All teaching and all intellectual learning come about from already existing knowledge.

Memory is therefore, neither Perception nor Conception, but a state or affection of one of these, conditioned by lapse of time. As already observed, there is no such thing as memory of the present while present, for the present is object only of perception, and the future, of expectation, but the object of memory is the past. All memory, therefore, implies a time elapsed; consequently only those animals which perceive time remember, and the organ whereby they perceive time is also that whereby they remember.

If the poor, for example, because they are more in number, divide among themselves the property of the rich,- is not this unjust? . . this law of confiscation clearly cannot be just.

But the whole vital process of the earth takes place so gradually and in periods of time which are so immense compared with the length of our life, that these changes are not observed, and before their course can be recorded from beginning to end whole nations perish and are destroyed.

Friendship also seems to be the bond that hold communities together.

...The entire preoccupation of the physicist is with things that contain within themselves a principle of movement and rest.

The first essential responsibility of the state is control of the market-place: there must be some official charged with the duty of seeing that honest dealing and good order prevail. For one of the well-nigh essential activities of all states is the buying and selling of goods to meet their mutual basic needs; this is the quickest way to self-sufficiency, which seems to be what moves men to combine under a single constitution.