He seizes on a quote in The New Yorker last year by the photographer William Klein, who posited an opposition between what he calls ''goyish photography'' (the landscape school of Edward Weston and Ansel Adams) and ''Jewish photography'' (''funky'' urbanists like Weegee and Arbus).

Mr. Kozloff accepts this division of schools and argues that images of New York by Jewish photographers during the middle of the century tend to reveal a unique ''social tension,'' which is usually not found in the work of their non-Jewish colleagues. Wrestling with issues of cultural assimilation, Jewish photographers devoured New York with their cameras while at the same registering a sense that they stood apart.

''They present the city as formed instant by instant out of their impulsive responses,'' Mr. Kozloff writes. ''It is their improvised exchange with their subjects, not a kit of fixed and essential attributes, that distinguishes their work.''

He analyzes a street scene in Harlem by Helen Levitt from 1945 as an example of a fleeting transaction between ''an in-group and an observing stranger.'' In contrast, images by photographers like Abbott and Evans ''irradiate a sense of proprietary nonchalance when they picture the city.'' Jewish photographers, according to this theory, emphasize the idiosyncratic human gesture within an energized urban space; ''gentile photographers'' -- Mr. Kozloff's words -- prefer to emphasize the immutability of the city's architectural grids.

If the work is recognizably Jewish in style, it is overwhelmingly secular in content, Mr. Kozloff believes. These photographers rarely focus on identifiably religious iconography, he writes. Instead, they have often featured African-Americans in their work, an expression, he thinks, both of shared feelings of marginality and of the well-established social protest tradition in American Judaism. Mr. Kozloff presents the show as ''an argument among Jews'' about the value and limits of assimilation and belonging, even if the photographers themselves were unaware of such dimensions in their work.

It's a bold and novel thesis, at least in the context of photography, and not without dangers. By fracturing history along ethnic lines, Mr. Kozloff is walking into a fault zone of his own creation. Those who in the past sought to identify a distinct Jewish sensibility have sometimes had mischief, or worse, in mind. Even if such a sensibility exists -- as is commonly claimed in comedy, literature and musical theater -- looking for evidence of a photographic ''visual'' style in one ethnic group or nationality verges on folly. Photography, after all, is a technology that did not evolve out of any specific cultural or religious tradition.