CathInfo.com

I am assuming though that you have no positive doubt concerning your own baptism.

A positive doubt is one that is based on some verifiable, specific fact or problem.  Example:  You watch a baptism being performed and priest says all the correct words/form, but you notice that he pours the water on the baby's neck, instead of the forehead.  You ask the priest later about it (and the godparents agree with what you saw) and he says "it's fine, no problem".  But you later research and find that this MIGHT be invalid.  The point is, your doubt is based on two facts....
1) you witnessed the pouring of the water done in a non-normal way, 
2) the priest and godparents agreed it was non-normal, but said it wasn't a problem.  

This is a positive doubt because it's based on evidence, with eyewitnesses.  In other words, this doubt is not just your imagination; something "odd" did happen.


A negative doubt is just an anxiety, a worry, or a wondering.  It is not based on anything, except your own imagination or fear.  You cannot point to anything which is non-normal or odd.

You may know this, but I wanted to clarify.