The buzzword for the fall art season is ''connoisseurship.'' Museum exhibitions in New York address a broad spectrum of art history, from Old Masters to rebellious Beatniks. The goal is to train the viewer's eye with side-by-side comparisons of real and fake masterpieces, expand awareness of seldom-seen artworks, and evaluate an entire cultural movement. Real versus fake The Metropolitan Museum of Art offers two exhibitions that compare accepted masterpieces with paintings now ''de-attributed.'' In other words, fakes. ''Goya at the Metropolitan'' presents more than 300 works from the museum's collection, from drawings to oils. The show contrasts, for example, the popular painting ''Majas on a Balcony,'' which is of doubtful authenticity, to a verifiable Goya from a private collection. Also on display are Goya's print cycles in their entirety, such as ''The Disasters of War'' with its harrowing images of brutality. A month later the Met does it again, with ''Rembrandt/Not Rembrandt.'' Paintings, drawings, and prints by Rembrandt and his wannabe pupils and imitators hang cheek by jowl, challenging the viewer to discern and judge. Only about half - or around 20 - of the Met's ''Rembrandts'' have been confirmed by the Rembrandt Research Project, which has been striking terror into the hearts of curators the world over. The hit of the fall season is likely to be a show in an entirely different vein, ''Beat Culture and the New America: 1950-1965,'' at the Whitney Museum of American Art. The show examines the Beat generation's cultural legacy through more than 200 objects from this explosive period of artistic ferment. The multidisciplinary show highlights writers such as Jack Kerouac, Allen Ginsberg, and William Burroughs; independent films such as Robert Frank's ''Pull My Daisy,'' jazz musicians including Charlie Parker, and artists such as Larry Rivers, Robert Rauschenberg, and John Chamberlain who shared the Beat sensibility. More from these artists is at other venues. Rauschenberg will occupy the downtown Gagosian Gallery with new paintings on metal. Ginsberg shows his captioned portraits of buddies like Paul Bowles, Burroughs, and Gregory Corso in a lovely exhibition of photographs at the Tibor de Nagy Gallery. All the lonely people Overlapping the Beat show at the Whitney is a retrospective of Robert Frank's photographs, which opened at the National Gallery in Washington and will travel to Los Angeles's Lannan Foundation next spring. Known for his legendary book, ''The Americans'' (1959), the Swiss-American photographer punctured Eisenhower-era complacency with his tense images of lonely men and women - a quintessential Beat critique. Another photography show worth a look is ''Alfred Stieglitz at Lake George'' at the Museum of Modern Art. In 93 black-and-white photos from 1914-36, Stieglitz, a champion of modernism, presents not only his favorite subject - his wife, Georgia O'Keeffe - but also stunning landscapes and cloud studies he called ''Equivalents.'' Traveling shows that arrive in Manhattan this fall include ''John Singleton Copley in America,'' which originated at the Museum of Fine Arts in Boston. Seventy-five portraits of colonial merchants and patriots like Paul Revere by America's first great painter will be exhibited at the Met before traveling to Houston and Milwaukee in 1996. Mondrian's studio The Museum of Modern Art welcomes a big survey of the Dutch abstract painter Piet Mondrian. One hundred sixty paintings and drawings shown earlier at the National Gallery trace Mondrian's evolution from a figurative artist to a grandee of the grid. It also displays a reconstruction of Mondrian's studio, decorated, of course, with rectangles in primary colors on white. (The Monitor's full review appeared June 22.) The Solomon R. Guggenheim Museum hosts a survey of works by Pop sculptor Claes Oldenburg - which also started at the National Gallery - will travel to Bonn and London in 1996. (See the Monitor's full review, which appeared April 6.) More than 200 works by the artist who gave the world a soft-sculpture toilet and a plaster hamburger capture what Oldenburg calls the ''excruciatingly banal.'' An exhibition of exquisite Japanese screens from an important private collection in Tokyo, the Idemitsu Museum of Arts, premieres at the Asia Society before traveling to the Art Institute of Chicago. At an extreme level of purity, 57 screens from the 15th to 19th century depict flora and fauna in a surprising range of styles. The screens offer a window into Japanese painting that Westerners rarely experience. The National Academy of Design brings two turn-of-the-century Norwegians to town - ''Edvard Munch and Harald Sohlberg: Landscapes of the Mind.'' Maybe it's those long winters that caused these two Symbolists to dwell on the darker side of life. Angst, solitude, melancholy, and longing are the common themes in these haunting paintings and drawings. Given the diminished state of public funding for the arts, the 1995 art season will not be (to borrow the title from Munch's most famous work) a ''scream.'' Yet, with the absence of blockbusters and the attendant hype, these discriminating exhibitions may inspire museumgoers to think, feel, and reexamine.