The Three Worlds
30th May 2020
Reading Time: 8 minutes
Suppose a dear friend comes to you one day in obvious distress. They've witnessed a terrifying apparition, they say. The spectral visitor appeared in their home the night before, frightening them terribly. What's more, your friend is convinced that the spirit always appears in the same room, wailing mournfully, precisely at the stroke of midnight. They beg you to spend the night at the house, to see the haunting for yourself.
Out of concern for your friend's seemingly genuine distress, you agree to hold vigil with them overnight. Armed with flashlights and healthy snacks, you comfort your friend as the appointed time approaches. Whether you have any belief in ghosts generally or not, your friend seems obviously distressed and in need of your good company. Perhaps you resolve to keep an open mind, just in case something unexpected should happen.
Aside from just being there for your friend in their time of need, the main thing you're wondering is: does the ghost exist? In order to answer that, you'll need to have a working definition of what exist means. Philosophers categorize questions about existence to a branch of metaphysics called ontology. Ontology explores the question of what exists and what doesn't, and whether there are different types of existence. Many different views have been proposed over the centuries, but the one that makes the most sense to me is Karl Popper's Three Worlds.
To illustrate the Three Worlds idea, let's consider three different ways your night in the haunted house might pan out:
Scenario One: exactly as the clock strikes twelve, a ghost appears, just as your friend described! Astonished, you quickly start recording a video of the wailing spirit, complete with its mournful cries. You discover that if you move around the room, you can view the phantom from different angles; it clearly occupies a specific location in the room and has three-dimensional volume and form. After it fades from view, you watch the video you recorded, which shows the entire event exactly as you remember it.
After such an experience, you would likely be convinced that something extraordinary was indeed happening in your friend's house. You might show your video to others or post it online, hoping to discover other possible explanations. You might return the next night, with more friends and more recording equipment, to validate your experience. You might try interacting with the ghost, to see if it responds or not. You'd watch carefully to see if its appearance and movements are always the same each night. You could show your evidence to neutral third parties, convince them to conduct their own investigations.
Eventually, if all observations both human and technological continue to verify that the ghost really does appear in the same spot every night at midnight and can't be easily explained away as an optical illusion, clever prank, or mass delusion, everyone would be forced to conclude that there really is a ghost, or at least there's something going on, and in a preliminary way it's consistent with our popular mythology about ghosts. Studies would have to be done to try to understand what it is, what it's made of, where it comes from and goes to. There would be lots of interesting questions to answer. Like, does the ghost honor daylight savings time and move its appearances by an hour when the time changes?
A whole scientific field of ghostology might emerge from this discovery; perhaps the knowledge gained would shed light on other, more marginal cases, opening a new frontier in the quest for knowledge. Perhaps whole new laws of physics would be discovered, leading to unforeseeable advances in technology. Perhaps it would confirm some form of life after death, causing religious revolutions or reformations. It would, no matter what, change the world. Whatever its precise nature turned out to be, a reasonable skeptic would have to agree that yes, the ghost exists.
Scenario Two: As you're sitting with your friend in their darkened house, the stroke of midnight arrives, but no ghost appears. Your friend appears perplexed and confused, but after some time they are forced to admit that the frightening incident they witnessed alone has not repeated itself. Perhaps they still believe in the ghost, and think that your presence kept it from appearing somehow. Or perhaps they admit that they may have been mistaken, or dreaming, or hallucinating.
Although you can't say whether or not they actually saw something, the fact that your close friend had such a vivid and disturbing experience is still concerning. You might probe a little deeper, find out if perhaps they are under a great deal of stress, suffering from a sleep disorder, or showing any worrying signs that might indicate mental illness. Depending on what they say, you might simply keep them company and reassure them it wasn't real, or you might decide to advise them to seek help from a qualified mental health professional.
Whatever explanation your friend decides on for themselves, it's clear to you that you are not going to see any ghost. In that case, can the ghost be said to exist, in any meaningful way? If so, it exists only in your friend's mind. Does the ghost exist if it only exists for one person?
There are many things that are only experienced in our minds, and not easily verified by others: personal beliefs, feelings, ideas. Things that only we experience must exist, because they have immense influence over how we behave. If no one but your friend ever sees the ghost, but seeing the ghost profoundly changes how they think and act, then the ghost was real as far as they're concerned.
Scenario Three: As in the second case, no ghost appears at midnight. Your friend is relieved and admits that perhaps it was all just in their imagination after all. Comforted by your companionable presence and the ridiculousness of the whole situation, your friend's worries are put to rest. Satisfied that there is no ghost and that your friend is okay, you and they pass the rest of the night laughing about the whole thing and telling each other ghost stories. You speculate about what might have happened if there really had been a ghost, and concoct a fictional adventure around the encounter.
At some point in the evening, you give the fictional ghost a name and biography (necrography?). You call her Maybel, decide how she died and became a spirit, and what the two of you would have done when she appeared. You both end up enjoying the story so much that you decide to tell it to others. Maybe you both believe the ghost really exists, or maybe not. Other people you tell may believe the stories, or not, and might pass them on either way.
Whatever specifically happens, the ghost might now be said to exist, at least in the minds of those who hear and retell the stories about it. Many fictional characters exist this way; it'd be silly to say that Jean Valjean or Buffy Summers "don't exist" just because they were never actual living humans. Fictional characters have immense impact on the world through the ways they inspire and influence us.
The Three Worlds ontology offers an explanation for the different ways in which these three different versions of the ghost "exist": three distinct but related kinds of existence, which don't contradict or invalidate one another. Popper called them World 1, World 2, and World 3.
World 1 is the physical world that exists outside of our conscious experience. It is the world of atoms and molecules, planets and galaxies, laws of physics and fundamental forces. It is the world that exists whether anyone knows it or not, the world that we can only discover via our senses and experimentation. Although it is... well, everything, it is also possibly the most difficult world to understand because our access to it is so limited by the particular properties of our physical forms.
World 2 is the personal, mental world of an individual. It is our dreams, imagination, thoughts, and feelings - our entire conscious and unconscious experience. Your psyche is entirely unique to you, and also completely inaccessible to any other person. This idiosyncratic inner life is completely real to you - just as everyone else's is to them.
World 3 is the interpersonal world of thoughts and ideas that are shared by multiple people. This is the world of art and literature, languages, engineering, theories of theology and science, the value of money, borders between nations... in short, anything that exists because we agree that it does.
In his 2011 book Sapiens, historian Yuval Noah Harari called the Three Worlds the Objective, Subjective, and Inter-subjective, respecitively, and posited that the ability to develop shared fictions - the inter-subjective - is the key differentiator between humans and other animals. In one of his most evocative examples, he invites the reader to imagine the consequences of filling a sports stadium with chimpanzees rather than humans. It's an excellent book and well worth being familiar with, and his terms for the three worlds are less awkward to drop into a sentence; I use them interchangeably.
I mentioned earlier that these three types of existence don't contradict or invalidate each other. What I mean by that is simply that these are not completely indpendent realms; they form a hierarchy of existences such that objects in World 3 must also exist in World 2, and objects in World 2 must also exist in World 1. In philosophical parlance each world supervenes on the one below it; an object in one world depends on its existence in the ones beneath it.
For example, the poem The Road Not Taken by Robert Frost exists Inter-subjectively, as a work of art known by many people. It therefore also exists Subjectively in the minds and thoughts of every person who has read it. In order for it to exist in someone's mind, it must also exist Objectively as an arrangement of neurochemical states in their brain.
This isn't true the other way around: objects in World 1 do not have to exist in World 2 - a great many physical objects exist that no one knows about. Objects in World 2 don't have to exist in World 3 - any thought or feeling you've never shared with someone else has no presence in World 3.
Popper proposed, therefore, that something can be said to exist if it has a "causal effect" on physical things. My hunger exists, if it compels me to get out of my chair and make a sandwich; my pain exists if it causes me to move away from it. Stephen Hawking used a similar turn of phrase - "observational consequences" - that he used when discussing cosmological questions like what existed before the Big Bang or what happens to something that falls into a black hole. Those then become examples of things that don't exist, because they can no longer have any affect on the physical world.
If Subjective objects exist because they can affect the physical world, it follows that Inter-subjective objects exist if they can affect our Subjective worlds. Fahrenheit 451 will exist for as long as people read it, discuss it, and are influenced by it; Les Miserables exists if it continues to inspire us to be better people. World 3 objects cease to exist when no one remembers or cares about them anymore; for example lost works of art, and lost languages. Edge cases, like languages where we have samples of their writing but don't know how to translate them, are intersting to ponder. If we someday discover a Rosetta stone that allows us to translate writings in Linear A does that ancient Minoan language suddenly pop back into existence? Where did it go in the meantime?
Having a comprehensive ontology is critical to building a complete philosophical worldview. Without it, we cannot answer questions like those posed about the ghost at the beginning of this post - does it exist? What does it mean for it to exist or not? What kind of existence does it have? I find that Popper's Three Worlds provides the most complete ontological framework for answering these questions. In future posts in the Ontology series, I'll attempt to answer obvious concerns about the Three Worlds ontology and give more concrete examples of how it can be applied in the real world, and expanding on the concept where necessary.