I will respectfully share my thoughts on a couple of them, noting that I have truly taken much of Andretta's teaching to heart, and have found many of his expressions to be not only truisms but also truths.
1) "There is only one one" (a.k.a. The 'Highlander Principle')
Premise: If your "1" beat (the first beat, the downbeat) is always in the same place, the people who you are conducting will always know where to find it.
- No other beat must be in the same spot that your "1" is.
- Your "1" must always go downwards.
This is fantastic advice in my opinion, and one that all conducting teachers should pass on to their students.
Anyone playing to a conductor whose "2" or "3" is in the same place as the "1" will tell you it can be very disruptive and confusing. It takes me roughly 2 seconds to spot a conductor whose downbeat is always somewhere 'upstairs' or always in a different spot, and it always makes me cringe. (Right now I can almost hear Andretta shouting "THERE IS NO UP!! YOU MUST GO DOWN, DOWN, DOWN!!". )
My own personal observations lead me to believe that a missed entrance or a confused chorus is very often a result of the conductor not properly adhering to the 'Highlander Principle'.
2) "There can be no escape"
Premise: With your "1" locked firmly in place, you are able to completely steer your forces, allowing them no escape.
You cannot allow the orchestra to run away, or yourself to run away with them. If the orchestra don't follow you, you simply stay put until they do.
Now, I think Andretta is on to something, but not completely right. My first teacher at the academy, Frans Rasmussen, took a slightly different approach. His take on control was, that as a conductor you should 'hold the reigns, as if riding a horse'. You don't keep the reigns too tight, or your 'horse' will stall; become too locked to perform freely and will quickly become nervous and at worst obstructive. I like this analogy.
The more rigid 'no escape' policy is powerful under the right circumstances, but I don't believe it to be absolutely true of conducting in general.
Nevertheless, this 'Lex Andrettae' touches on a very interesting phenomemon in conducting: There is a delicate fuse between the conductor and the orchestra that allow a meaningful interaction to take place, wherein the conductor is - pardon the pun - in charge.
Certain actions on the part of the conductor breaks the fuse, and his actual power vanishes. This is a one-way street byt the way; only the Conductor can break it.
A whole variety of actions can result in a broken fuse: correcting something that wasn't actually a mistake, giving wrong cues repeatedly, giving mixed messages about specific playing styles or articulations etc. etc.
Possibly the most devastating one is allowing the orchestra to run away from the tempo you actually want to set. If you don't immedeately interrupt the rehearsal and try to correct this, you will have effectively broken the fuse and lost not only your power, but most likely also the respect of the orchestra. Some orchestras might replace the fuse for you for your next rehearsal together, but some have a strictly one-fuse-policy.
At the moment, we are unfortunately seeing something like this unfold at the Royal Danish Opera's current production of 'Cosi Fan Tutte', where somewhere along the line the fuse was blown, and the orchestra now almost completely ignores their conductor and is trying to play the opera on it their own. The result is of course less than satisfying.
(I cannot say what caused the disruption, as I have not been present at rehearsals.)
3) "It is not our mistake, but it becomes our problem!"Although ideally not a principle of conducting per se, this is another one of my favorite 'Andrettaisms'.
Premise: You must accept, that as a conductor you will have to take the blame for a lot of other people's mistakes, and accept that the ideal quality of your work will always be influenced by mistakes you yourself did not necessarily make.
Of course, this happens a lot, and thankfully it doesn't mean that conductors don't get rightly blamed for mistakes they make, it just means that a lot will appear to be the conductor's fault, when it fact it could be the musician's, the singers', the stage manager's, the director's or someone elses fault. When you take to the podium, you have to be able to carry the weight of that responsability, and never stoop to playing blame games or spending your precious rehearsal time barking at someone for making mistakes. When you are on the podium, their mistake is now your problem, so do what you can to solve it or change your focus.