Demonstration is also something necessary, because a demonstration cannot go otherwise than it does, ... And the cause of this lies with the primary premises/principles.

Of governments there are said to be only two forms - democracy and oligarchy. For aristocracy is considered to be a kind of oligarchy, as being the rule of a few, and the so-called constitutional government to be really a democracy.

Thinking is different from perceiving and is held to be in part imagination, in part judgment

The man who confers a favour would rather not be repaid in the same coin.

The body is most fully developed from thirty to thirty-five years of age, the mind at about forty-nine.

For suppose that every tool we had could perform its task, either at our bidding or itself perceiving the need, and if-like the statues made by Dædalus or the tripods of Hephæstus, of which the poet says that "self-moved they enter the assembly of the gods" - shuttles in a loom could fly to and fro and a plectrum play a lyre all self-moved, then master-craftsmen would have no need of servants nor masters of slaves.

You should never think without an image.