A:

Aristotle:

• No great genius has ever existed without some touch of madness.
• It is the mark of an educated mind to be able to entertain a thought without accepting it.
• All men by nature desire knowledge.
• Those that know, do.
  Those that understand, teach.
• Whereas a rattle is a suitable occupation for infant children,
  Education serves as a rattle for young people when older.
• One soul inhabiting two bodies. (reply when asked "What is a friend?")
• Every art and every investigation, and likewise every
  practical pursuit or undertaking, seems to aim at some
  good hence it has been well said that the Good is That at
  which all things aim.
• Wit is educated insolence.
• Nature does nothing without purpose or uselessly.
• He who is unable to live in society, or who has no need because
  he is sufficient for himself, must be either a beast or a god.