Thank you for the information ezzelino. I was wondering if the Discovery rules had been cut entirely from 5th Edition. The details may be enough incentive to acquire "Houses of Hermes: True Lineages". Though it will still be hard to face the "reenvisioning" of House Tremere (of which, to be fair, there have been at least two other versions).
Regarding the study of Magic Theory, there are some points I'd like to make. The first is that I was considering, among other things, how far an independent Magus could advance. Whereas it may be possible for an independent Magus with access to a decent Vis source to study and study and study until he reaches a sufficient level to write a Summa which he can then trade for another, including the "mundane" Arcane Knowledge of Magic Theory, the amount of time and effort required to copy Tractati combined with the limited study for each would make them much lower on the list. In some Tribunals, independent Magi are fairly common. How far the "lone researcher" can progress is an issue which affects the shape of the Order.
The second is that under the new rules, spell researchers and those who do extensive labwork like House Verditius find their progress in Magic Theory inhibited. Under the system which existed previously, a Verditius Maga who spent, say, forty years on labwork and design would accumulate enough XP to bring her Magic Theory well up toward about 18. What this means is that the practical applications of Magic Theory used to yield a genuine return. Now, it doesn't. Those same decades of research combined with basic grounding from her Apprenticeship would give her a Magic Theory of merely 11. Thus, using Magic Theory doesn't really allow one to develop Magic Theory.
Extending the early analogy with mathematical physics, experiments are curcial toward confirming theories and toward gathering the information to forge new and better theories. Those who exist purely in a theoretical framework can often veer wildly from practical ontology. Or, to paraphrase Isaac Asimov, any interpretation of reality is correct if you pick the right postulates. Without experimentation to provide the feedback, theory drifts farther and farther into the purely abstract and untested, allowing errors to creep in. The practical application of Magic Theory should weigh much more heaviy in its development.
Of course, under the 4th Ed. rules, relying on a high-quality copy of Bonisagus' original Authority on Magic Theory was a good way to learn it, too. Magi would examine and reexamine his genius for more on the secrets of Magic. It's interesting that under the analogy we've been using, Tractati can be thought of as major scientific/thaumaturgical "papers" on different aspects of Magic Theory.
The effect that this would have on the game setting is profound. House Bonisagus should be THE most powerful in the Order. Why? Because its sheer proliferation of specialists and researchers combined with the seldom-observed provision of their Oath requiring them to SHARE their knowledge would result in a massive collection and proliferation of these "papers". The number of Tractati discourses at Durenmar would run into the thousands. The writing of Tractati and Summae would be deemed an indispensible and, indeed, required part of Bonisagi life. Jerbiton, with its own emphasis on scholarship, would be nearly as prolific and effective, only diverted by its mundane studies.
The idea of having multiple "mundane" scholars studying Magic Theory makes a limited amount of sense. It's a difficult and abstract concept. One would think that it should require a connection to some type of Supernatural Ability in most cases. Truly exceptional minds could, of course, still grasp it and even excel. The difficulty caused by questions regarding Magic Theory actually served to inspire my first 5th Ed. Companion, a dedicated scholar and Alchemist determined to take the fields as far as possible.
I have more ideas to bring up, but thank you for the input.
We're missing some nice flame-war around here.