Wittgenstein’s a bit of a difficult one. In a funny way what he is saying is so simple, so in your face that you can’t quite grasp it. My grand-dad had an aphorism about maths that seems to fit Wittgenstein: “Maths is so easy it’s hard”.
I’ll give a quote and riff from there.
“504. But if you say: “How am I to know what he means, when I see nothing but the signs he gives?” then I say: “How is he to know what he means, when he has nothing but the signs either?” Philosophical investigations.
Say I have an image in my head and I try to communicate it to you what do I do? I may describe green trees and such and this description would be vague but it would be the way I would talk to myself about the image.
I could even go into minute detail by giving an exact mathematical description of the image. Like a computer graphic and the binary code that produces it.
I could even draw the image for you.
The thing is that the very means I use to see this image in my head are those that I can use to give you the image. There isn’t something hidden behind the image or the words just various degrees of exactness in the description.
There’s the old problem of how do I know that you mean what I mean when you say what I say. For example when you say you are in pain are you experiencing the same thing as me?
I think Wittgenstein would agree that you cannot be certain in the philosophical sense but he would then shrug his shoulders and say so what.
When you experience pain you act in a certain way. When you were young and being taught language when you behaved in this way you were given a particular training and treated in a particular way.
People would have said things like “Ahh does it hurt” and given you some paracetamol.
It could be that you exhibited this behaviour in response to a different sensation to the sensation I have when I behave this way.
We can also imagine that the treatment has the same effect – it stops you behaving in that way – as it does with me. If all this was the case then it doesn’t matter whether or not you experience the same thing as I do when you act out pain.
“If there is a bit of a machine that has no effect upon any other bit then it isn’t part of the machine” (It’s not verbatim but it is another quote from Wittgenstein.