President Reagan is today's greatest threat to world peace because he is a afraid to try to win an arms race with the Soviet Union, a leading objectivist philosopher told a crowd of 75 students at Harvard Hall last night.

Peter Schwartz, publisher of the leading objectivist journal, The Intellectual Activist, said Reagan's current defense policy amounts to nuclear reduction through negotiation and "is the most immoral doctrine we could adopt."

Schwartz said that the military arsenals of the United States and the Soviet Union serve opposing purposes. "Our nuclear arsenal serves to preserve the freedom of the individual while the purpose of the Soviet arsenal is to annihilate the individual," he said.

"No amount of negotiation can reconcile our differences," said Schwartz. "The Kremlin wants to control and destroy human life. It can be a deadly mistake to believe that peace is in the Soviet interest.

"America is the policeman and Russia is the criminal," Schwartz added.

But Schwartz said he does not believe that the United States should try to destroy the Soviet Union. "Our only moral objective is to secure our own liberty. Our total nuclear superiority over the Soviets will assure this ideal," said Schwartz.

"Nuclear arms serve the distictly moral purpose of preserving human life," he said.

Schwartz's argument is based on objectivism, which holds that man is the supreme end, man's own happiness is the moral purpose of his life, and harmony will be reached through each individual's struggle for economic success, said Linda Reardan, a graduate student of philosophy and member of the Objectivist Club.

The Objectivist Club, which began last spring, sponsored Schwartz's speech and will present a speech on the root of terrorism in two weeks by Northrop Beuchen, Professor of Economics at St. John's University.