Nervous systemIn biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue first arose in wormlike organisms about 550 to 600 million years ago. In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS).
Stimulus modalityStimulus modality, also called sensory modality, is one aspect of a stimulus or what is perceived after a stimulus. For example, the temperature modality is registered after heat or cold stimulate a receptor. Some sensory modalities include: light, sound, temperature, taste, pressure, and smell. The type and location of the sensory receptor activated by the stimulus plays the primary role in coding the sensation. All sensory modalities work together to heighten stimuli sensation when necessary.
Philosophical zombieA philosophical zombie (or "p-zombie") is a being in a thought experiment in philosophy of mind that is physically identical to a normal person but does not have conscious experience. For example, if a philosophical zombie were poked with a sharp object, it would not feel any pain, but it would behave exactly the way any conscious human would. Philosophical zombie arguments are used against forms of physicalism and in defense of the "hard problem of consciousness", which is the problem of accounting in physical terms for subjective, intrinsic, first-person, what-it's-like-ness experiences.
