“It is a beautiful truth that all men contain something of the artist in them. And perhaps it is the case that the greatest artists live and die, the world and themselves alike ignorant what they possess.”
"Talk to an Art-Union (A Brooklyn fragment)" http://www.aol.bartleby.com/229/4011.html (1839); later delivered as a lecture at the Brooklyn Art Union (31 March 1851) and printed in the Brooklyn Daily Advertizer (3 April 1851)
Context: It is a beautiful truth that all men contain something of the artist in them. And perhaps it is the case that the greatest artists live and die, the world and themselves alike ignorant what they possess. Who would not mourn that an ample palace, of surpassingly graceful architecture, fill’d with luxuries, and embellish’d with fine pictures and sculpture, should stand cold and still and vacant, and never be known or enjoy’d by its owner? Would such a fact as this cause your sadness? Then be sad. For there is a palace, to which the courts of the most sumptuous kings are but a frivolous patch, and, though it is always waiting for them, not one of its owners ever enters there with any genuine sense of its grandeur and glory.
I think of few heroic actions, which cannot be traced to the artistical impulse. He who does great deeds, does them from his innate sensitiveness to moral beauty.
Help us to complete the source, original and additional information
Walt Whitman 181
American poet, essayist and journalist 1819–1892Related quotes

“The beauty other people create is not for the artists. Artists have to live alone.”
1960's, Conversations with Samuel Beckett and Bram van Velde' (1965 - 1969)

“The greatest artists have never been men of taste.”
The Energies of Art: Studies of Authors Classic and Modern (1956)
Context: The greatest artists have never been men of taste. By never sophisticating their instincts they have never lost the awareness of the great simplicities, which they relish both from appetite and from the challenge these offer to skill in competition with popular art.

Introductory poem.
Poems (1869)
Context: This is a haunted world. It hath no breeze
But is the echo of some voice beloved:
Its pines have human tones; its billows wear
The color and the sparkle of dear eyes.
Its flowers are sweet with touch of tender hands
That once clasped ours. All things are beautiful
Because of something lovelier than themselves,
Which breathes within them, and will never die. —
Haunted,—but not with any spectral gloom;
Earth is suffused, inhabited by heaven.

“The function of the modern artist was not to convey beauty, but to convey new truths.”
The Age of Insight (2012)

Conclusion
Physics in my generation (1956)
Context: The scientist's urge to investigate, like the faith of the devout or the inspiration of the artist, is an expression of mankind's longing for something fixed, something at rest in the universal whirl: God, Beauty, Truth.
Truth is what the scientist aims at. He finds nothing at rest, nothing enduring, in the universe. Not everything is knowable, still less predictable. But the mind of man is capable of grasping and understanding at least a part of Creation; amid the flight of phenomena stands the immutable pole of law.
On becoming an artist in “‘There’s No Diploma in the World That Declares You an Artist’: Watch Kara Walker Lay Out Her Advice for Art Students” https://news.artnet.com/art-world/watch-kara-walker-art-21-1316030 in artnetnews (2018 Jul 12)