Date: w. c. 238

"Hence, the human heart-mind may be compared to a pan of water. If you place the pan upright and do not stir the water up, the mud will sink to the bottom, and the water on top will be clear and pure [qing ming] enough to see your beard and eyebrows and to examine the lines on your face."

— Xunzi (died after 238 BC)

Date: 1701, 1704

"The application of our Thoughts to other Subjects is like looking upon the Rays of the Sun as it shines to us from a Wall, or upon the Image of it as it returns from a Watry Mirrour, but this is looking up directly against the Fons veri lucidus, the bright Source of Intellectual Light a...

— Norris, John (1657-1712)

Date: 1737, 1743

"The best way to prove the clearness of our mind, is by shewing its Faults; as when a Stream discovers the Dirt at the bottom, it convinceth us of the transparency and purity of the Water."

— Pope, Alexander (1688-1744)

Date: 1751, 1777

"They [cruel ideas] still haunt his solitary hours, damp his most aspiring thoughts, and show him, even to himself, in the most contemptible and most odious colours imaginable."

— Hume, David (1711-1776)

Date: March 13, 1847

"As the sea, when it lies clam and deeply transparent, yearns for heaven, so may the pure heart, when it is calm and deeply transparent, yearn for God. As the sea is made pure by yearning for heaven alone; so may the heart become pure by yearning only for the Good. As the sea mirrors the elevatio...

— Kierkegaard, Søren (1813-1855)

Date: August-November, 1871

"[B]ut the mind of Mr. Rossetti is like a glassy mere, broken only by the dive of some water-bird or the hum of winged insects, and brooded over by an atmosphere of insufferable closeness, with a light blue sky above it, sultry depths mirrored within it, and a surface so thickly sown with water-l...

— Buchanan, Robert (1841–1901)

Date: 1925

"A man of action is likely to be a poor thinker, if a thinker at all, while the ideal of the sage, the stoic for instance, is to live detached and to keep his soul motionless like a still lake which impassively mirrors the fleeting skies."

— Ortega y Gasset, José (1883-1955)