“In a word, the opinions of learned authors, though their bodily forms are absent, gain strength as time time goes on, and, when taking part in councils and discussions, have greater weight than those of any living men.”
Introduction, Sec. 17
De architectura (The Ten Books On Architecture) (~ 15BC), Book IX
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Vitruvius 203
Roman writer, architect and engineer -80–-15 BCRelated quotes

Source: Letter to Lord Northbrook (12 June 1874), quoted in S. Gopal, British Policy in India, 1858-1905 (Cambridge University Press, 1965), p. 104.
Source: Interest and Inflation Free Money (1995), Chapter Three, Who Would Profit From a New Monetary System?, p. 67

Inaugural Address Delivered to the University of St. Andrews, Feb. 1st 1867 (1867) p. 36. http://books.google.com/books?id=DFNAAAAAcAAJ&pg=PA36
Source: Inaugural Address Delivered to the University of St Andrews, 2/1/1867
Context: What is called the Law of Nations is not properly law, but a part of ethics: a set of moral rules, accepted as authoritative by civilized states. It is true that these rules neither are nor ought to be of eternal obligation, but do and must vary more or less from age to age, as the consciences of nations become more enlightened, and the exigences of political society undergo change. But the rules mostly were at their origin, and still are, an application of the maxims of honesty and humanity to the intercourse of states. They were introduced by the moral sentiments of mankind, or by their sense of the general interest, to mitigate the crimes and sufferings of a state of war, and to restrain governments and nations from unjust or dishonest conduct towards one another in time of peace. Since every country stands in numerous and various relations with the other countries of the world, and many, our own among the number, exercise actual authority over some of these, a knowledge of the established rules of international morality is essential to the duty of every nation, and therefore of every person in it who helps to make up the nation, and whose voice and feeling form a part of what is called public opinion. Let not any one pacify his conscience by the delusion that he can do no harm if he takes no part, and forms no opinion. Bad men need nothing more to compass their ends, than that good men should look on and do nothing. He is not a good man who, without a protest, allows wrong to be committed in his name, and with the means which he helps to supply, because he will not trouble himself to use his mind on the subject. It depends on the habit of attending to and looking into public transactions, and on the degree of information and solid judgment respecting them that exists in the community, whether the conduct of the nation as a nation, both within itself and towards others, shall be selfish, corrupt, and tyrannical, or rational and enlightened, just and noble.

“It takes a long time to learn to live — by the time you learn your time is gone.”
Source: I Want to be a Mathematician: An Automathography (1985)

“A philosopher who is not taking part in discussions is like a boxer who never goes into the ring.”
Conversation of 1930
Personal Recollections (1981)