Very few artists have had so extraordinary an effect upon the art of future generations as Cezanne had upon the art of the 20th century. Without him, painting today would be quite different, modernism would almost certainly be more informal, and Monet, Van Gogh, Sargent, and Munch would probably rank even higher in our minds than they already do.
Cezanne's influence has been both specific and subtle. Cubism, Fauvism, and Constructivism derive largely from particular perceptions of his art. Such painters as Matisse, Klee, Miro, Pollock, and Diebenkorn owe at least some of their creative identity to him or to those who drew their inspiration from his work.
Not even the art based upon pre-Impressionist formal ideals or a strict rendering of nature's appearances is totally immune. Almost all major 20 th-century ''realists'' were influenced to some degree by Cezanne's perceptions of space and color, and by his ideas on pictorial construction. His influence may not be obvious in such work, but just the same it is often there.
Major exhibitions of his work occur infrequently, however, mainly because such shows create nightmarish problems in logistics. Assembling a Cezanne exhibition from collections around the world is an extremely difficult and expensive undertaking.
The Philadelphia Museum of Art has a way out of that dilemma. It owns a large number of Cezannes - and can draw upon another large group owned by residents of Philadelphia and its environs.
''Cezanne in Philadelphia Collections'' is just such a fusion of museum and private collecting. Its 45 items include 28 works owned by the Philadelphia Museum and 17 owned by Philadelphia collectors. Together, they make up an exceptional cross section of Cezanne's art that includes his monumental canvas ''Large Bathers,'' some of his greatest landscapes and still lifes, a few excellent portrait studies, and a handful of outstanding drawings, watercolors, and prints.
It may not be the biggest Cezanne show ever assembled, but it is certainly one of the most beautiful and revealing I've seen in a long time. Seeing the ''Large Bathers'' ideally hung, then walking around the galleries among old favorites and some unknown works, was a very special treat.
This, I thought, is what painting is all about. I didn't so much look at paintings as feel myself drawn to participate in Cezanne's remarkably holistic vision. It was a vision that caused every brushstroke, line, form, texture, and color to make its precisely appropriate contributions to the final, overall effect. After an hour in those galleries, I felt more serene and at peace, more myself than I had in days. And I came away more certain than ever that Cezanne must be counted among the world's very greatest painters.
This ability to challenge the viewer to achieve deeper levels of integration and fulfillment, and then to lead that viewer toward such levels, is one of the surest tests of an artist's greatness. One experiences this challenge and realization before the art of Giotto, Masaccio, Michelangelo, Velazquez, Rembrandt, Vermeer, El Greco, Goya, and a handful of others. It's a potentially life-altering experience that not even genius can fake, for genius is only the raw material out of which greatness is occasionally fashioned.
Greatness is a quality of vision and a level of accomplishment that transcends style, subject, time, or technique. It cannot be artificially induced by brilliant verbiage or clever ideas. It has little to do with size, thematic importance, or type of material used. Some of the world's greatest works of art are no larger than a human hand, depict such simple things as apples or a few rocks and a tree, and were executed in chalk or wash on very ordinary paper.
In Cezanne hands, for instance, an arrangement of fruit and bottles on a colored tablecloth achieves the dignity and monumentality of a Poussin figure composition or a Vermeer interior. Nothing is petty in his world. Every leaf and stone, every fold in a napkin or curve in a vase, participates in his grand and ordered painterly vision.
And yet, nothing is forced in the process. Everything seems to have fallen naturally into place and to be doing its part in leading the viewer to a deeper and grander perception of his world and all that's in it.
The Philadelphia Museum and the private collectors of that city should be proud of their Cezannes - and of this exhibition. It's a beautiful show with a few special surprises. Chief among them is the stunning and quite Impressionistic ''Landscape: Isle de France,'' the remarkable early ''Hamlet and Horatio,'' and one of the loveliest Cezanne drawings I've ever seen, ''Girl Wearing a Fichu.'' I was also impressed all over again by his ''Portrait of Madame Cezanne'' and ''Large Bathers.'' Demuth as a bonus
There's an extra treat in store for the visitors to the Cezanne exhibition in the form of a small but excellent show of Charles Demuth's paintings and watercolors.
It is appropriate that the works of Cezanne and Demuth (1883-1935) can be seen during one museum visit, for a great deal of what the latter's work is all about derived from the art of Cezanne. Most of that influence may have been indirectly transmitted by Cubism and underscored by the work of John Marin and Marsden Hartley, but Cezanne's vision was the primary formal inspiration for his art.
This isn't to say that Demuth was not an extraordinary artist in his own right. His elegantly geometric paintings of urban architecture stand out in any exhibition of early 20th-century American art. And his illustrations and watercolors of fruit, flowers, and still lifes rank among this century's finest works on paper.
This exhibition includes excellent examples of all aspects of his work. It wil remain on view at the Philadelphia Museum through Sept. 11, and will then travel to the Heritage Center of Lancaster Country, Lancaster, Pa. (Oct. 1-Nov. 13), and to the Museum of Art, Carnegie Institute, Pittsburgh (Nov. 23-Jan. 22, 1984).