Sunday, October 16, 2011

Inductive, Deductive

When we first started with inductive and deductive it was a little fuzzy to me so I tried to find ways on how to understand them better and i came across this,

Many people distinguish between two basic kinds of argument: inductive and deductive. Induction is usually described as moving from the specific to the general, while deduction begins with the general and ends with the specific; arguments based on experience or observation are best expressed inductively, while arguments based on laws, rules, or other widely accepted principles are best expressed deductively. Consider the following example:
Adham: I've noticed previously that every time I kick a ball up, it comes back down, so I guess this next time when I kick it up, it will come back down, too. Rizik: That's Newton's Law. Everything that goes up must come down. And so, if you kick the ball up, it must come down.
Adham is using inductive reasoning, arguing from observation, while Rizik is using deductive reasoning, arguing from the law of gravity. Rizik's argument is clearly from the general (the law of gravity) to the specific (this kick); Adham's argument may be less obviously from the specific (each individual instance in which he has observed balls being kicked up and coming back down) to the general (the prediction that a similar event will result in a similar outcome in the future) because he has stated it in terms only of the next similar event--the next time he kicks the ball.

Now i feel much more confident on my judgment to decide which one is which.

3 comments:

  1. That is helpful in determining whether an argument is inductive or deductive. I never really thought of it that way, but it makes a lot of sense. This is a very good example too because there is both inductive and deductive reasoning involved. I appreciate you posting something like this because i was struggling with this also and this does help to clear it up a little. Thanks!

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  2. I'm curious about the source you seem to be quoting.

    Two observations: 1) though popular, the notion that induction proceeds from general to specific, and deduction the opposite, is only sometimes true, and is not really a good general rule (see pp. 36-7 in Hurley). 2) Rizik's version of the argument it not really deductive. Newton WANTED his law to be a priori, but as we now know some things go up and do not come down.

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