'Proof' by analogy

How often do people use analogies in arguments and debates?  Analogies can be used as a powerful tool for teaching but they are unhelpful as a tool to prove anything.

When I am trying to explain something technical, to visitors at work I use analogies.  Usually I find that these analogies give the visitors the comforting feeling that they understand a little bit of a very technical topic.  They go away and tell people how exciting the science is and I'm sure that they evangelise on behalf of scientific progress in their communities.

If I did not use analogies to explain things, but actually used the detailed theory of the application of  engineering and physics, there would be negative consequences.  For one thing, I wouldn't be able to do it.  I feel that I have a pretty good understanding of the techniques that we use, but only at a superficial level.  I understand a few pockets of the technology with a greater knowledge, (even if not at world expert level).  But when it comes to a detailed expertise on most of the systems I would rapidly get lost.  I simply don't know enough to be able to explain things in technical detail.

This makes it look like a win-win situation to use analogy.  I almost never get a question that I can't answer by analogy, and even experts from other world leading facilities in the same field are usually so impressed with the sheer quantity of impressive equipment that they do not ask anything challenging.  There is an explanation for this of course.  These visiting experts know their own fields well enough that they recognise what they see, and other areas of the technology they tend to ask the same sort of questions as anyone else.

Analogies work in this context, as a teaching aid.

But . . . as a method of choosing how to do something, analogies are often dangerous.  I suspect this explains the hostility that some of my colleagues have to the use of analogy.  This is typical in high technology.  The true experts are often not the best communicators, and they fail to understand how the separate skill of communicating their work to the public is best done.


Religious apologists use analogy too, and I wonder whether they realise that it is dangerous for them to base their lives on such a flimsy line of reasoning.