Feeling pain requires specific neural architecture that fish lack. While humans readily attribute subjective experience to animals that respond to noxious stimuli, the neural properties necessary for phenomenal consciousness—the subjective feeling of sensory stimuli—are present in mammals and birds but absent in fish. Fish respond to noxious stimuli reflexively and with limited behaviors, not through conscious awareness. The paper proposes a set of fundamental neural tissue properties required for experiencing affective states and concludes that fish do not feel pain.
Placebos are typically seen as ineffective treatments because they lack a known mechanism linking their properties to the condition being treated, yet they can produce substantial therapeutic effects. This puzzle arises from the relationship between culturally meaningful entities like treatments, our intentional attitudes such as beliefs about healing, and bodily placebo responses. An enactive conception of cognition, which views an organism's adaptive bodily processes, its intentional directedness, and meaningful environmental properties as co-emergent aspects of a single dynamic system, accommodates and demystifies placebo effects by explaining the interrelations between mind, body, and world.