“The greatest and noblest conceptions have no image wrought plainly for human vision, which he who wishes to satisfy the mind of the inquirer can apply to some one of his senses and by mere exhibition satisfy the mind. We must therefore endeavor by practice to acquire the power of giving and understanding a rational definition of each one of them; for immaterial things, which are the noblest and greatest, can be exhibited by reason only, and it is for their sake that all we are saying is said. But it is always easier to practice in small matters than in greater ones.”
285e-286b
Statesman
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Plato 80
Classical Greek philosopher -427–-347 BCRelated quotes

Preface
The History and Present State of Electricity (1767)
Context: The history of philosophy enjoys, in some measure, the advantages both of civil and natural history, whereby it is relieved from what is most tedious and disgusting in both. Philosophy exhibits the powers of nature, discovered and directed by human art. It has, therefore, in some measure, the boundless variety with the amazing uniformity of the one, and likewise every thing that is pleasing and interesting in the other. And the idea of continual rise and improvement is conspicuous in the whole study, whether we be attentive to the part which nature, or that which men are acting in the great scene.
It is here that we see the human understanding to its greatest advantage, grasping at the noblest objects, and increasing its own powers, by acquiring to itself the powers of nature, and directing them to the accomplishment of its own views; whereby the security, and happiness of mankind are daily improved. Human abilities are chiefly conspicuous in adapting means to ends, and in deducing one thing from another by the method of analogy; and where may we find instances of greater sagacity, than in philosophers diversifying the situations of things, in order to give them an opportunity of showing their mutual relations, affections, and influences; deducing one truth and one discovery from another, and applying them all to the useful purposes of human life.
If the exertion of human abilities, which cannot but form a delightful spectacle for the human imagination, give us pleasure, we enjoy it here in a higher degree than while we are contemplating the schemes of warriors, and the stratagems of their bloody art.

An Old Man's Thoughts on Many Things, Of Education I

Source: Think and Grow Rich: The Landmark Bestseller - Now Revised and Updated for the 21st Century

James Martin (1993, p. 17) as cited in: " CIS330 Object Oriented Approach Ch2 http://webcadnet.blogspot.nl/2011/04/cis330-object-oriented-approach-text_3598.html" webcadnet.blogspot.nl. 2011/04/16

Preface to A Thurber Garland (1955)
From other writings

Source: Psychology: What it has to Teach You about Yourself and Your World (1924), p. 83