Note 159 — BOOK I[1] THE PHILOSOPHERS
Francis Legge translation
τὰ μυστικὰ. The expression generally used for Mysteries such as those of Eleusis. Either he employs it here to include the tricks of the magicians described in Book IV, or he did not mean to describe these last when the sentence was written, but to go instead straight from the astrologers to the heresies. The last alternative seems the more probable.