Lets look at some simple logic to prove that anyone who disagrees with you in certain manner is nonexistent.
First we accept as truth/fact, the common phrase, "I think, therefore I am."
Start:
If my_thought = true then my_existence = true
Next, we get wait for someone to disagree with us, in particular, they must say "I think not."
If their_disagreement = true and phrase_you_used$ = "I think not." then goto Disprove_existence
Last, we say to them, "Therefore, you are not."
Disprove_existence:
if your_thought = false then your_existence = false
print "Therefore, you are not."
goto Start
end