As comprehensive a list as I can manage. If you can think of other additions, please feel free to leave a comment and I’ll approve it and consider it as I have time! If I’ve wrongly categorized anything as material or immaterial, let me know that too and I may update.
Black = unobservable and immaterial
Red = unobservable but not immaterial
- Absences of entities
- Afterlife or lack of afterlife
- Aliens (these might be observable one day, however)
- Appeal (like charisma)
- Artistic merit
- Chance or determinism
- Consciousness
- Constants in nature (observing effect isn’t the same as observing cause)
- Dark matter and dark energy
- Emergent properties
- Essences (in a mereological sense)
- Feel (for people without a sense of touch)
- Flavor (for people without a sense of taste)
- God (though some conceptions would claim God is observable)
- Gods (not all gods are immaterial)
- Importance and/or meaning and/or relevance
- Information
- Innovation
- Karma
- Laws of logic
- Laws of nature (see also constants in nature)
- Light (for blind people)
- Locations that a person has never observed and will always be incapable of observing (i.e. an elderly person on a deathbed may have never visited Antarctica, but still believes it exists)
- Morality
- Numbers (as universal framework)
- Other beings’ subjective personal experiences
- Other universes (“parallel” universes, “alternate” universes, etc.)
- Personality (see also laws of nature)
- Reality of the past (arguably material for people in the past, but unarguably immaterial for us)
- Reincarnation
- Sexual orientation (for asexual people—like me)
- Smell (for people without a sense of smell)
- Souls
- Sound (for the deaf, any sound that doesn’t create a visible physical vibration; for everyone else, any sound that doesn’t create a visible physical vibration and falls outside of a person’s hearing range)
- Spirits (ghosts, etc.)
- Symbolic expression and/or theme and/or thematic
- Time
- Value
Whether Christian or agnostic, these unobservable realities and possibilities have always fascinated me. Almost any one of them could probably justify its own post or post series of 2000+ words; I could talk about the Fermi paradox, David Hume, Alvin Plantinga, probability, Plato, near-death experiences, and so on in regard to their respective unobservable topics.
For now, though, I leave them listed without any further comment. Make of it what you will. =)
