WHETHER AMERICANbusiness rises to President Gorbachev's invitation and invests in the Soviet Union will depend largely on the Soviets themselves. It was an extraordinary appeal to foreign investors not only to come into his country but to take an active part in changing it. The Soviets, he told the corporate elite gathered to meet him in Minneapolis, "are ready to move resolutely toward the market." But that's precisely the point that they are going to have to establish more clearly before investment begins to flow on any substantial scale.

Mr. Gorbachev's country is going to be an inconvenient place to do business for many years, but inconvenience is not fatal. American business has put a lot of money into places where the transportation is uncertain, the hotels are bad and the phone service is worse. Those are things that can be expected to improve if the country genuinely chooses to open itself and become a part of the world market.

But before that can happen there are issues of principle that are going to have to be settled among the Soviets themselves. For all of the talk about market economics and reform, the reformers have not yet come to terms with the idea of private property. To dodge around those heavily freighted words, the government styles the small businesses now establishing themselves in great numbers as cooperatives. Even under that label they run into much harassment from the unreconciled old guard, which is numerous and not without power. Foreign investors will hesitate to put much money into the Soviet Union until they have better assurance that they can get their profits out. The present shortage of hard currency is compounded by a lingering ambivalence about the concept of profits.

Mr. Gorbachev acknowledged that many laws and many minds are going to have to be changed as the reforms go forward. There will be a lot of protests and demonstrations before the new ideas succeed, he conceded. But those American businesses that now come into the Soviet Union, he told the Americans, will have the government's cooperation in a land of unmeasurable potential -- while those who hesitate may be left outside forever.

The American response will exert a powerful influence in many other places -- most notably in Japan, with its huge surpluses to invest. But that response is going to be cautious. More American companies will certainly go into the Soviet Union, but boards of directors are likely to view these ventures as experiments, and highly tentative at that. Before serious money begins to move into the Soviet Union, foreign companies will want to see how the Soviets resolve the internal contradictions that the Gorbachev reforms are generating.