How is an argument from ignorance defined?

An argument from ignorance is defined as one that asserts a proposition is true simply because it has not been proven false, or vice versa. This reasoning relies on the absence of evidence against a claim as a means of validating that claim. For instance, if someone argues that a certain phenomenon must exist because no one has definitively proven it does not exist, they are employing an argument from ignorance.

This type of reasoning is problematic because it places the burden of proof on those who would disprove the claim, rather than on the person making the assertion. It creates a logical fallacy by suggesting that the lack of evidence against an idea is sufficient to accept it as true. In contrast, other options either describe different logical processes or do not fit the definition of an argument from ignorance.