1. in Kantian philosophy, a thing as it exists independently of human perception, unknowable through the senses
Usage: philosophy; technical

Examples

• Kant argued that we can never know the noumenon directly.
• The noumenon exists beyond our sensory experience.
• Philosophy students often struggle with the concept of the noumenon.
• The distinction between phenomenon and noumenon is central to Kant’s theory.
• According to Kant, the noumenon is the reality behind appearances.
• We can only perceive phenomena, never the noumenon itself.