The Human Being, Pain, and the Contingency of Existence: Book II

Part 2 of *The Human Being, Pain, and the Chance of Existence* deepens the question of how the human body responds to its environment. Part 2 distinguishes between sensory habituation, neurological processing, and immune response. A smell may barely be noticed after some time. The immune system, however, operates through different mechanisms. It can continue to recognize a specific protein and respond to it, even when a person experiences the environment as normal. Genetic predisposition also plays a role. Some people have a greater biological susceptibility to allergic reactions. This predisposition does not fully determine which response occurs, but, together with environmental factors, it forms the background in which sensitization may develop. Allergy is therefore not presented as a problem with a single cause. Ventilation, humidity, temperature, dust, air circulation, and duration of exposure may all influence the severity of a reaction. The same person may experience different symptoms under different circumstances.