coining a fallacy.

Plantinga’s Fallacy Claiming that if S fails to have evidence for her belief that p, then S either doesn’t know p, or is irrational/unjustified in believing p.

Example:  “What’s your evidence that human persons have intrinsic moral worth?” 
“I have none.” 
“Then you don’t know that they do.”
“You just committed Plantinga’s Fallacy”
“Who the ef is Plantinga?” 

a sound argument for God's existence.

If God does not exist, then you cannot be perfect.
You can be perfect.
Ergo, God does exist.

on being a part of this world.

But, I don't want to push my chips forward and go out and meet something I don't understand. A man would have to put his soul at hazard. He'd have to say, "O.K., I'll be part of this world."