Is there a term for the "God of the Gaps" fallacy sans God?

Question

As I understand the "God of the Gaps" fallacy, it's summed up as:

We don't have an explanation for this phenomenon. The lack of explanation proves that God did it.

This same logic can be applied in other instances which don't involve God:

We don't know what that moving light in the sky is. It must be an alien spaceship.

or

Some people just seem naturally wiser than others. That, would be explained by them as having had rich experiences in previous lives, so this is a proof of reincarnation

Is there a name for this fallacious way of thinking? It is broader than "God of the Gaps", but still uses an otherwise unsolved question as proof of a contentious assertion.

Answer 1

First off, I would suggest looking at the meta-post about fallacy questions (Sample/ Guide: What is the name of fallacy: A implies B. Therefore C?). There's two things I want to highlight before answering your question from it:

1. The distinction between formal and informal fallacies
2. The limited value of naming fallacies.

If I were to name your fallacy, I would call it an ad hoc hypothesis fallacy -- this is not identical to ad hoc, ergo propter hoc. Instead, it just means that we are making a solution for what we encounter rather than thinking through it.

But again, the point is not to "name the fallacy" the point is to understand what is going on that is invalid. In this case, it is presumably without justification that we are supplying an outlandish explanation. This is clearly informal because words like "outlandish" don't immediately give themselves to rigorous definition. Instead, they depend on background knowledge for us to decide what sorts of things are outlandish or not (is being able to move from one side of the globe to another in a day outlandish? Answer in 1800: Yes. Answer in 2015: No).