SENSE

Sense refers to the faculties by which organisms detect environmental or internal stimuli and form perception. In humans, the traditional framework identifies five sense organs corresponding to sight, hearing, touch, taste, and smell. Sensation is the transduction of physical or chemical energy into neural signals, while perception is the brain’s interpretation of those signals.

Vision relies on photoreceptors in the retina; hearing on hair cells in the cochlea; touch on mechanoreceptors in skin; taste on taste buds; and smell on olfactory receptors in the nasal epithelium. Many researchers also recognize additional senses such as proprioception (body position), vestibular sense (balance), nociception (pain), thermoreception (temperature), and interoception (internal states). The term “sixth sense” is informal and varies in meaning across contexts.

Signals travel via peripheral nerves to the brain; for most senses they reach the thalamus before projecting to primary sensory cortices (visual, auditory, somatosensory). The brain integrates information across modalities in higher-level areas to produce a coherent percept of the surrounding world.

Species vary in their sensory capabilities. Animals may possess specialized receptors for light, electric fields, magnetic fields, or air movement, reflecting ecological needs and evolutionary history. Perception is thus a combination of available sensory input and neural processing.

In linguistics and philosophy of language, sense can also denote the semantic content of a term or proposition—the way its meaning is understood—distinct from its reference. In technology, sensors extend sense to machines, allowing devices to detect light, sound, chemicals, pressure, and other data to infer states and guide actions.