If you've spent any time in the flight training industry, you've probably heard the phrase "dumbing it down" or some variant. It refers to the act of simplifying concepts for students. Simplifying things if fine, but I cringe every time I hear the advice to "dumb it down". I think most professional flight instructors would agree that aviation, and in particular flight training, has already been "dumbed down" quite enough.
The problem is that there comes a point where things get over-simplified. Over-simplification inevitably leads to misunderstanding and faulty conclusions. I've written previously about some of these misunderstandings (for example, Maneuvering Speed and Turbulence Penetration.) Over-simplification is especially problematic when we're training people who will eventually hold leadership positions in the industry. This includes all commercial pilots—most of whom will spend at least some time as Captain of a multi-crew aircraft, Training Captain, or Flight Instructor.
The caution against over-simplifying comes from Albert Einstein. He is credited with saying,
"Make everything as simple as possible, but not simpler." (http://www.quotedb.com/quotes/1360)
This is sometimes referred to as 'Einstein's Razor', which serves as a counterbalance to Occam's Razor. Ironically, it's more likely that Einstein actually said,
"It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience." (http://en.wikiquote.org/wiki/Albert_Einstein)
But luckily for us, the quote has been dumbed down over the years!
Should we simplify concepts for students? Absolutely. Simplification aids the learning process. But simplifying to the point if inaccuracy is counterproductive. In the language of the principles of learning, it violates the law of Primacy (Teach it Right the First Time!), and will often result in future Supplantive Learning (the need to unlearn the wrong information before learning the right information).
Should we use analogies that are 'imperfect'? Absolutely. Analogies are a form of simplification that aids the learning process by relating a new concept to an old and familiar concept. As such, analogies are very effective training aids. But they are almost always limited, and will promote misunderstanding if carried too far. As such, it's important that when we use analogies, we also highlight the limitations of the analogies and use them to eventualy build a more standalone understanding of the new material.
The bottom line here, of course, is that when you are teaching (in aviation or anywhere else!), you should make everything as simple as possible, but not simpler.