What is deductive logic?

Answer 1

Logical arguments are usually classified as either 'deductive' or 'inductive'.

Deduction: In the process of deduction, you begin with some statements, called 'premises', that are assumed to be true, you then determine what else would have to be true if the premises are true. For example, you can begin by assuming that God exists, and is good, and then determine what would logically follow from such an assumption. You can begin by assuming that if you think, then you must exist, and work from there. In mathematics you can begin with some axioms and then determine what you can prove to be true given those axioms. With deduction you can provide absolute proof of your conclusions, given that your premises are correct. The premises themselves, however, remain unproven and unprovable, they must be accepted on face value, or by faith, or for the purpose of exploration.

The best way to learn is by doing. Solve the following problem using deductive logic:
http://www.public.asu.edu/~royal/Firing_Squad.htm

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Answer 2

Logic is a systematic way of reaching conclusions through unbreakable links.

Deductive logic is logic that starts with a general point - and moves toward a specific conclusion.

This is opposed to inductive logic, that starts with a specific point and moves toward a general conclusion.

An example of deductive logic;

A mammal is a living thing, that has lungs, that drinks milk, that has hair or fur - therefore "Spot," is a mammal.

Inductive logic;

Spot has fur, drinks milk, has lungs and is, therefore, a living mammal.

But always remember - just because something is logical, doesn't mean it is right! (Sorry, but this is true:^)

Answer 3

Deductive logic is a methodical way of thinking to reach a desired conclusion. Think of Sherlock Holmes- he had to do some fancy detective work, and use deductive logic to solve several crimes.
Or, I guess McGuyver would do as well. :)

Answer 4

to deduce is to make a conclusion based on clues- for example: the animal is small, has feathers, a beak, and makes peeping noises. i deduce it is a bird. deductive logic is using this type of reasoning to come to conclusions. if the "clues" are true (ie it is true it is small, it is true it has feathers, and it is true it has a beak), then the conclusion has to be true (i.e. it must be true it is a bird).

Answer 5

its a way of subtracting possibilities to determine something...

lets say i go home, and there is writing (in english) in crayon on my wall. the only living things home all day were my bird, my dog, my son, and his cousin from argentina, Pedro...

now, the bird was in the cage, the dog doesnt have thumbs to hold a crayon, pedro doesnt know english.... so, it must have been my son!

i just took away options logically until there was only one thing left.

Answer 6

deductive

Answer 7

check this out

http://education.yahoo.com/reference/