The Brick Wall Catechism

The Brick Wall Catechism is a corollary of the Right Direction Catechism. The Right Direction Catechism tells us that when new clues appear, we must be moving in the right direction. Now ask the following: What happens if no new clues appear even though there is plenty of evidence? Answer: we must have made serious mistakes, mistakes serious enough to prevent us from interpreting the evidence properly, the reason why no new clues appear. New clues mean we have done things right. No new clues means we have made major mistakes.

In an investigation, when there are no new clues further gains in the investigation is impossible. When this happens investigators often say they have reached a dead end or hit a brick wall.

The Brick Wall Catechism:

What happens if we hit a Brick Wall?

We must have made serious mistakes.

In simple investigations Brick Walls are relatively easy to deal with: we simply turn back and correct the mistakes that cause them. In complex investigations a Brick Wall could be the occasion for a major crisis. In a complex investigation things can sometimes get murky. Now if we have plenty of evidence and we can make sense of it, new clues should appear. But none has! Could this be our fault? Maybe the new clues are right in front of our eyes except that for some reason we don't see them. True, it is possible that we might have made serious mistakes in the earlier stages but ... where are they?! Mistakes that escaped our attention at the time we made them could escape our attention again when we turn back and look for them.

In a complex investigation a Break Wall could stay with us for a long time, making life miserable. In The Man with the Twisted Lip things were so bad at one point for Sherlock Holmes that he had to ask Watson for help:

“You have a grand gift of silence, Watson .... It makes you quite invaluable as a companion. ‘Pon my word, it is a great thing for me to have someone to talk to, for my own thoughts are not over-pleasant.... It seems absurdly simple, and yet, somehow, I can get nothing to go upon. There’s plenty of thread, no doubt, but I can’t get the end of it into my hand. Now, I’ll state the case clearly and concisely to you, Watson, and maybe you can see a spark where all is dark to me.”