Induction vs Deduction
In logic theory, Induction and deduction are prominent methods of reasoning. Sometimes people use induction as a substitute for deduction and erroneously make false and inaccurate statements.
Deduction
Deduction method uses more general information to arrive at a specific conclusion. It can be viewed as reasoning wherein the conclusion is considered as the logical following of the premise or argument. The validity of the conclusion is based on the validity of the premise or argument. The conclusion strongly depends on the premises or the arguments in a deduction method.
Following are some examples of deductive logic.
o The solar system has 8 planets
o Earth is a planet in the solar system
o Therefore, Earth is one of the eight planets.
Considering another example
o Party A won the election
o Mr. X was the candidate from party A
o Therefore, Mr X will get the office.
In another picture, it can be viewed as a flow from a larger general set of information to a narrow but specific set of information. The process of deduction can be summarized in the following steps.
Induction
Induction is a process where individual arguments and premises are used to develop a generalization or a conclusion that can be attributed to much more than the initial subjects. In this method, the conclusion may be validated or disproved by the preceding premises.
Following are some examples for inductive reasoning;
o All the rivers I crossed flows toward the ocean. Therefore, all the rivers are flowing toward the ocean.
Above induction is true for all rivers. Consider another induction
o Month of August has experienced drought for the last ten years. Therefore, there will be drought conditions here for every August in future. This induction may hold true or may not.
The induction process can be seen as arriving at a general conclusion for a larger set by considering the results of few very specific cases. Process can be viewed as follows;
Induction vs Deduction
• Deduction is a form of logic that achieves a specific conclusion from the general, drawing necessary conclusions from the premises. (In deduction, bigger picture of the understanding is used to make a conclusion about something which is similar in nature, but smaller.)
• Induction is a form of logic that achieves general result from the specific cases, drawing probable conclusions from the premises. (In induction, a larger view is created using a few specific observations available.)
Very good writing, very clear examples (thanks). But which method is better? Is one more prone to mistakes than the other? Under what conditions should one use inductive v. deductive reasoning?
Both are equally important – you observe and make a theory first (induction), draw conclusions (deduction) and check their validity (again observation) and if not consistent, improve the theory (again induction). Enjoy the loop !!
This is a subject I have tried to clarify in my mind for sometime now. This article gave me the opportunity to get clear I believe. It seems to me that the basic difference between inductive and deductive reasoning is that inductive reasoning leads to a theory or opinion. Deductive reasoning leads to a conclusion which is valid dependent upon the premises being valid. If either premise is not valid or factual, deductive reasoning cannot occur.
Quick note – not all rivers flow to the ocean… some only flow to inland bodies of water.
All rivers do not flow into the ocean. The Jordan river ends in the Dead Sea, not an ocean. False induction.