A Word About Abduction

Abductive reasoning is something that you may not have heard of, but rest assured, of the modes of thought responsible for Sherlock Holmes' brilliance, it is the most important. It combines rigid logical connections of deduction with the fluidity of induction.

Simply put, abductive reasoning is what Holmes uses to do his thing.

Holmes is famous for the line, "Once you have eliminated the impossible, whatever remains, however improbable must be the truth." Strictly speaking, this is true. When one has a set of n possible options, eliminating (n-1) of these options will result in one option remaining. What this phrase fails to take into account is how one actually generates this list of n possible options.

The fact is, you CAN'T just make up a list of all of the possible options. Any list of possibilities you can come up with will be incomplete. You can always add things like, "OR, aliens could have abducted him, probed him, then staged his murder to make it LOOK like he was poisoned." There's NO WAY that's what happened, but speaking deductively, you also can't 100% rule it out. That's where abductive reasoning comes in.

It allows you to gauge possibility in a slightly less rigid way, while still keeping most of the logical progressions we love about deduction. This mode of thought is what allows Sherlock Holmes to generate his list of possible explanations for how the crime may have occurred, after which point he can apply his rigorous logic and his brilliant detective skills to narrow the possibilities down to a single solitary solution.

How does one apply this reasoning to one's own {cases, life, questions} you ask? Two things above all else benefit a detective in this endeavor - a formidable memory and an abundance of imagination.

Sherlock Holmes manages to generate possible scenarios so quickly partly due to his vast knowledge of crimes already committed. As he is so fond of saying, "There is nothing new under the sun." Thus, he is able to extrapolate possible means, motives, and even weapons - from crimes of a similar nature which have already happened. When he is not able to find a suitable comparison, his mind searches for new and unexpected ways in which events could have transpired. An excellent way to inspire such strokes of investigatory brilliance is to ask one's self, "What if it didn't happen that way?" or "How could this have been possible given X and Y?" or even "If I were the killer...?"

Long story short, the abductive way to find the answer is to create a set of possible options, one of which HAS to be the answer, and keep eliminating things until one reaches a solution. It's certainly not glamorous, but damn if it isn't Holmes.