Possible neurological method of proving the existence of magical things

If a person sees a magical thing, for example a unicorn or fairies, then they could be either real or imaginary.
BUT
What if you were to deactivate that part of a persons brain that allowed them to dream and imagine.
If, after having the ability to dream and imagine removed from them, they still saw unicorns, fairies or other magical things then they would have to be real.