"THE ONTARIO WAY with ideas is, in general, to regard ideas as orthodox or heretical, rather than as true or false," Royce MacGillivray writes in The Slopes of the Andes: Four Essays on the Rural Myth in Ontario (Mika Publishing, 192 pages, $35 cloth, $30 paper). If we believe him - and this unusual and fascinating volume helps to convince us to do so - no doubt Ontarians, and especially Ontario historians, would label MacGillivray`s book heretical. The title, from Moby Dick, is our clue: unlike most historical writings on English Canada, MacGillivray`s book blends memoir, impressionistic commentary, and historical observation about Canadian rural agricultural history. More conventional academics have trashed MacGillivray`s method, but readers eager to expand their cultural awareness will likely agree that the blend works. MacGillivray is no romantic. "These were scruffy towns full of no name brand dogs," he says of his home town, McCrimmon West, circa 1950. The 1960s, he reminds us, cast a glow over rural life, although from the early part of this century until then, farmers were generally looked down upon by society, often for good reason. As he goes on to explain, among the Canadian Scots "in early years the father ideally dominated his son by brute authority," and he speaks of the high rate of mental illness in many rural areas. MacGillivray`s comments on Canadian rural history are particularly enlightening, focusing on such diverse subjects as the effect of the introduction of meat into the daily diet of British Isles migrants, the ambivalence of farmers to forests, and the romanticization of the pioneer. At times the author is exceedingly funny, as, for example, in his witty and biting description of the ScottishCanadian family structure. Though some of the book`s historical observations may be questionable, this is history for the open-minded heretics among us.