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Plato 80
Classical Greek philosopher -427–-347 BCRelated quotes

“There are many things that seem impossible only so long as one does not attempt them.”
Si le grain ne meurt [If It Die] (1924), ch. III
Source: Autumn Leaves

Philosophiae Naturalis Principia Mathematica (1687), Scholium Generale (1713; 1726)
Context: But it is not to be conceived that mere mechanical causes could give birth to so many regular motions: since the Comets range over all parts of the heavens, in very eccentric orbits. For by that kind of motion they pass easily through the orbs of the Planets, and with great rapidity; and in their aphelions, where they move the slowest, and are detain'd the longest, they recede to the greatest distances from each other, and thence suffer the least disturbance from their mutual attractions.
Source: Building Entopia - 1975, Chapter 12, Metropolis, p. 171

Source: Globalization - A Basic Text (2010), Chapter 5, Neo-Liberalism and Neo-Marxian Alternatives, p. 110

Source: How to Pay for the War (1940), Ch. 1 : The Character of the Problem
George A. Kelly, "Man's construction of his alternatives." Assessment of human motives (1958): 33-64.