Impressionism: 

Impressionism is a late 19th century art movement interested in capturing the fleeting qualities of light, color, and atmosphere as well as the emerging psychological principles concerning human consciousness.  The movement is most widely associated with the paintings of Monet, Manet, Renoir, Cezanne, and Degas. We're interested in the because it offers a visual representation of the Modernist a break from Locke's empirical theory of knowledge: Impressionism represents the growing belief that the perception of reality that is mediated by personal emotion and memory. 

Taken as a whole, Impressionism argues that we don't really see the natural or "real" world objectively because everything that we perceive is filtered through our minds, and our minds are filled with unique and personal memories and emotions, so each of our minds perceives the world differently.  You might say that while Locke argued knowledge comes via "sensation and reflection," Modernists (and Post Modernists) argue that reflection shapes "senation" (sensory input) as it enters, so that we never really even see the natural world as it truly exists. 

We're also mainly interested in how Conrad borrows from this artistic philosophy in Heart of Darkness.

Modernism And Perception:

In many ways all Modern art focuses on this complex and often faulty relationship between reality and perception.  Modernists argue that our perception of reality is filtered thru a complex process, rather than the brain holding a "one-to-one" reflection of the objective/real world.
 

Psychology:  The movement grows directly out of the profound influence of Freud's theory that we're constantly reminded that our emotional and subconscious "clouds" our perceptions, and this is rooted in Rousseau's "I felt before I thought." Impressionism attempts to capture/represent psychological perception of experience; experience as perceived by the mind, not just the eye or an objective observer. See Freud Dreams.

Marx and Nietzsche:  Similarly, Marx argued our minds are simply full of Ideology, not facts or Truth, and these "cloud" our perception as much as emotion, making our understanding of morality and truth "hazy and "gray" rather than "black and white";  Nietzsche similarly argued morality is a cultural construction.

The Impressionists apply these concepts to our ability to perceive or capture in art even the "truth" about what we physically see, especially given how we perceive changing light and motion and then attempt to capture them on a static canvas.

We'll follow this dissolution of fact and reality even deeper in Post Modernism....

Heart of Darkness and Impressionism:

Conrad on the Impressionist influence on some of his work:

“Explicitness, my dear fellow, is fatal to the glamour of all artistic work, robbing it of all suggestiveness, destroying all illusion. You seem to believe in literalness and explicitness, in facts and also in expression. Yet nothing is more clear than the utter insignificance of explicit statement and also its power to call attention away from things that matter in the region of art.”       -- Conrad, letter to publisher 24 April 1922

“…a work of art is very seldom limited to one exclusive meaning and not necessarily tending to a definite conclusion. And this for the reason that the nearer it approaches art, the more it acquires a symbolic character. …the symbolic conception of a work of art has this advantage, that it makes a triple appeal covering the whole field of life. All the great creations of literature have been symbolic, and in that way have gained in complexity, in power, in depth and beauty. … But as to “final effect” my conscience has nothing to do with that. It is the critic’s affair to bring to its conclusion his own honesty, his sensibility and intelligence.”

Quotes from Heart of Darkness:

“In the offing the sea and the sky were welded together without a joint and in the luminous space the tanned sails of the barges drifting up with the tide seemed to stand still in red clusters of canvas, sharply peaked with gleams of vanishing spirits. A haze rested on the low shores that ran out to sea in vanishing flatness. The are was dark above Gravesend, and farther back still seemed condensed into a mournful gloom…” (1) (1491).

Parliament by Monet (1900-1904)

“We looked at the venerable stream (the Thames) not in the vivid flush of a short day that comes and departs for ever but in the august light of abiding memory” (8) (1492).

Sunrise by Monet (1872)

Also see: Impressionist Art

Also see: Freud Dreams