Inductive reasoning
From RationalWiki
Inductive reasoning proceeds by starting with results, outcomes, or effects, and then inferring the causes.
[edit] Examples
- Experimental science: obtain data and evaluate competing hypotheses or explanations for how the data came about.
- Medicine: use symptoms presented by patients to diagnose disease.
- Any logical process of the form "If outcome Y, then possible cause(s) X"
Medicine is a good example of how induction differs from deduction. In diagnostic medicine, patients generally do not walk into hospitals and say "I have Disease X. Please tell me what Symptoms Y I should have." If they did, doctors could always reason deductively to find the Symptoms Y for Disease X (Recall that "if X, then Y" is deduction). Instead, patients say "I have Symptoms Y. What Disease X do I have?"
Inductive reasoning has the advantage of being flexible, and has the ability to evaluate competing hypotheses even when information incompatible with the known causes or hypotheses is observed.
The disadvantage of induction is that absolute truth and objectivity are compromised. Outcomes Y could have several different causes X. For instance, a patient may exhibit a sore throat, a runny nose, a rash, and splenomegaly. But there may be several different diseases that cause those symptoms (e.g. Acute Retroviral Syndrome vs. Mononucleosis); the hard task of figuring out which one to diagnose is the reason doctors make big bucks. Furthermore, the diagnosis of one doctor may not be the same as another (although only one of them may be correct); hence, there is a subjective component to induction, and the need for the use of evidence.
