The prevailing view among historians is that medieval European peasants were deeply dedicated to religion.
Conclusion
There is reason to doubt the prevailing view of peasants' piety. (i.e., not so sure that medieval peasants were deeply dedicated to religion)
Evidence
The record keepers of medieval Europe were clergymen. And it would be in their professional interest to embellish how religiously devoted people were.
Evaluate
Given That our source of records of medieval times are clergy members who are biased in favor of exaggerating people's religious devotion,
How Can We Argue That this is no reason to doubt the religious devotion of the medieval peasants (i.e., that the peasants really were religiously devoted)?
Goal
We either want an answer making us less skeptical of the accuracy of the clergy's record keeping (it would have been a sin for them to embellish the truth) or an answer that just independently helps us believe that peasants really were religiously devoted.