Nobody is questioning Akio Morita's intelligence. It is hard to dispute the genius in a man who, as head of Sony Corp. in the 1950s, overcame sluggish sales of its bulky ''pocketable'' tape recorders by giving away shirts with oversized pockets.

But one wishes businessmen like Morita would stick to what they know: business. Instead, Morita has taken the opportunity afforded by a recent visit to Canada to offer his thoughts on broader questions of economic policy. His views are neither original nor profound, but they are illustrative of a peculiar prejudice that runs through much popular economic thinking.

It concerns the alleged indispensability of manufacturing to an economy. An extraordinary number of people seem to believe that wealth is created only in the process of making things - tangible, material goods - especially if it involves bashing metal. Services, if they have any value at all, are simply adjuncts to manufacturing.

For Morita, the wholesale shift of employment in Western economies into services, if not to be rolled back, has gone far enough. It is ''only manufacturing which creates something new, which takes raw materials and fashions them into products which are of more value than the raw materials they are made from,'' he said.

This sort of industrial cargo cult is one area in which we in North America have no difficulty competing with imports from Japan. ''What are our kids going to do,'' Walter Mondale complained in the 1984 U.S. presidential campaign, ''sweep up around Japanese computers?'' Chrysler Chairman Lee Iacocca warns ''we can't afford to become a nation of video arcades, drive-in banks and McDonald's hamburger stands.''

INTRINSIC WORTH

Hamburger-flipping has a special place in antiservices rhetoric. This ''structure snobbery,'' as the former Organization for Economic Co-operation & Development chief economist David Henderson calls it, is an example of a broader phenomenon: the doctrine of intrinsic worth, or as Henderson calls it, ''essentialism.'' For an economist, the value of an activity is measured by what people are willing to pay for it, at the margin.

For an essentialist, value is measured by inherent qualities thought to reside within the good itself, rather like the spirits in the rocks of animistic faiths. Thus the price of labor is said to depend on ''skill, effort, responsibility and working conditions,'' while oil is a resource so ''strategic'' it is divorced from all considerations of price whatever.

There is, of course, nothing to say one cannot subjectively value these and other goods according to any system one sees fit. The value of a work of art in aesthetic terms can hardly be measured by the price it fetches at auction. But when one is in the realm of economics, which is about co-ordinating everybody's subjective valuations, then price is the measure.

The singer or the teacher, the lawyer or the banker create economic value that is just as real as that of the automaker, so long as people are willing to trade the fruits of their own labors to acquire their services. Indeed, as a matter of economics a country need not have any manufacturing sector at all, if it can trade its resources or services with other countries for the goods it desires.

More sophisticated advocates of manufacturing worry that the shift into services involves a decline in productivity and hence our standard of living. It is certainly true that the average real wage in service industries is lower than in manufacturing. But that does not imply that real wages across the economy would be higher if we shifted employment back into manufacturing. To a large extent, wages are higher in manufacturing precisely because of all the jobs that have been created in services.

One of the great triumphs of the North American economies in recent decades has been their ability to accommodate an unparalleled mass entry into the labor market: the decision of millions of women at historically more or less the same time to go to work, rather than stay home.

Now that the adjustment is near completion, we will likely see a return to increasing productivity and real wages in the service sectors, as the capital-labor balance changes. We may even see employment tilting back toward manufacturing, as women acquire new skills and move from their services beachhead into traditional male preserves in manufacturing.