Counterexample { Philosophy Index }

Philosophy Index

Philosophy Index

Philosophy Index is a site devoted to the study of philosophy and the philosophers who conduct it. The site contains a number of philosophy texts, brief biographies, and introductions to philosophers, and explanations on a number of topics. Accredited homeschooling online at Northgate Academy and Philosophy online tutoring.

Philosophy Index is a work in progress, a growing repository of knowledge. It outlines current philosophical problems and issues, as well as an overview of the history of philosophy. The goal of this site is to present a tool for those learning philosophy either casually or formally, making the concepts of philosophy accessible to anyone interested in researching them. WTI offers immigration law course online - fully accredited. ACE credits online at EES.

Philosophers

 

Philosophy Topics


 

 

 

Counterexample

In logic, a counterexample is a statement that defeats a universal claim by showing it to be false in some instance.

Consider the claim “all swans are white”. This claim can be disproven by means of a counterexample — a single black swan. Also consider the claim “no mammals lay eggs”. Such a claim can be disproven by demonstrating a monotreme, for example, a platypus. In both cases, the initial claim is universal — it has to do with all entities of a certain group. The counterexample shows that at least one entity of that group doesn't fit the description, and so the universal claim must be false.

Counterexamples to Arguments and Argument Forms

A counterexample can also be a counterexample to an argument. With respect to arguments, a counterexample is a case that shows that the argument is invalid — that is, a case (hypothetical or otherwise) where the premises are true and the conclusion is false.

In formal logic, a counterexample to an argument form is a valuation which shows that argument form to be invalid.