Thread: Deductive Logic: What Is It? Why Do We Do It?

1. Originally Posted by EvidenceOfRedemption
Why do you assume people do use it? A lot of people think they are being logical, but they're merely assuming whatever is left after skipping over important contradictions is true.
Hmm. After reading all these posts I began to doubt whether I knew the difference between deduction and inductions (which never seemed like a problem before)! So what does Webster's Unabridged say? "Deductive reasoning is a logical process in which a conclusion drawn from a set of premises contains no more information than the premises taken collectively." Gives as example "All dogs are animals; this is a dog; therefore this is an animal". This could be false if either of the premises are not true, but if you use this to reach your conclusion you are deducing. "Inductive reasoning is a logical process in which a conclusion is proposed that contains more information than the observations or experience on which it is based." The example given is "Every crow ever seen was black; all crows are black" Here the truth is not final (whether actually true or not) because the premise is not final "All crows ever seen" implies there could be others not seen that are white. So the method is the thing here--whether you accept logical premises, or accept uncertainty.

Coming back to the real world, accepting that everything is uncertain, though some things are more likely than others, certainly sounds and feels more sophisticated, nuanced, etc., but I think we get through daily life using a lot of deductive logic. "The sun does come up in the east every morning. I will set my alarm for X and that will give me daylight time to run."

2. I use deductive logic. I make general observations and come to a specific conclusion

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