Alan Andres offers these notes on Michael Snow's Rameau's Nephew

Page 1046:
Snow's longest work to date, the more than four-hour 'Rameau's Nephew By Diderot (Thanks to Dennis Young) by Wilma Schoen,' which he began after his return to Toronto in 1971 and completed in 1974, marks a significant departure in his cinema. Snow described the film as a 'talking picture,' and this comment--coupled with his mention of the French encylopedist, philosopher, and author Diderot in the title--pointedly announced to audiences that the film would be encyclopedic and philosophical in the way that it inventoried and explored the nature of sound. Unlike his three major works of the sixties and seventies, Rameau's Nephew ...is not unified by a single visual strategy that creates a dominant perceptual shape. Rather, it consists of some twenty-five sections, significantly different in length. Each segment is a meditation--often comic--about the nature of recorded sound, both abstract and representational, about the many possible kinds of audiovisual relationships, and about their philosophical implications. According to Regina Cornwell [Snow Seen, 1980], running through the film, 'is a philosophical discussion about reality, appearance, illusion, representation, verisimilitude, which is undercut by humor in the form of sophisms, paralogisms, puns, repetition, variation, excess.' A single brief, but characteristic example from the sprawling work with its maze of internal cross-references will have to suffice: In the eighth sequence, we see Snow's hands drum an empty kitchen sink that gradually fills with water and then is emptied again. The episode is, of course, based on a verbal joke about "sync" or synchronized sound, the most familiar way that sound is used in film. This formulation of the idea in turn links up with a multitude of similar humorous experiments with synchronization in other sequences.

And from The International Dictionary of Films and Filmmakers Vol II, ed by Christopher Lyon:

'Rameau's Nephew'...takes on an encyclopedic range of topics related to picture and sound, with a Duchampian 'study' of language most prominent. For 285 minutes, in apparently 24 distinct sections, the film explores the human body as a source of sound. The inherent independence of the picture and sound in all films becomes the justification for the invention of a series of totally improbable environments born of the disembodiment of sound: someone plays a sink, a voice roves around a room filled with people, a male/female urinating context is grotesquely simplified, a chair guffaws wildly, a piano moans out an orgasm, and so on. Like all of Snow's major works, his longest takes a technical fact as the generating force for a wholly cinematic presentation of space.

dakar@pop3.portal.ca adds:

...... a few words on Michael Snow. He's a Canadian, born in 1929, who's had major showings across North America and is perhaps Canada's pre-eminint experimental artist. (He is an artist, not a filmmaker, just an artist who paints, sculpts, films, etc.). He is married to Joyce Wieland, also a very well known artist in Canada.
Snow's best known work is a rather pedestrian piece, a flock of Canadian geese. This larger than life canvas hangs (it's a mobile) in Eaton Centre, a huge multi-story mall in downtown Toronto. Eaton's dressed the geese up one Christmas with red bows and Snow sued. Snow won.