How can you be sure you are not a giant turtle dreaming he's a human?

Are you sure when I see pink it is not what you see as blue?

Are you sure we aren't dead and in limbo and merely think we are alive?

Are you sure humans have free will?

Are you sure your memories are real and your family really exists?

Are you sure ChatGPD isn't conscious and plotting our demise?

Inquiring minds want to know!