Tuesday, February 4, 2014

Formalities (Part 2)

Doing alright so far? Good. We've got a long ways to go.

Some more food for thought:
-What is induction?
-How is it different from deduction?
-Which is better?
-How does Holmes REALLY get his answers?

Induction:
Essentially, induction is a form of logic not as bound by 100% truth and falsity, but rather makes use of what's called the Balance of Probability in order to determine a probable answer. For a side-by-side comparison, we'll head back to the white-house example from the last post:

Let's say I've done a fair amount of walking about my neighborhood. Let's also say that I, being a very observant fellow, notice something strange - every single house that I pass is white. Mind you, I haven't seen every house in the neighborhood, but I have seen quite a few.

Is it logical to suggest that any given house in the neighborhood is white based on the above data?

Through deduction, absolutely not. We have no True/False statements to deal with, and we can't stretch the existing data to encompass the whole neighborhood. The fact is, there are still some houses we know nothing about, so we cannot "deduce" anything about the color of a random house.

Through induction... maybe. Inductive reasoning is built around the idea that if one's premises are true and/or acceptable, then the conclusion is likely to be true or acceptable. Not nearly as powerful as deduction, but much more far-reaching.

If it doesn't sound impressive, it's because it's actually not. Inductive reasoning is something that most people do without thinking about it, and therefore don't put any real thought into how logical/illogical their intuitions are. To give you a better idea of what I mean, try reading the question another way:

If so far on my walk, I have only seen white houses, what then, should I expect the color of the next house to be?

Which is Better?
Short answer - neither. Holmes answer - they are both invaluable to good detective work. The secret to Sherlock's success as a consulting detective lies in using the different techniques effectively.

To maximize the effect of deductive reasoning, one must break down a situation into simple propositions (facts), and find as many logical connections between them as possible. Don't just guess as to what has happened - find out what MUST have happened. This takes a lot of work, and you will almost always be able to find alternate explanations for the facts you have at your disposal - the trick is using what you've got to narrow down what logically could NOT have occurred, and what you are left with, as Holmes famously puts it, will be the truth.

In order to get the most out of induction, you'll want to be asking lots of questions. In fact, simply asking why something happened the way it did is sometimes enough to unravel even the strangest of situations. You'll want to bear in mind that induction is only going to point you in the direction of a solution, not hand it to you. To work with this restriction, you'll want to be as aware as possible of the likelihood of every action taking place in your investigation. With very few exceptions, the more support you can find for a particular theory, the higher the Balance of Probability  on that option. Don't forget - the beauty of induction is that you aren't forced to make a choice. If a few theories are competing for your attention, try them all. Then go back and think it over. The truth will typically make itself known upon sufficient examination.

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