Kings trembled, Popes winced, the messenger was imprisoned and then escaped walking through the walls or simply vanished, reappearing in another place. The adventurous went into deep caves to consult with the oracles, the medium brought the spirit to speak through trance or materialization. The soothsayer calmed the frayed nerves of the enlightened despot as the enemy approached.
Not everyone is eager to contact the spirit as the spirit has a way of being accurate in their message and information. In many cases communication is with a higher intelligence than our own. When you are face to face with a spirit it is a whole different experience.
The argument about this subject will always rage on. If we really want to find out we might be an adventurous person and seek out the wise oracle. Our naturally curious nature wants to know; is it possible the spirit has a message for me.
Word of mouth and referral is a better way to search rather than to go looking for an Oracle in a cave. When a friend tells you about their experience you are more inclined to listen, and then try it out for yourself. The unseen world of spirit and how it operates is unique to each medium.