Thursday, March 21, 2019

Sherlock Holmes: Master of Deduction? or Abduction?

In Conan-Doyle's stories, Sherlock Holmes, the world's greatest detective, was a "master of deductive reasoning".

But, actually, he was an expert at abductive reasoning, because Holmes combined observations with known facts.

The 3 forms of logic reasoning:

1. Deductive:  Using facts to go from the general to the specific.  Example: Oceans have salt water, the Pacific has salt water.  Therefore, the Pacific is an ocean.

2. Inductive: Using facts to go from the specific to the general. Example: The Pacific is an ocean.  The Pacific has salt water.  Therefore, all oceans have salt water.

3. Abductive: Combining an observation with a known fact, to draw a probable conclusion. Example: I see that this body of water is salty.  Oceans have salt.  Therefore, this body of water is an ocean.

The difference between Deduction and Abduction is that the former involves only using known facts, while the latter involves both observations and facts.