"Washington, D. C., is the home of The Bureau of Standards. Every weight and every measure that is used in the United States is a copy of the standard that is kept inviolate by the Bureau in Washington. In that Bureau there is a perfect inch, a perfect foot, a perfect yard, a perfect gallon, a perfect pint, a perfect millimeter, a perfect milligram. Every weight and measure that we have finds its standard in that Bureau in Washington, and all are judged by that standard."

Let's say that in the Bureau of Standards in Washington, D.C., there is a platinum rod that defines the length of the yard. How do we know that that platinum rod is really one yard long? Should we all get out our wooden yardsticks and measure it just to make sure? No, that would be senseless. Doing that would test not the rod but our yardsticks because that platinum rod defines exactly how long a yard is. That rod is the standard by which we measure all our yardsticks, and no yardstick can sit in judgment over it.

The evidentialist is like a person who insists that his wooden yardstick proves that the platinum rod is one yard long. He treats his wooden yardstick as if it were the national standard and the definitive measure.

The fideist is like the person who burns all his wooden yardsticks. He says that the platinum rod is all he needs. Who needs a wooden yardstick?

The presuppositionalist agrees with the fideist that the platinum rod, not a wooden yardstick, is the final and definitive measure of the yard. Yet the presuppositionalist agrees with the evidentialist that wooden yardsticks are important and have their use. After all, the wooden yardsticks are modeled after the platinum rod, and that is why they are reliable measures. Our experience of their reliability in measurement confirms our faith in the platinum rod. That's because the platinum rod was the standard by which all the wooden yardsticks were manufactured.

The presuppositionalist is the one who believes both in the final authority of the platinum rod and in the use of wooden yardsticks. Presuppositionalism incorporates the strengths of both fideism and evidentialism while avoiding their weaknesses.