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What Is the Difference Between Inductive and Deductive Reasoning?

In trying to work through a problem, someone may use both inductive and deductive reasoning.
Isaac Newton famously used inductive reasoning for his theory of gravity.
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  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 23 July 2014
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Inductive and deductive reasoning are both approaches that can be used to evaluate inferences. Deductive reasoning involves starting out with a theory or general statement, then moving towards a specific conclusion. Inductive reasoning, on the other hand, takes a series of specific observations and tries to expand them into a more general theory. Each approach is very different, and it is important to be aware that both inductive and deductive reasoning can end up with false results, especially if the initial premise of the reasoning is false, in which case the results are said to be “unsound.”

Inductive Reasoning

A simplistic example of inductive reasoning might start with an observation such as “All of the cows I have ever seen are spotted.” One might, in turn, think that therefore all cows must be spotted. This is not actually the case, but given the available information, one might be forgiven for thinking it. The next step in this logic might involve attempting to find things which disprove the assertion that all cows are spotted, as might be done by asking other people if they have seen cows which are not spotted.

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Inductive reasoning is commonly seen in the sciences when people want to make sense of a series of observation. Isaac Newton, for example, famously used inductive reasoning to develop a theory of gravity. Using observations, people can develop a theory to explain those observations, and seek out disproof of that theory. As can be seen in the cow example above, one of the major flaws with inductive reasoning is that it is dependent on observations, and when observations are incomplete, unsound results may be formulated.

In a famous example of inductive reasoning, some people in the ancient world believed that meat spontaneously gave rise to maggots. Their conclusion was based on the observation that if meat was left out, maggots would appear on it. Someone else decided to test this theory by seeking for disproof — would it be possible to leave meat out and not have maggots appear? By sequestering meat in various containers next to fully exposed meat, the scientist realized that the maggots were, in fact, the result of eggs laid by flies.

Deductive Reasoning

With deductive reasoning, one takes a general theory or idea, tests it, and moves through a sequence of ideas to arrive at a specific conclusion. It is possible to arrive at an unsound result by using an initial premise which is false, as in this case: Every animal that eats mice is a cat. Rover eats mice. Therefore, Rover is a cat. The goal of deductive reasoning is to arrive at a valid chain of reasoning, in which each statement holds up to testing, but it is possible for deductive reasoning to be both valid and unsound.

Both Useful Approaches

The brain is so adept at both deductive and inductive reasoning that it often does it on a level which people are not fully aware of. Especially in the case of children, this type of reasoning is used to make sense of the world and the things observed in it. As can be seen, it is possible to use both approaches to explore a logical problem.

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Discuss this Article

anon950648
Post 26

Looked at a few explanations on other sites and not one was as clear and precise as this one.

Thank you.

anon101866
Post 8

Best explanation seen so far!

anon95918
Post 6

excellent effort. Thanks. Tarunes

anon92023
Post 5

Great article! thank you.

anon90478
Post 4

it really helped. Thank you so much!

anon83885
Post 3

This was a helpful article.

anon80271
Post 2

thank you.

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