Inductive reasoning. Inductive reasoning (as opposed to deductive reasoning or abductive reasoning) is reasoning in which the premises seek to supply strong evidence for (not absolute proof of) the truth of the conclusion.
While the conclusion of a deductive argument is certain, the truth of the conclusion of an inductive argument is probable, based upon the evidence given.[1] The philosophical definition of inductive reasoning is more nuanced than simple progression from particular/individual instances to broader generalizations. Rather, the premises of an inductive logical argument indicate some degree of support (inductive probability) for the conclusion but do not entail it; that is, they suggest truth but do not ensure it. In this manner, there is the possibility of moving from general statements to individual instances (for example, statistical syllogisms, discussed below). Description[edit] Inductive reasoning is inherently uncertain. An example of an inductive argument: For example: Criticism[edit] Deductive reasoning.
Deductive reasoning links premises with conclusions.
If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily true. Deductive reasoning (top-down logic) contrasts with inductive reasoning (bottom-up logic) in the following way: In deductive reasoning, a conclusion is reached reductively by applying general rules that hold over the entirety of a closed domain of discourse, narrowing the range under consideration until only the conclusion(s) is left.
In inductive reasoning, the conclusion is reached by generalizing or extrapolating from, i.e., there is epistemic uncertainty. Note, however, that the inductive reasoning mentioned here is not the same as induction used in mathematical proofs – mathematical induction is actually a form of deductive reasoning. Simple example[edit] An example of a deductive argument: All men are mortal.Socrates is a man.Therefore, Socrates is mortal.
Law of detachment[edit] P → Q. Deductive and Inductive Arguments A deductive argument is an argument that is intended by the arguer to be (deductively) valid, that is, to provide a guarantee of the truth of the conclusion provided that the argument's premises (assumptions) are true.
This point can be expressed also by saying that, in a deductive argument, the premises are intended to provide such strong support for the conclusion that, if the premises are true, then it would be impossible for the conclusion to be false. An argument in which the premises do succeed in guaranteeing the conclusion is called a (deductively) valid argument. If a valid argument has true premises, then the argument is said to be sound. Here is a valid deductive argument: It's sunny in Singapore. If it's sunny in Singapore, he won't be carrying an umbrella. Here is a mildly strong inductive argument: Every time I've walked by that dog, he hasn't tried to bite me. John is ill. That argument is valid due to its logical structure. If P then Q So, Q All odd numbers are integers. Deduction & Induction.
« PreviousHomeNext » In logic, we often refer to the two broad methods of reasoning as the deductive and inductive approaches.
Deductive reasoning works from the more general to the more specific. Sometimes this is informally called a "top-down" approach. We might begin with thinking up a theory about our topic of interest. We then narrow that down into more specific hypotheses that we can test. Inductive reasoning works the other way, moving from specific observations to broader generalizations and theories. These two methods of reasoning have a very different "feel" to them when you're conducting research. Copyright ©2006, William M.K.