The stone added in my mind was related to my previous practice effect, which was related to the stone of the objective world. Because it tripped me over, I added a stone to my mind. However, this connection is neither direct nor inevitable. Maybe I didn't see the stone after I fell once. Maybe it was dark, or I had bad eyes. At any time, the only thing that affects my decision is the stone in my mind. The stones of the objective world will not directly affect my decision-making. If the stone has been removed, I don't know, then I will be very careful when I go there. Because I still have that stone in my mind.
This is an important difference between Dialectical Dualism and Materialism. Since the objective existence of the material can not affect my decision, so we can keep silent about the objective existence, not to describe the objective world. We only need to describe the objective world in our heads, because it's the objective world in our heads that affects our decisions. The scientific worldview attempts to describe the objective and real world, while the philosophical worldview should describe the world that affects decision making. The philosophical world view is a fake world view, but it is more valuable than the real world view because it describes the world view that affects decision-making. The real objective world is not a part of the subjective world, the objective world in the mind is a part of the subjective world. The objective world in the mind and the subjective world are mutually contained dialectical unity.
Karl Marx regarded practice as the core concept of philosophy, everything starts from practice, all theories should serve for practice, this view is wrong. All theories should serve for decision making.
If practice is successful, it can bring benefits to people, so we all hope that practice can succeed. Man can rule the world because his practice is better than that of animals. The success of practice depends on two factors: decision making and objective material conditions. Apart from these two factors, nothing else can affect the effect of man's practice. Decisions belong to the subjective world and material conditions belong to the objective world.