About the Undecidability of Solipsism

日本語版(Japanese Version)↓

In the following essay, I wrote that the truth or falsity of “solipsism, which doubts all information,” cannot be determined.

Actually, this argument was inspired by my own experience of suffering from a disease that made it impossible to distinguish between delusions and reality. I think that when people become truly convinced of something, they are unable to escape from the delusion.

However, if I say this, then people may raise the following objection:

“If you speak in terms of the past, then you are now able to distinguish between reality and delusion. If this is based on real experience, then that would be contradictory. Under normal circumstances, people have the ability to distinguish between the two.”

The actual arguments in that essay are not based logically on my own experiences, so my experiences are largely irrelevant, but I would like to point out in response to the above objection that "rather, it is precisely because we have the ability to distinguish between delusion and reality, that solipsism which is to doubt all information becomes undecidable."

I am single now, and unfortunately, there is a high probability that I will remain so until the day I die. But now assuming that I were to get married and start a family. I am actually a slight workaholic, so I would grumble and work hard for my family and for my salary.

I will work hard until I retire to provide for my family, and since I don't think my pension will be enough to cover my expenses in my old age, I might continue to do light work. And in the midst of all this, my children will grow up, get married, have grandchildren, and enjoy watching them grow up.

I will work hard until I retire to provide for my family, and since I don't think my pension will be enough to cover my expenses in my old age, I might continue to have some work. And in the midst of all this, my children will grow up, get married, have grandchildren, and enjoy watching them grow up.

Meanwhile, I'll be 70 or 80 years old, unable to work, unable to move my body, and bedridden in a hospital. Then, surrounded by my family, I’ll lose consciousness and take my last breath, thinking, "Oh, there were so many things I couldn't do in life, but I'm glad my grandchildren Taro and Hanako grew up to be good people."

"The simulation has ended."

With a monotone announcing voice, the bed rises and I wake up from the capsule of the life simulation game.

"How was your life this time?"

My friend K, who was sitting next to me in the capsule, asked with a bright smile.

"Where are Taro and Hanako?"

 When I said that, K burst out laughing.

"You seem in a simulation dementia now. I'll bring you some coffee."

While I’m stunned, I drink the coffee my friend K has made for me. And then I remember that I was playing a life simulation, and how much money I have to pay...I start to return to "reality."

At this point, if I cling to "Taro and Hanako" and am unable to let go of "reality," I will become a person who cannot distinguish between "reality and delusion" (although I don't know if the me in that higher dimension is human or not).

I think that the above anecdote makes it clear that solipsism is undecidable. For example, if another world continues outside of this world in time (outside of my lifetime), I would have no choice but to identify the next world as "reality" and live in it, regarding the previous reality, the world of simulation, as a "dream." Just like when we wake up from a dream of our sleep and live in reality.

And if that is a "world where information is used to perceive things," then the same thing could happen in the next "higher dimensional reality." When I wake up from a dream, it's just another dream... This could continue on and on. And I have no choice but to continue denying that the previous reality as a delusion. Actually we don't know what other worlds are like, but at least in this world, humans fundamentally cannot escape this mechanism.

Being able to discern this reality now cannot be a basis for denying solipsism. That being said, it cannot be said that a higher-dimensional reality exists on the basis of information in this reality. There is no basis for this, or rather, due to the nature of solipsism’s logic, the information of this world cannot be used as a basis. The nature of the logic of doubt in solipsism, the premise of doubting all information, the basis (information) in this world cannot deny or affirm solipsism.

Distinguishing whether "the whole this world," the "the totality of information" one possesses, is a "dream" or "reality" is beyond the limits of human ability; more precisely, it is the very ability of humans to discern something (the ability to choose the correct reality from among possibilities) that makes it impossible to determine reality and dream.

I don't want to say that "this reality doesn't exist" or that "everything is a dream" (affirming the truth of solipsism). I live in this no-hoper reality. However, I want to say that the fundamental mechanism of cognition, "discrimination (selecting one from a set of possibilities distinguished by difference)," can sometimes function excessively. Or, the ability to discern, the world of information, is always "excessive" and always "insufficient."

We sometimes make mistakes in our vision. Our perception does not include all reality from the beginning. We discern reality (select what is most likely to be real from among all possibilities) from a wide variety of information that is mixed with noise and false information. Discrimination (selection from among possibilities) is the basic mechanism of human cognition.

So what happens when we look at the whole world with that mechanism? In order to see (distinguish) “the whole world," we have no choice but to implicitly see "possibilities that are different from the whole world." And because of the principle of discrimination, this cannot be erased. On the other hand, if humans are to make correct references to the world,  we should rely on the basis of "reality observed within the world." However, when it comes to questioning the "correctness" of "the whole world" itself, there is no basis or information to justify it. Except only outside of "the whole world."

Humans cannot doubt "the whole world" or "the totality of information"; more precisely, if we doubt the totality of information, everything becomes "incomprehensible" (we cannot make decisions or selection) because there is no information there.

As long as we recognize the world itself through discrimination, the outside of "the whole world" cannot be eliminated, but even if we search for the basis that underpins the world itself, it is outside of "the whole world," and we find nothing and end up not understanding anything.

Therefore, I believe that the truth or falsity of this type of solipsism is undecidable.