By the great and powerful mathematician, Zorvath P. Fizzypop, PhD.
Let T be a completely arbitrary and non-existent entity. Then, the probability of T being real is 0.
Proof: Because, honestly, we made it up.
If the Blerg isn't real, then it's definitely not real.
Sub-Theorem 1: The Blerg has no actual existence in the physical world.
Sub-Theorem 2: The Blerg's only existence is in this, our most esteemed and utterly fabricated theorem.