The shift from Impressionism to Post-Impressionism represents a fundamental change in the conceptualization of the artist's role. While Impressionists sought to capture the fleeting effects of light and atmosphere through spontaneous brushwork, Post-Impressionists like Paul Cezanne and Georges Seurat felt this approach lacked structural rigor. Cezanne, in particular, argued that painting should be a harmony parallel to nature, emphasizing geometric forms and the underlying permanence of objects rather than their momentary appearance. This transition was not merely aesthetic but philosophical, marking a move toward personal expression and away from the objective recording of visual stimuli. By abstracting reality, these artists paved the way for the radical subjectivity of the twentieth century, transforming the canvas from a window into a world into a self-contained exploration of form and color. Critics at the time were often bewildered, labeling the work as crude or unfinished, failing to realize that the lack of traditional finish was an intentional rejection of nineteenth-century academic realism.