Septic or Sceptic?

Septic or Sceptic?
If you cut your finger and it later goes black, throbs and fills with oozing pus, you could say your finger had gone SEPTIC and you would mean germs had got into the cut and started their dirty work.
On the other hand, if you went around saying that we don't know for sure what is true and what isn't, and will never be able to find out for certain, then you could call yourself a SCEPTIC.
One of the first sceptics was a fantastic philosopher called Protagoras, who lived around 450 BC.
He is famous for saying:
MAN IS THE MEASURE OF ALL THINGS.
He meant that people decide for themselves what they want to think of as right or wrong, true or false.
Do you agree with Protagoras?
Or do you think that there would be a right or wrong, true or false even if humans didn't exist?
People like Protagoras, who think you can never know the real truth about anything, are still called sceptics. And if someone is sceptical of what you are saying, it means they aren't sure that you are telling the truth!