Antonin Scalia himself has made this notion of pure interpretation an acceptable standard by which to criticize court appointments through some treacherous claims about his ability to channel the minds of our dead founding fathers.  His "originalist" stance on constitutional interpretation has become a bludgeon against any possibility of a left-leaning Supreme Court nominee.  But he would take issue with my interpretation: he would say he's not trying to read minds but to read what the words meant to Americans in the late 18th century.  Here he is defending that point in his 60 Minutes interview: 

"...it isn't the mindset. It's what did the words mean to the people who ratified the Bill of Rights or who ratified the Constitution,"

How he could know what the words meant to these people any more precisely or purely than anyone else who reads history is left for us to guess.  

Now, I know you might be thinking that we have a way to get at the meaning of these words without mind reading or time machines, and you will hear no argument from me on this.  One need not be a historian or academician to get at the meaning of words from other time periods.  The point here is that there can be no pure interpretation.  No matter how we try, we are unable to differentiate ourselves from our interpretive functions and get to a "pure meaning".  

In other words, the distinction Scalia and others appear to make is not a real one.  Immanuel Kant set the tone of all of modern philosophy in defining (or observing) a model for how our perception processes are fused to the perception itself... and we have failed repeatedly for over 200 years to think our way out of this model.  The bottom line is this: interpretation is an active process.  Nothing that is understood is pure.  It's like the Uncertainty Principle for cognition.  Seeing a thing changes it's trajectory--if only slightly.  But we cannot be certain of how much it's changed because that requires another observation... and so on.

And this is not just academic hair-splitting.  Scalia and all the talking heads on cable news that believe he is making a real distinction need to be called out--somehow walked through how they think one person can interpret "purely" and another is biased.

This is not to say bias is not real.  It most certainly is.  But that is the only real discussion to have: what degree and kind of bias is being injected into a particular decision?  

Outside of that, the discussion only illuminates political bias or just a lack of understanding.