Abstract
The argument from ignorance is an informal fallacy that holds either that a statement not known to be true or proven true is false, or a statement not known to be false or proven false is true. For example, some creationists hold that since the theory of evolution has not been proven to be true, it is false. There is, however, a subtlety to this fallacy that is exploited in Richard H. Gaskins's far-ranging study of rhetoric and persuasion in modern legal, philosophical, and scientific communities. The argument can assert that no evidence to support a claim entails that the claim is false if all the relevant supporting or refuting evidence has been collected. Thus, if a creationist claims that the earth was created some five thousand years ago, a critic could reply that abundant evidence refutes the claim. This additional claim in the argument, however, involves controversies about appropriate and adequate evidence, as well as questions of what Gaskins calls "finality and legitimacy." How long should one proceed with the search for evidence and how should one justify the procedures?