Quote Originally Posted by Pureghetto View Post
If there was a person who was just like us in every way except that the person was braindead, had no sensory abilities, and by some magical feat of suspension of disbelief was either not in our physical realm or was not able to interact with it (or invent whatever mentally feasible justification for what I'm trying to say), would that person exist?
A person with no physical presence has no brain or body. A person with no brain or body can't be braindead. Contradiction.

If you assume a contradiction, anything logically follows from it. So yes, he exists, in Fairy Land, and he plays with the Fairies.

When talking about such things as human beings, "exist" implies and requires physical presence.

[qq]One can then make a loose idea that God exists because there are billions of people who have the 'idea' of God.[/qq]

You can't conflate ideas and matter. They aren't the same thing. The idea of god absolutely does exist. (Assuming you can define "god".) A god who is not physically present doesn't exist no matter whether the idea does.

This is the distinction between imaginary friends and real people.