In the Advancement of Learning, Bacon writes:

"Another diversity of method there is [he is speaking of the different methods of communicating and transmitting knowledge] which hath some affinity with the former, used in some cases by the discretion of the ancients, but disgraced since by the impostures of many vain persons, who have made it as a false light for their counterfeit merchandises; and that is enigmatical and disclosed. The pretence whereof [that is, of the enigmatical method] is to remove the vulgar capacities from being admitted to the secrets of knowledge, and to reserve them to selected auditors, or wits of such sharpness as can pierce the veil."

From Bacon, Shakespeare and the Rosicrucians. W.F.C. Wigston