The text discusses the concept of contradictions and how they play a role in various aspects of society and technical systems. The enlightener is criticized for not acknowledging the inherent contradictions within social development. In the context of imperialist wars, guerrilla strategies aim to sharpen these contradictions. The global economy experienced a revival in the 50s due to various factors. The law of contradiction in things is a fundamental principle in dialectics, according to Lenin. In terms of blade grinding, precision and technique are key for achieving sharpness. Successful sharpening requires understanding the type of blades and proper use of the machine. The article touches on physical contradictions in the evolution of technical systems, which occur when trying to improve one characteristic but having a negative impact on another.