2. "I must study politics and war that my sons may have liberty to study mathematics and philosophy. My sons ought to study mathematics and philosophy, geography, natural history, naval architecture, navigation, commerce and agriculture in order to give their children a right to study paintings, poetry, music, architecture, statuary, tapestry and porcelain."
3. To his son John Quincy he said, "A taste for literature and a turn for business, united in the same person, never fails to make a great man."
4. McCullough wrote of Adams as an old man in his eighties, "The simplest, most ordinary things, that in other times had seemed incidentals, could lift his heart and set his mind soaring. The philosophy that with sufficient knowledge all could be explained held no appeal. All could not be explained, Adams had come to understand. Mystery was essential. 'Admire and adore the Author of the telescopic universe, love and esteem the work, do all in your power to lessen ill, and increase good,' he wrote in the margin of one of his books, 'but never assume to comprehend.'"
5. Adams further said, "I find my imagination, in spite of all my exertions, roaming in the Milky Way, among the nebulae, those mighty orbs, and stupendous orbits of suns, planets, satellites, and comets, which compose the incomprehensible universe; and if I do not sink into nothing at my own estimation, I feel an irresistible impulse to fall on my knees, in adoration of the power that moves, the wisdom that directs, and the benevolence that sanctifies this wonderful whole."