past each other on this point to a degree, but there is also a completely different stance on what counts as 'having been learned' in terms of diving.
It simply does not matter (to me) if someone can repeat any scientific knowledge of any kind about diving. It's in the course, and we test for that, but that is basically bookkeeping. In fact, it only matters if, in practice, the rule of behavior involved is followed in practice. The only place where learning about gas expansion matters is in the water, because that is the only point at which there are consequences to the facts.
You may say it is learned somewhere else.
I will still insist that saying someone has 'learned' it simply is immaterial outside the water, since many people who have 'learned' this, still hold their breath the first time they take the regulator out of their mouth, some still fail to watch their ascent rates. You say they have learned it on land. I say (and say always) land experience and knowledge, and lecture and briefings, etc. don't count for anything except to the degree to which they result in correct water behavior. You miss my main point: Lecture and briefings may well help some students. But there are a lot of instructors who pour focus into lectures and briefs who long ago simply stopped focusing on the details in the water, which is the only point at which being an instructor matters at all.
There are all manner of critical things that are leaned in lecture and other talking situations. To name a few: decompression theory and calculations, ""reading" a beach by watching the break, gas management, alternate breathing gas uses and calculations, dangerous marine animals and treatment for such injuries, equipment repair and troubleshooting, etc., etc., etc.
If the above were not true not we could all get cave certified by reading good books, because that would mean that learning outside of the water counts for something. You say it does, I say it doesn't. It is an necessary evil, but nothing 'learned' above water counts until it is demonstrably put into practice in the water.
I say that there are some few naturals who have the skills and background to read a book and preform well above the level of "full cave." Could "all" do that, no, but the same is true, only more so, for entry level, there are a fair number who could be handed a book in the morning and dive quite competently in the afternoon ... but there are also those who will never learn, no matter the quality of instruction and duration of training, because they are just not suited to it, e.g., they lack the prerequisites.
This goes similarly (with a different emphasis) in the discussions about the complicated exercises of a rescue class. If exercises are being repeated with mistakes when they are put into practice, how can they be said to have been learned before the point at which they are done (repeatably) without mistakes? Doing something once without mistakes might just be an accident. Doing it every time without mistakes is the only point at which something can be counted as having been learned, because the correct behavior is actually being (repeatably) demonstrated. Diving is a physical activity. And a statement about having learned something can only be justifiably asserted when it is repeatably shown to be part of an established behavior. Previous to that point it might just be accidental coincidence of circumstances. An instructor who lets one repitition count as proof something having been learned is missing that fact.
You are falling into the scholastic trap of assuming that there is a mind/body dichotomy. Let me tell you about an experimeent, that unfortunately I have lost the reference for: two groups of children who had never played basketball where taught to shoot layups. Then one group was given a hour a day to practice, with coaching, shooting layups. The second group was placed in comfy chairs in a darkened room while a coach talked them through the mechanics of shooting a layup with perfect form. The second group was encouraged to image themselves shooting layups with perfect form. After two week the two groups were tested and scored both on form and on the percentage of scoring layups that they shot. Guess what? The "imagers" did better, both in form and in the number of made baskets. So don't be so sure that you've got the, "one best answer." When I have had especially difficult and intricate tasks that had to be done quickly, at depths that induced significant narcosis, I'd first do the task in a pool or shallow water and then I'd visualize doing the task, over and over and over again. In fact, just before I'd enter the water, I'd visualize it one last time. Often, even with the stress of the dive, the dark, the depth and the narc, I'd successfully complete the task more rapidly that I ever did in the pool or in shallow water. So ... where did I learn to do the task? Where did the basketball visualizers learn to shoot the layups?
It is simply a fact that most divers admire the instructor of the course they consider the 'hardest' as having been the best instructor, because those divers see the chasm between their own poor performance and the instructors effortless performance. Despite a demonstrated gap in the rescue class organization (being made to do full exercises before the correct patterns were fully ingrained into muscle memory) , you still refers to that instructor as admirable. Why were mistakes made?
Again I wonder about your sample. My goal with students is to reduce the "chasm" between my students' performance and my ability to virtually nothing, and I am often able to do just that. I can't give them the years of experience, they have to do that on their own, but I work very hard to have them starting off standing on my shoulders, not trailing in my wake.
As I said, the fault being made the students, not the instructor's. I am not saying that the instructor was a bad person. I am saying that the example you gave is a pretty good example of 'less than perfect' organization and 'less than perfect' attention to detail on the part of the instructor.
Everyone makes mistakes. My point is that with more attention put on things outside of the water, an instructor who fails to notice that "I was dwelling on some things, and forgot to do other things", is more likely to have spent up his error free performance quota out of the water.
Nothing matters but the students performance in the water, and any instructor, providing they are laserfocsing their attention the student, will notice these problems.
Lots of things besides the students' performance in the water matter, and I submit that until you understand that you will be stalled in your development as an instructor. Teaching is a holistic undertaking and requires that that you get all the bang for the buck that you can out of lectures, recitation sessions, confined water teaching, confined water practice sessions and open water teaching and practice sessions. I recommend that you turn that laser on to your lectures if they are not yielding the results that you think they should be rather than criticize instructors who are able to use that time to excellent effect.
