I did not say that people could not be self-taught. Intelligent and highly motivated people will usually find a way to do things, as did many of the pioneers of our photographic craft. However, I would wager that a fair percentage of the early daguerreotpe photographers learned their craft from someone else. I don't have the statistics to prove it, but jut based on the fact that knowing how to make daguerreotypes could provide one with a good living makes me suspect that the best folks at the trade were charging others for the learning experience.
Some things are very easy to learn on your own: most of the alternative processes, including palladium and platinum printing, are really remarkably simple. Yet, even here, a person can get a big jump on the experience by taking a workshop with a good instructor. Just seeing how this stuff is done *right* from the get go can save a lot of time in the future. Other processes, say carbon and photogravure, are more complicated and I would venture to say that few people will be able to learn these proceses on their own. Some will, of course, and I am one of them. But I estimate that doing a workshop with a good instructor on carbon or photogravure would save you in the end 6-12 months of work on your own.
The daguerreotype is on another order. Not only is it far more complicated than any of the other alternative printing processes (and I refer to the traditional processes), it is also potentially quite a bit more dangerous. So I really think it makes sense from a number of perspectives to get some training before you start out on this process.
Sandy