The Greeks had a word for the means in which art copies reality by observing nature, and that word was mimesis. It is a term used in philosophy and criticism. In current vernacular, we say "real".
Mimesis relegates art to a secondary status, then, as copy work, and the success or mastery is defined by how well the artist rendered a copy of the natural word. Again, we often say "realistic" as a defining term when we regard art.
That struggle over art as "truth", meaning that it is not truth but is a trick or a mime, led in large part to Art For Art's Sake and the quest for "pure art" in the 19th Century.
The Greeks gave us linear perspective which is a subjective way of rendering what we see. Keep in mind that this is SUBJECTIVE and depends on interpretation from a Point Of View (P.O.V.). In terms of truth and "reality", this is not real in a scientific sense. The road never actually narrows, and parallel lines remain parallel, they do not converge.
Other cultures, such as Japanese painting, and scientific approaches such as mechanical drafting for machine design, insist of the absoluteness of real measurements. This is called isometric perspective. This is OBJECTIVE. Parallel lines remain parallel and measurements remain constant.
A great deal of art is a trick. It plays upon our perceptions.
The invention of photography in 1828 brought the topic of truth to the forefront of art. At last, supposedly, light could make its own images. The subjectivity of the artist was removed. The image above was in William Henry Fox Talbot's book, The Pencil of Nature.
The camera and film could solve and settle many arguments, and a photograph may be used as evidence in court.
With the scientific study of the mind and personality in the 20th Century, psychoanalysis, a style of art came along that challenged our willingness to accept veracity and mimetic art. Rene Magritte's painting is titled The Treason of Imagery and mocks us through the phrase "Ceci n'est pas une pipe," meaning "this is not a pipe."
Salvador Dali's The Persistence of Memory was done in that Surrealist style. Generations of people have ascribed meaning to this painting when there isn't any meaning. Dali chose the trope of clocks and we project meaning. Like Alice following the rabbit down the rabbit hole because he has a timepiece and says "I'm late", we too think that there must be something important here when in truth there is nothing. Dali was in effect making it evident to us how our own subjectivity and projection can be tricked.