Asserting a specific belief is true because we don’t know it isn’t true.
Intelligent design, or creationism, is almost entirely based upon this fallacy. The core argument for intelligent design is that there are biological structures that have not been fully explained by evolutionary biologists, therefore a powerful intelligent designer must have created them.
This fallacy is also the basis of every ‘god of the gaps’ claim. When anthropologists find fossil evidence of two descendant species creationists inevitably decry,
Where are the transitional fossils? Without them the only explanation is God.
When a transitional fossil is found, the creations retort “Now there are two gaps. Where are the transitional fossils to fill those gaps? It must have been God.:. This, as you can imagine, could go on forever, until every single generation were to be discovered, which is impossible given how rare it is for fossils to form at all. Asking for more and more evidence is known as moving the goalposts.
Naturally, by using this fallacy, one can insert any baseless claim as the target ‘truth’. If the cause of the big bang cannot be known, it must have been flying space monkeys from the universe-creating spacecraft “Betty Boop”. Pointing out something as unexplained does not further a counter claim.
Science doesn’t know how life began on Earth because it was God.
Doctors can’t explain the coma awakening. It looks like my prayers were answered!
Defenders of extrasensory perception (ESP), for example, often overemphasize how much we don’t know about the human brain. It is therefore possible, they argue, that the brain may be capable of transmitting signals at a distance.
UFO beliefs are founded on this fallacy. Nearly all UFO eyewitness accounts are ultimately arguments from ignorance – lights or objects sighted in the sky are unknown, and therefore it is assumed to be an alien spacecraft.