"Interior of a Church" by Emanuel de Witte. c. 1680. Collection: Cleveland Museum of Art. Image courtesy of Wikimedia Commons.
Realistic art is sometimes called “illusionist” or “illusionism.”* The term “illusionist” is often used to identify art that aims to re-create reality, but the term also implies that such art presents an illusion. Take the example of a painting that shows an interior of a room receding in the distance. According to the illusionist view of art, this kind of painting is thought to create an illusion of three-dimensional space where none exists — an attempt to lead the viewer to think that there’s a space within the picture frame where there is no such space.
The term “illusion” emphasizes the intent to represent something that does not exist: The viewer sees what appears to be a three-dimensional space, where he knows (or the artist knows) there is none — only a flat, two-dimensional canvas. The same charge of illusionism is applied to paintings of physical objects that accurately show the three-dimensional solidness of an object — an apple that looks like a solid orb resting on a surface, for instance, where we know there is no such apple, only paint on canvas.
“Illusionism” is also more narrowly applied to artworks that in some way use the space that the viewer occupies, or that seem to share the viewer’s space, such as a painting of a figure that seems to reach out to the viewer. This latter use of the term needs to be reconsidered, and perhaps abandoned. According to this use of the term, all art that accurately shows a spacial, three-dimensional world is illusionistic; and certainly all of sculpture could be deemed illusionistic.
More broadly, I think that the term “illusion” is misapplied to realistic art. Artworks do not aim to present illusions and artists are not illusionists. Art aims to re-create reality based on the artist’s observation of reality, and according to the artist’s outlook (on reality). It is not an attempt to trick the viewer into thinking that what the artist re-creates exists within the picture frame (an actual corridor or an apple). It is an attempt to re-create, or represent, some aspect of reality in a way that dramatizes the artist’s assessment of reality. The artist’s reliance on what he observes is basic to his grasp of, and assessment of, existence. It is not a ploy to impress or trick the viewer.
There is a type of art that is explicitly aimed at illusionism. That type of art is called “trompe l’oeil” (French for “deceives the eye”), and it was popular in the 17th and 18th centuries. Arguably, trompe l’oeil art aims at impressing or tricking the viewer into believing that something exists where it does not. That is a legitimate use of the term that distinguishes art that intends to impress or trick the viewer in some way.
But to conflate realist art per se with illusionism denies the basis and purpose of art.