Solism

The legitimacy of solism as a philosophy.

I read once about the theory of solism, or egism. The passage was brief and I found the analysis of the theory delightfully ironic. To paraphrase, it read, "however, there are schools of thought or major writings on the topic."
If you are the only sentient, real creature in the universe, who do you need to tell the theory to? So no one else "matters," in the philosophical sense, and when you die, the universe ceases to be.

Everyone is the center of their own universe. You are the center of your universe. It began at your birth and will end at your death, simply because there is no other way to disprove this. Any objections to this are speculative, and, since they can never be proven, unless you inhabit the mind of someone else, are irrelevant. Whether you are "god" or there is another, be it an equal or a superior being, is also irrelevant.
As such, ignore any pretense that anyone or anything else but you has, does or will exist.
The rules for behavior are simple: you have elected to inhibit a human body with a limited lifespan obeying other rules of physics, the passage of time, and whatever society you have chosen to inhabit. You have created others with whom interact who also obey the same set of finite rules. You have created a fictional history of the universe before your existence that all of these characters and yourself choose to believe, because there is nothing else to believe. Since you, in this body, can not travel through time, can not disprove this fiction, it is true in the sense that it is uniformly believed.
However, everyone else, whether they exist as sentient beings, characters in a story or mere figments of imagination is also irrelevant. Everyone believes they are the center of the universe. Understanding this cognitive rationality is paramount to interaction with them, whatever they may be.
The reason society functions at all given this fact is that members of it choose to play the game that others exist, whether or not they do. They also obey the rules of corporeal existence in a limited space-time continuum.
We chose to play this game because we cannot break the rules we ourselves have created and the only other option is self-annihilation.

Whether the reality of what we have been told the nature of the universe is is true, or whether this theory is true, the point is that we must obey the rules we have established until we end. When we end, either the universe ceases to be along with us and the hiccup in time and space ends as well, or we find out that the game is over and go back or forward to whatever state of existence truly is. If we are god playing a game, we go back to being god. If we are mortal and there is a god, I'm sure we speak at length over the experience. Granted, if there is no god, but a corporeal universe, then we still cease to be, but the universe continues on as it has for eons.

Metaphorically, imagine that you are seated at a table on a platform floating in space. Before you, sits a massive chess board or Monopoly game, deck of cards, whatever, and you play an invisible, incorporeal opponent. If you win, you play again. If you lose or refuse to make any moves for too long, the platform and table disappear and you fall. You have no choice but to play, make a running leap off the edge or refuse to play. Even if you win, you will eventually lose. With nothing else to do until then, why not play? Find joy in the game.

Conversely, imagine that you are an author thousands of years from now. You have written a fictional novel of a character with your personal history. However, rather than read it, you live it. The book does not end, and you do not leave the novel and return to your author life until you die in the book. The author creature you are may make nothing like a human, may be a jelly, a being of electrical energy, or may have the ability to travel through time, or may be god with an itchy pencil. Either way, the author has chosen to write about a human life. You are that story.