The article presents the principle when two forces applied from one side of the lever mechanism, for their mutual balancing, have one direction of their action. To implement this principle, it is necessary to bring the action of forces to their common support with the possibility of their movement in different directions relative to each other. The paper considers the case when two unidirectional forces compensate each other, since they have oppositely directed degrees of freedom. On this basis, a mechanism is proposed that belongs to flat hinged (lever) mechanisms, and which can be used in the design of industrial and lifting cranes. This principle will allow us to take a fresh look at dialectics, which will require presenting the struggle of two opposites as the summation of two one–sidedness (united actions) with diametrically opposed possibilities (rights freedoms, interests, ...).