One might say Monet's series on the Rouen Cathedral was a collection of paintings of sunlight. By focusing on the changing effects of sunlight on subject matter, his paintings became about capturing sunlight (if that makes sense). He painted the west façade of the Rouen Cathedral in northern France much like his haystacks, at different times of day and in different lights. Because he could not walk around the giant church as easily as the small haystacks in the empty field, he painted from almost the exact position each day; so the view of the church never changes. In that sense, Monet recreated the same painting over and over again, never changing either subject matter or perspective. But the paintings all differ, of course, because the changing sunlight and atmosphere of the air greatly affect the look of the building. Sometimes clear, other times enshrouded in fog; sometimes bright in noon-time light, other times fading into the darkness of dusk—the series shows nearly every imaginable lighting of the church, and yet Monet was revealing that an object can never be exhaustively painted; that it will always be different, always changing. He painted over thirty canvases just of this subject alone, and yet if we went to the Rouen Cathedral today it might still look distinct from any one of these paintings. The sunlight's effect might be totally new each and every day inasmuch as no two days are identical to each other. The subject matter will be the same, the church will not have changed, but it will appear different; and, what is more, our experience of it will be unique to the moment. And if these paintings really are of sunlight, the intangible daylight that characterizes our routine lives, then Monet is showing us that it is never the same, never as constant as we think it is, and therefore perhaps never fully understandable.
We have seen great works of art depicting vast landscapes and grandiose historical, mythological, and biblical scenes of heroes, warriors, saints, and kings. The ideas conveyed in these works have all contained a mighty profundity of their own, ranging from themes of good and evil, life and death, joy and grief, love and hatred. And we've seen portraits showing many memorable faces, thinking those, too, were poignant to look at. But this, now, is a game changer. Impressionism, more than any other artistic movement we have looked at thus far, deconstructs the nature of artistic subject matter in paintings and calls for a completely reverted approach to art theory—almost like going back to the beginning, but really going back further. All those great subjects in the paintings we saw—and yet now artists like Claude Monet paint a mere building thirty times, trying to capture the way the sun looks, and claim that even that isn't enough. By painting such a basic subject so many times, the artist seems to express the revelation that we can't even fully grasp a single photon of light, let alone the majestic works of saints and martyrs. Within the minutiae, the apparently small and inconsequential universe, there is inexpressible complexity. That an entire movement of artists should choose to focus on the elementary theme of sunlight—something we see around us every day of our lives, something as commonplace as air itself—just goes to show the extent of the Modernist perspective, that we, in a way, had to reintroduce ourselves with the world. After the Industrial Revolution, artists reverted back to studying these types of things and saw that the world itself is always changing and always blending in and out of new lights.