THE MORE you think of it, the more astonishing it is that until just the other day there had apparently been no violence in Poland in the seven months since the workers' movement flowered last August in Gdansk. A thousand times, tempers must have been so frayed and the stakes must have seemed so high that one side or the other could easily have taken a step that would have ended in a bloody confrontation. Such has been the restraint and discipline on both sides, however, that this emotion-laden struggle for power in Poland has been conducted in a non-violent style. The workers have been careful to deny the government pretexts to bring its police powers to bear. The government has wisely refrained form provoking forceful showdowns; though some officials must have been solely tempted, others must have realized that the ultimate bankruptcy of a party claiming to rule in the name of the workers is to do violence to them. The Polish revolution has to be recorded as one of the great passages of non-violent change -- so far.

Precisely here lies the ominous importance of the incident that took place in Bydgoszcz, a city midway between Warsaw and Gdansk, last Thursday evening. The known details are obscure, but apparently the police came out swinging and some Solidarity members and sympathizers ended up with broken heads. Instantly, it appears, Solidarity knew it had another national crisis on its hands, and it started to unsheathe the major weapon the workers' movement has available to it, a strike. It did this nonwithstanding its pledge last month to give the new prime minister the initial 90-day strike-free period he had sought. Instantly, too, the government knew it had a crisis on its hands, and moved to distance itself from whatever the "local" authorities had done in Bydgoszcz. By yesterday, high-level government union talks had begun, the evident short-term purpose being to calm the situation down and the apparent long-term purpose being to work out arrangements, or at least procedures of consulation, to prevent similar incidents in the future.

It was a clear demonstration of the workings of the two-party system that has come to be a reality in Poland since August. The Communist Party-led government cannot rule without the workers: It must consult them to make the economy work, and it must now consult with them on the terms on which the state defines and administers the law. The Catholic Church, meanwhile, has emerged as a guarantor of the new system. Cardinal Wyszynski, using the church's easy new access to the national media, yesterday urged caution on the authorities and patience on the people. These are the difficult and mutuall obligations that the new order requires.

It is high drama but, of course, the denouement is unknown. Each new crisis that hits Poland tests the strength of its new system seemingly to the limit. Each time a crisis is survived, it adds experience, confidence and resiliency to the revolution, gives it duration, confirms the evident fact that the Poles are competent to handle their own affairs and in that way diminishes the grounds on which the Soviet Union could claim a right to intervene.

At the same time, each time a crisis is survived it contributes to a cumulative brooding sense in Poland that the convolutions and shocks of the revolution are virtually unending. This is a factor of fatigue and debilitation. Each such crisis, moreover, customarily ends in at least a partial victory for Solidarity. This may be where justice lies, but it is also where danger lies. "I told [the prime minister] Solidarity did not want strikes because we do not wish to finish each other off," Lech Walesa said on Saturday in an exact and typically blunt allusion to the dependent relationship that has come to exist between the two sides in Poland.