I haven't seen the discussion that I think is really necessary - when are we going to move beyond passwords, which are obviously growing more and more obsolete? What are we going to use instead of passwords in the future?
And of the 3 What you know (i.e. password) is the most secure when used properly. It's impossible to steal without your knowledge, and it's impossible to misplace.
What you have (eg. physical key) can be stolen from you - or even borrowed, used, and returned without you ever knowing. It can also be copied, and it can be lost - sometimes without being aware of it for a long time.
What you are (eg. fingerprint, iris) is the worst, and the least secure. It's trivial to copy - even from a distance, and it's impossible to change. The entropy available is also low.
So in the future we are still going to use passwords.
