I’ve long been a proponent of using analogies while discussing concepts that are highly abstract or technical. They allow one to understand what an expert is saying without necessarily having to learn all the background information required to truly understand.
Another use for analogies is when one is teaching. In this situation, the person the teacher is talking to knows most of the background information that is necessary to understand this new concept. However, the trouble is that the jump, from where they are in their understanding to where the teacher is, is too great, meaning a technical explanation can only get one so far. This is where an analogy can help.
(Advanced apologies for using an analogy for an analogy.)
Analogies are like training wheels. Their purpose is to give the person the ability to make that conceptual leap to the new idea, much like training wheels allow a person to get used to riding a bicycle before riding on only two wheels. Furthermore, analogies shouldn’t be thought of as a replacement to complete understanding of a concept. Instead, they can help situate one in an idea before it becomes familiar enough that the analogy is no longer needed.
That last distinction is incredibly important, because I hear experts all the time say things like “this analogy is okay, but it isn’t quite right.” Of course it’s not exact. If it were, the analogy would be the concept itself! Instead, the purpose of the analogy is to introduce a concept to someone in a way that does not seem totally foreign. Once the concept is well understood, then by all means drop the analogy if it isn’t perfect.
Think of an analogy as a useful step towards the understanding the complete picture, and not as a perfect equivalent to the concept at hand. Most times, the latter path does not exist. By taking the former approach, you’ll be able to better take advantage of the power of analogies.