... all knowledge - all knowledge - involves a personal decision to commit oneself to an epistemological framework in the absence of compelling a priori evidence to make the decision. There is no Cartesian point of objectivity from which one may serenely decide between frameworks.
Here's a slightly-edited version of my response.
It seems to me that Todd is saying each of us must choose his or her epistemological framework. That strikes me as saying we must each choose our own truth. I don't think either claim is defensible.
I would argue that, so far as we can tell, there's a single reality, wrought by the Creator (though sometimes different people perceive that reality in different slices, or from different perspectives).
Likewise, there's a single epistemology, a single approach to assessing what we know and how we know it: As best we can, face the facts of reality as they’re revealed to us — keeping in mind that those facts include the limitations of our abilities to perceive, correlate, remember, and communicate.
As near as I can tell, the post-modernist view maintains that our limitations require that we abandon the notion of objective reality. That doesn’t seem correct.
Our knowledge of reality isn’t a painting that each of us must examine in the moment, alone and in a vacuum, with no information about the depicted scene except as supplied by our imaginations.
Thanks to our gifts of "memory, reason, and skill" (Eucharistic Prayer C, if memory serves) — especially the skill of communicating with each other — our knowledge base is more like a movie: Our past experience, individual and collective, allows us to know more about the scene than could ever be depicted by a painter.
Consider that over millennia, humanity has accumulated gazillions of observations of the Creation.
Individually, each observation is subject to error in perception, recordation, transmission, and/or interpretation.
Collectively, though, our accumulated observations — including meta-observations about how we make and use observations — can give us something like a serviceable facsimile, within its limitations, of the Cartesian point of objectivity Todd describes.
In The Wisdom of Crowds, James Surowiecki tells of a surprising observation by statistician Francis Galton; as explained by an Amazon.com reviewer:
In 1906, Francis Galton, known for his work on statistics and heredity, came across a weight-judging contest at the West of England Fat Stock and Poultry Exhibition. This encounter was to challenge the foundations of his life's study.
An ox was on display and for six-pence fair-goers could buy a stamped and numbered ticket, fill in their names and their guesses of the animal's weight after it had been slaughtered and dressed. The best guess received a prize.
Eight hundred people tried their luck. They were diverse. Many had no knowledge of livestock; others were butchers and farmers.
In Galton's mind this was a perfect analogy for democracy. He wanted to prove the average voter was capable of very little.
Yet to his surprise, when he averaged the guesses, the total [sic] came to 1197 pounds. After the ox had been slaughtered, it weighted 1198.
Emphasis and extra paragraphing added.)
Surowiecki gives several other examples — including how the sunken submarine USS SCORPION was located — to illustrate the point: If each of a (sufficiently-large) number of 'observations' includes a randomly-distributed error component, and the observations are mashed together, e.g., by averaging them, then the error components tend to cancel each other out, and the resulting collective picture can be a serviceable representation of the underlying reality.
I'm now bumping up against the limits of my (scant) knowledge of epistemology. It seems to me, though, that Galton's story of guessing the weight of an ox is a useful metaphor for how our collective experience over time helps us compensate for the lack of an a priori frame of reference.
(If I'm not mistaken, what I've described above is a crude summary of the notion of critical realism.)