“Plato had one Big Idea from which everything else derived. He fundamentally defined reality as that which is permanent and unchanging. Only ideas are permanent and unchanging; anything material deteriorates and decays.”

“In one of Plato's seminars a young man with a rural accent stood up one day and said Plato's philosophy was nonsense. You can have ideas that are neither real nor permanent. They can be mere fleeting fantasies. Plato evicted the student, whose name was Aristotle. Unlike Plato, Aristotle was not one of the gilded youth of Athenian society. His social background was solid middle class. But such was the encyclopedic knowledge he came to exhibit, and his skill in logical argument, that in time Aristotle gained rich benefactors, including the king of Macedonia who hired Aristotle to tutor his young son, later known as Alexander the Great.”

“The central concern of Egyptian art, literature, and architecture was the divine world order -- the pharaoh and the gods, who were essentially one and the same. To the Egyptians, that divine order was eternal and unchanging, but it did not rest on a coherent and defined system of belief. The same god might be seen one time as the sky, another time as a bird; he might have a mythical mother, yet it might be said that he gave birth to himself; the sky could be both a cow and a goddess. The Egyptians did not think in chronological or logical terms but pictured the same phenomenon in a number of different ways.”

“In ethics [Aristotle] had two bright ideas. First, that extreme behavior of selfishness and self-sacrifice don't work for most people; look for the golden mean. Second, good behavior is not a result of either sudden inspiration or harsh control. It is a habitual pattern, which means slow and steady conditioning: 'One swallow does not make a summer,' nor does one good deed make ethical behavior.”

“The availability of irrigation systems to water the land and produce grain and other food crops was the material foundation for these two great river-valley societies, Egypt and Iraq. They were hydraulic despotisms, in which a small ruling class, with the aid of soldiers and priests, commanded the material resources that gave sustenance to these civilizations and allowed them to build cities, palaces, and tombs.”

“Sacramental attachments to a dying a resurrected savior was a common idea in the Roman Empire. The religion of Mithraism, very popular in the army and open only to males, bathed the initiate in the blood of a bull.”

“While many Greeks (although not Thucydides) thought that history moved in circles, repeating itself infinitely, the Jewish idea that each event was singular and proceeded along a straight line had a great impact on European thinking.”