Consider the proposition: He makes sure what it means to him by …. Would you say the word had meaning to him if it ‘meant something else’ even time? And what is the criterion of the same colour coming twice. showing now what is knowing what seeing is .
     In knowing what seeing red is you seem to give yourself a sample but you don't because the usual criteria for the sameness of the sample don't apply. I can say I call ‘red’ always the same colour or whenever I explain red I point to a sample of the same colour.