Personal Incredulity
Fallacy friday! Argument from personal incredulity.
What is it? It's the argument that someone is making when they say something like "I can't imagine the universe being billions of years old! Therefore it isn't." That's a bad argument and really dumb. It basically asserts that in order for something to be true, or likely to be true, it must be understood properly and be something someone could "understand".
It's a fallacy due to the fact that there might well be a variety of reasons why someone can't "imagine" something. Additionally because limiting possibilities due to our limited understanding of the world and the universe is stupid. Even Atheism is NOT limiting possibilities. We as Atheists aren't saying God (and any other deity) doesn't exist, rather what we are saying is that the evidence presented to us is unconvincing, to us. That is fundamentally different from asserting that God (and once again, any other deity) does not exist.
In order to beat it, you can point out that simply because something cannot be "imagined" doesn't mean it is false by definition.
Arguments from personal incredulity are common. What is your personal experience with this?
Source: http://rationalwiki.org/wiki/Argument_from_incredulity
https://yourlogicalfallacyis.com/personal-incredulity
http://www.trulyfallacious.com/logic/logical-fallacies/relevance/argument-from-personal-incredulity
https://www.youtube.com/watch?v=vXX9koKOkTs (Richard Dawkins!)