“There are, in fact, as I began to say above, not a few principles which are the special property of mathematics, such principles as are discovered by the common light of nature, require no demonstration, and which concern quantities primarily; then they are applied to other things, so far as the latter have something in common with quantities. Now there are more of these principles in mathematics than in the other theoretical sciences because of that very characteristic of the human understanding which seems to be such from the law of creation, that nothing can be known completely except quantities or by quantities. And so it happens that the conclusions of mathematics are most certain and indubitable.”

—  Johannes Kepler

Vol. VIII, p. 148
Joannis Kepleri Astronomi Opera Omnia, ed. Christian Frisch (1858)

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Johannes Kepler 51
German mathematician, astronomer and astrologer 1571–1630

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“If justice be not a natural principle, it is no principle at all. If it be not a natural principle, there is no such thing as justice. If it be not a natural principle, all that men have ever said or written about it, from time immemorial, has been said and written about that which had no existence. If it be not a natural principle, all the appeals for justice that have ever been heard, and all the struggles for justice that have ever been witnessed, have been appeals and struggles for a mere fantasy, a vagary of the imagination, and not for a reality.

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