What is commonly referred to as the "seat of the pants" sense?

The "seat of the pants" sense refers to the awareness of one's body's position and movement in space, primarily through the somatosensory system. This system encompasses various sensory modalities that provide information about body sensations, including proprioception (the sense of body position) and tactile feedback from the skin.

When an individual experiences changes in their body posture or movement, the receptors in the muscles, joints, and skin transmit this information to the brain, allowing for a sensation of how the body is oriented and moving. This system is essential for maintaining balance and coordinating movement, particularly in environments where visual cues may be insufficient or absent, such as during flight.

The other systems, while they do contribute to overall sensory awareness, do not specifically provide the tactile feedback and proprioceptive information that the somatosensory system offers. Thus, it is the somatosensory system that is most accurately described as the "seat of the pants" sense, as it allows individuals to "feel" their position and movement in a direct and intuitive way.