Yes, entropy can only be measured in relation to an expected probability distribution. You need to have an a priori model for how the password is generated (sel

Yes, entropy can only be measured in relation to an expected probability distribution. You need to have an a priori model for how the password is generated (selected) to estimate its entropy. So the dichotomy you set up is IMO a false one, in that you are guessing about how the password was generated.