By 33rd Degree Freemason, Many P. Hall – The art of healing was originally one of the secret sciences of the priestcraft, and the mystery of its source is obscured by the same veil which hides the genesis of religious belief. All higher forms of knowledge were originally in the possession of the sacerdotal castes.
The temple was the cradle of civilization. The priests, exercising their divine prerogative, made the laws and enforced them; appointed the rulers and controlled them; ministered to the needs of the living, and guided the destinies of the dead.
All branches of learning were monopolized by the priesthood, who admitted into their ranks only those intellectually and morally qualified to perpetuate their arcanum. The following quotation from Plato’s Statesman is apropos of the subject:
In Egypt, the King himself is not allowed to reign, unless he have priestly powers; and if he should be one of another class, and have obtained the throne by violence, he must get enrolled in the priestcraft.”
Candidates aspiring to membership in the religious orders underwent severe tests to prove their worthiness. These ordeals were called initiations. Those who passed them successfully were welcomed as brothers by the priests and were instructed in the secret teachings.
Among the ancients, philosophy, science, and religion were never considered as separate units: each was regarded as an integral part of the whole. Philosophy was scientific and religious; science was philosophic and religious I religion was philosophic and scientific.
Perfect wisdom was considered unattainable save as the result of harmonizing all three of these expressions of mental and moral activity.
Source: Many P. Hall The Secret Teachings of All Ages – Hermetic Pharmacology, Chemistry, and Therapeutics