The unseen refers to what is not subject to direct observation by any of the five senses.
- opportunity cost
- the medical harm from gambling and pornography
- Newtonian action-at-a-distance
- the invisible hand
- Atomic Radiation
- prayer and its effects
- the nature of homing powers of fowl
- deterrence of crime by self-defense
Materialists, by focusing on only what is material, generally deny the existence of the unseen.