(also known as: vacuous argument)

Description: An argument or position is self-sealing if and only if no evidence can be brought against it no matter what.

Logical Form:

Claim X is made.
Reason Y is given for claim X.
Reason Y can not possibly be refuted.

Example #1:

Wherever you go, there you are.

Explanation: You can’t argue against that position, and as a result, it is vacuous, or meaningless. 

Example #2:

Tina: My life is guided by destiny.

Mary: How do you know that?

Tina: Whatever comes my way is what was meant to be.

Explanation: We have the same vacuity problem here, except this one is less obvious and protected by a philosophical belief system.  There is no possible way we can know what "destiny may have in store for us," thus no way to argue against it.  As a result, it is meaningless -- it is the equivalent of saying everything happens because it happens.

Exception: Holding beliefs that are unfalsifiable is not fallacious, especially when stated as beliefs or opinions. This becomes fallacious when an unfalsifiable claim is presented as evidence in argumentation.

Tip: Realize that most superstitious beliefs are centered around self-sealing or vacuous arguments, that is why so many people refuse to let go of superstitious beliefs -- because they cannot be proven false.