Marxism is always open, always critical, always self-critical.

Workers do not strike every day, they cannot do that the way they function in the capitalist economy. The way they have to live by selling their labor power makes that impossible.

Mistakes in themselves are unavoidable.

There is a process of social and of political differentiation going on in the real working class all the time.

And you cannot have a socialist revolution commandeered from the top, ordered around by some omniscient leader or group of leaders

You cannot make a socialist revolution without really trying.

The more workers you have in your organization, the better you are implanted in the working class, the more likely you are to come up with the concrete problems of the class.