defining sensation as a mere internal experience and differentiating between the act of sensing and the judgment about the external world that accompanies it. Balmes presents examples, such as the perception of two identical frames, to illustrate that sensations can occur without a direct connection to external objects, which raises questions about the reliability of our senses. Furthermore, he argues that while animals perceive sensations, their understanding is limited, indicating a distinction between sensory experiences and true intelligence. Overall, the beginning of the book sets the stage for a deeper exploration of how sensations relate to knowledge, reality, and the distinctions between various forms of awareness. (This is an automatically generated summary.)