Appeal to ignorance is a fallacy that claims something is true because it has not been proven false. Or false because it has not been proven true. The absence of evidence is treated as evidence. It is not. You cannot prove a negative. The fact that no one has proven there is no ghost does not mean ghosts exist. It means no one has proven either way.

The fallacy is common in debates about God, aliens, and conspiracy theories. You cannot prove God does not exist, so God exists. That is the fallacy. The correct position is agnosticism: we do not know. The burden of proof lies with the person making the claim. The claimant must provide evidence. The skeptic does not have to prove the negative.

Appeal to ignorance examples

• No one has proven aliens do not visit Earth, so they do.
• You cannot prove God does not exist, so God exists.
• No one has shown the vaccine is unsafe, so it is safe.
• Scientists have not explained everything, so the theory is wrong.
• There is no evidence of fraud, so the election was fair.

Appeal to ignorance is sometimes called argumentum ad ignorantiam. It is a fallacy of irrelevance. The lack of evidence is not evidence of anything. It is just lack of evidence. In science, the absence of evidence is often the starting point for investigation. It is not a conclusion. In law, the presumption of innocence is not an appeal to ignorance. It is a procedural rule. The prosecution must prove guilt. The defense does not have to prove innocence. That is different. The appeal to ignorance is a logical error. It confuses what we do not know with what is true. The world is full of things we do not know. That does not make them true or false. It makes them unknown.