PEOPLE IN THE People's Republic of China have been "eating from the same big pot" -- the description now given to the brand of socialism under which everyone gets more or less equal benefits, regardless of what he contributes to the common good. But now this is to end. Declaring that "socialism does not mean pauperism," the Communist Party has just extended a modified market system from the countryside, where it has been applied since 1978, to the urban industrial economy. "For a long time, people used to consider competition peculiar to capitalism," the party says. Reform is "the trend of our times."

The prospect is being greeted in some Western quarters as an achievement comparable to that of constructing the Great Wall. Certainly it is stunning to conplate the application of free-enterprise principles and methods to the largest and one of the poorest countries of the world. It suggests a historic recognition of the bankruptcy of the Stalin- type centralized command economy, which the People's Republic has relied on for its 35 years and the Soviet Union for its 67. To have capitalist principles validated as they have been in the Asian rim lands is one thing. Just to see a similar reform undertaken in China is big news.

Free-enterprise tub-thumpers, however, should be cautious. Tight Communist Party control remains the rule. The new reform reflects a "consensus view": misgivings remain. Its sponsor, Deng Xiaoping, is 80, which means that the perennially dominant issue in Chinese politics -- how to modernize -- may soon be up for argument again.

This is not the first time China has experimented with incentives and decentralization. Earlier, considerably less ambitious attempts foundered on the the Communist Party's reluctance to yield close central control, which has prevented similar, less vigorous efforts in the Soviet Union from even getting off the ground. There is also the continued vulnerability of a society claiming to be revolutionary to the charge that it is abandoning egalitarianism for the capitalist road. The few smaller and more advanced East European places where reform has been installed may not be good models for huge, traditional, backward China.

Still, if you had to bet on a socialist country that could make a go of a modified capitalism, China would be the one. Hong Kong and Taiwan do appear to demonstrate the compatibility of Chinese culture and free enterprise. A China with a system that had liberated the full energies and talents of its people, at least in the economic sphere, would be a formidable power on the world scene. The reform could yet become one of the major events of the end of the 20th century.