The limitation of our knowledge of a thing does not affect the existence of that thing.
"I have swept space with my telescope and found no God," said the great Lalande; but God was, and is, and evermore shall be, despite the mighty astronomer's faithless conclusion.
That it is not at present believed to any practical extent that in those cases demanding the services of a skilful surgeon a metaphysician would be equally or more competent to carry them safely through, does not hinder the possibility that in such cases, even at the present stage of advancement in the science of mental healing, a practicing scientist would be all-sufficient for the emergency.