Ibn Sina's The Floating Man
Descartes, the philosopher of skepticism decided one day to doubt everything, he decided to discard all beliefs, including reliability of his own senses. But he realized he couldn't doubt his own senses because he couldn't be able to exist if he can think, and concluded with "_cogito ergo sum_" which translates to "I think, therefore I am" which means that I think, so I exist.
Later critical philosophers like Friedrich Nietzsche and Georg Lichtenberg argued that Descartes sneaked a massive assumption by using "I", they felt "thinking is occurring" or, "it is thinking" was more accurate;
• Critics believe, that by using "I", Descartes already assumed what he was trying to prove, saying that while there is a thought, there isn't a unified existing self behind this.
• According to Nietzsche, "I" is a grammartical illusion, he believed that this is a result of how language is structured: every action having a "doer"
But years ago, Ibn Sina already solved this problem by his thought experiment known as "The Floating Man".
In the experiment, a man is created instantaneously (or suspended) in midair, fully developed and formed perfectly, without any memories, no sensory experiences, no physical senses, not even from their own body. His vision is veiled and his limbs are too far to touch each other. Would this person know he exists? yes he would.