Imagine living in a world where you're the only human and there are no reflective surfaces.
How would you know you had a head? You would see through your eyes, breath and eat with your mouth, touch your hair and face, etc. But you would have no "proof" your head existed because while you had constant direct experience of your head performing its functions, you would have no 3rd party objective confirmation that you had a head at all.
How does the knower know itself outside of its experience?
@Tfmonkey You wouldn't know for sure. Your senses aren't utterly reliable to perceive what is true.In that case your only certitude is that something thinks. You know you think because you wouldn't possibly interrogate yourself over trying to know if your head is still here or not.
And if you think, there must be something doing the thinking. Let's call it the 'I'.
I thinks, so you know I exists.
I think, therefore I am.
And I am not certain I have a head.
But someone should give me one...
