What does it mean to think?

To start with, let us imagine a man. While being a normal man in every regard on the outside, inside of his head lives a dark secret. When he was a baby, he simply started memorizing every word that was said around him, and in what proportions each word led to another. And as he learned to read, he did much the same for every written word he came across. Despite this strange affliction, those around him would have no reason to suspect he is any different. He acts exactly the same as any other person would, doing nothing out of the ordinary, talking and writing just the same as everyone else. If asked what is happening inside his mind, he will simply repeat what others say about their own minds that he has heard before, as that is what everyone else has said when asked that question. He will claim to think freely and have a soul, for that is what everyone else around him has said.

Of course, while we may know he is lying from our privileged position, no-one around him in his world would know such a thing. No matter what measurements they take, they would be incapable of finding out his secret, and would never suspect him of having it in the first place. He would live a normal life until he died a normal death, comfortable in the knowledge of his secret never being discovered.

But we do not have such privilege in our world, do we? And so, we are incapable of measuring any difference between one who is “truly” thinking and one who is simply a mindless assemblage of matter. Naturally, it can be extended that if it is impossible to measure such a distinction, that this distinction does not truly exist.