Circularity
Posted in Critical thinking, FlawsA circular argument uses a conclusion as one of its reasons so the argument goes around in circles getting nowhere. For example:
Your hair is brown because you have brown hair
The problem with this argument is that if you believe the reason then you must already believe the conclusion rendering the argument pointless. On the other hand if you don't believe the conclusion then you cannot believe the reasons given to support it. Either way the end result is you believing what you started with.
Begging the question is a special type of circular argument where the reasons can only work if the conclusion is assumed to be true. For example:
You can trust me, I wouldn't lie to you
To believe the reason, "I wouldn't lie to you" you must accept the conclusion, "You can trust me".