Final answer:
The fallacy that occurs when an issue or argument is supported due to a lack of contradictory evidence is called the appeal to ignorance.
Step-by-step explanation:
The fallacy that occurs when an issue or argument is supported due to a lack of contradictory evidence is called the appeal to ignorance. It is a type of fallacy of weak induction, which relies on evidence that is too weak to firmly establish a conclusion. In the case of the appeal to ignorance, the lack of evidence is used as justification for drawing a definite conclusion.