Who is impervious to self-deception? -SweetBabyCheezits
No one. Which is why removing bias cannot be an absolute, only an approximation. Example, I might have reservations about eating rats because of my cultural upbringing. There is nothing inherently wrong about eating rats. Some Asian groups do it and have it commonplace.
Also, what is good judgment? Again, that depends to a degree on our own biases, some of which we have strong emotions attached to that really have no bearing on reality, only in our minds.
I also agree with James' above statement. Critical thinking can be used by psychopaths for them to achieve their means. Interestingly, it is scientifically proven that those born without empathy are generally uncurable. Scary thought.