Question

Sherlock Holmes was a fictional detective created by the British author Sir Arthur Conan Doyle. Holmes was renowned for his reasoning talents, in particular his ability to "deduce" the causes and perpetrators of spectacularly heinous crimes. For this Discussion Board Forum, I'd like you to view this video (see above -- ignore the Greek subtitles) and then read "The Adventure of the Speckled Band." (It's available in LM2: Sherlock Holmes -- The Speckled Band.pdf.)

Many of you reasoned very well on this Forum. You saw that Holmes, for all his talk about deduction, was really reasoning inductively most of the time. His conclusions are at best probable, and not certain, in the case of the hat. In the short story (“The Speckled Band”), it is possible to reconstruct some of Holmes' arguments as deductive, but they too (as Holmes presents them) are best construed as inductions – inferences that are based on experience in which the conclusions, even if the premises are true, can nonetheless be false.

What is interesting is that, when reconstructing Holmes’s logic, we can make it either inductive or deductive by merely changing the form of the argument. Let me give you a very simple example:

In the “Hat Trick,” Holmes concludes that the owner of the hat, Henry Baker, must be highly intellectual, because the hat size is large, and anyone with a large head must possess a substantial intellect. As you may have noted, there is a missing premise here – namely, that cranial volume correlates positively to intellectual prowess, or something to that effect.

This line of reasoning can be presented either deductively or inductively. Furthermore, if it is presented deductively, it can be presented either in categorical logic or in propositional logic. (Categorical logic was invented by Aristotle nearly 2500 years ago; propositional logic was invented in the 19th century and came to prominence in the 20th century in Russell and Whitehead's Principia Mathematica. We will study propositional logic in the last part of this course. Stay tuned!)

YOUR THOUGHTS ON THIS PIECE.

Answer 1

My Opinion

This piece of writing mainly speaks about the difference between 2 types of scientific reasoning such as Inductive reasoning and Deductive reasoning. Sherlock holme's logic is mostly inductive but it is possible that we can construct the logic in both deductive and inductive manner. Deductive reasoning is valid reasoning which begins with a general hypothesis, then speaks about a premise which is specific and finally reaches a valid logic conclusion. Inductive reasoning, on the other hand, is exactly the opposite of deductive where one creates broad generalization from data which are specific and reaches to a conclusion which is not actually logical. Personally, I feel deductive reasoning is the one which I personally prefer as compared to inductive reasoning as reasoning is more valid and logical when deductive than when inductive. I have felt that most of the reasonings I make on my personal life are more of deductive than inductive.