This reflection focuses on a critical analysis of the concept of "acting" or "influence," which, particularly under the influence of mechanics, is often hollowed out and used in situations where a specific agent is absent. The author challenges the notion of acting as a mere external environmental influence or a one-sided mechanical act. Instead, he emphasizes that true action requires interaction between an actor and a responding subject. Using the example of infection, he demonstrates that a disease is not caused solely by the presence of a pathogen but arises through the active immune response of the attacked organism. Acting, therefore, becomes real only at the moment the subject responds to it. The text rejects simplistic causal schemes and proposes viewing the relationship between cause and effect as a dynamic process of mutual influence. This reflection opens up space for a deeper understanding of the relationship between activity and passivity in both natural and social processes, highlighting the constitutive role of subjectivity in every act of interaction.