A solipsist is someone who believes that only they exist - that they are imagining everything they experience, and nothing is real other than their own minds. It’s quite possible you know someone who believes they invented you, Einstein’s theory of relativity, the poetry of Emily Dickinson, World War II and the color yellow.
There are different degrees of solipsism ranging from the belief that technically, we only ever experience our own thoughts about reality and not “actual reality,” if there is such a thing, to the firm belief that absolutely nothing exists at all, everything is an illusion except for the mind of the person in question. The latter point of view is called “metaphysical solipsism” because it makes a claim about the nature of reality.
An illustration of this idea can be found in "The Mysterious Stranger," a little-known novella published by a late-in-life Mark Twain who had lost his wife, one of his daughters and much of his faith in humanity. It tells the story of an Austrian boy visited by Satan, whom at the end of the tale tells him:
“Nothing exists; all is a dream. God--man--the world--the sun, the moon, the wilderness of stars--a dream, all a dream; they have no existence. Nothing exists save empty space--and you!...Strange! that you should not have suspected years ago—centuries, ages, eons, ago!—for you have existed, companionless, through all the eternities…there is no God, no universe, no human race, no earthly life, no heaven, no hell. It is all a dream—a grotesque and foolish dream. Nothing exists but you. And you are but a thought—a vagrant thought, a useless thought, a homeless thought, wandering forlorn among the empty eternities!”
A person I know on the solipsism spectrum described this as one of the most beautiful passages they’d ever read.
Solipsism is probably more common than one might imagine. During a break this past semester, I was having a conversation with a classmate. When I mentioned solipsism, they remarked, very causally and seriously, that they were believing in it more and more every day. Earlier, they had told me that they thought I might be a reptilian. Why this person was talking to me if they thought I was a hallucinatory cannibal alien is as much your guess as mine.
Usually when the words “solipsism,” or “solipsistic” are used, it isn't to describe a belief, it’s to criticize behaviors or attitudes that are myopically self-absorbed. We all, from time to time, have moments where we act as though other people have no existence other than as furniture in our private worlds or as supporting characters in our own hero-narratives. You probably understand this attitude especially well if you’ve been on the receiving end of it, say, in an abusive relationship or working in customer service. However, even people who think and act like this nearly all of the time - the kind of people we classify as pathological narcissists and sociopaths - would probably, if asked, agree that other people, and the world, do in fact exist. Most terrible people accept, at least intellectually, that the other humans they interact with have their own being and agency independent of their observations and interactions, even if this belief does not really factor into their everyday decision making. Metaphysical solipsists go beyond this; they elevate narcissism to a religious belief.
Solipsism is somewhat similar to certain strains of Eastern thought and belief, where all is thought, and everything perceived by the senses is illusory and “empty,” at least in relation to some inexpressible ultimate reality. However, in these systems, the goal is often to lose one’s sense of self, to achieve a state in which one loses one’s ego and realizes the fundamental oneness of all things. Metaphysical solipsism inverts this experience; it inflates the ego to the size of the cosmos.
Solipsism recalls the philosopher Descartes' famous slogan, "I think, therefore, I am." He noted that although one could theoretically doubt nearly everything, including the actual being of the world one appeared to see, touch, taste and smell, it was nonsensical to doubt one's own existence because someone had to exist to be doubting. Descartes did not actually claim "I think, therefore I am" was the only thing someone could believe, though - he thought of it as the first step in considering what one could have certainty in, a path which, for him, ended in God. When considering whether or not we should believe something, we should consider several questions - is the belief provable? If it is not provable, but not disprovable either, is it reasonable? Is it helpful?
It’s perhaps worth noting that solipsism, when voiced by someone else, is one of the only beliefs ever in history which is objectively not true. Solipsism is not provable or disprovable. It's also, I’d argue, not reasonable, what reason does one have to doubt one’s senses? If everything you perceive is an illusion, there is no difference, in your experience, between an illusion world and a world where everything does exist independently of you. Considering the second world has other minds that could manipulate you, and plot your death or downfall if they wanted, it's in your interests to believe in and prepare for that one. It's also more exciting.
One argument against solipsism is that one would expect that, if one was imagining everything, but unaware of this fact, once one did become aware one could become a reality-warping god. Solipsists, going by the solipsism Wikipedia page, counter this argument by proposing that they do not have power over the illusions of the world because they are produced by an unconscious or super-conscious “locked” part of the mind. The problem with this is that here solipsism loses its supposed hardcore standards of what can be proved. Once you have to invent mysterious magical mechanisms for how solipsism works, it's clear you aren’t being any more logical than anyone else making any kind of claim about what created the universe. Claiming that reality is created by a locked part of your mind which you do not experience directly is not much more logical than claiming, as theists do, that it is created by a mind above you (God), or by a genie, or me. It’s possible everything is just in your head; it’s also possible that you are a robot I built, implanted with false memories, and switched on mere seconds ago, and that I am amusing myself by programming you to read this.
If you are a metaphysical solipsist and have convincing arguments for me/you that you are the only thing in existence, feel free to post them in the comments. However, I won’t feel obligated to consider them, for they might just be figments of my imagination.
