- What do I believe?
- Is what I believe sensible and logical or simply a set of ideas which I acquired without a lot of thinking about it?
- Does what I believe explain the world which I observe?
- Are there any inconsistencies in my thought processes? Does belief A logically contradict belief B?
- Are there sensible and logical alternative beliefs that better explain the world which I observe?
From “Common misconceptions about electric circuits”, http://www.physicsclassroom.com/Class/circuits/u9l2e.cfm
But applicable to EVERY BLOODY THING.