My second example comes from 1Tim 4:
- 1Now the Spirit expressly says that in later times some will depart from the faith by devoting themselves to deceitful spirits and teachings of demons, 2through the insincerity of liars whose consciences are seared, 3who forbid marriage and require abstinence from foods that God created to be received with thanksgiving by those who believe and know the truth. 4For everything created by God is good, and nothing is to be rejected if it is received with thanksgiving, 5for it is made holy by the word of God and prayer.
6If you put these things before the brothers, you will be a good servant of Christ Jesus, being trained in the words of the faith and of the good doctrine that you have followed. 7Have nothing to do with irreverent, silly myths (muthos). Rather train yourself for godliness; 8for while bodily training is of some value, godliness is of value in every way, as it holds promise for the present life and also for the life to come. 9The saying is trustworthy and deserving of full acceptance. 10For to this end we toil and strive, because we have our hope set on the living God, who is the Savior of all people, especially of those who believe.
That's why context is so important in looking at a question like this. In leading up to his admonition to young Timothy, Paul clearly spells out that one will depart from the faith if one accepts the teaching of "liars" and "demons". It cannot be any more plain on Paul's part that there are some who teaching something which is in a category in opposition to the teaching of the Gospel. That is to say, it is possible to believe something false which would nullify the claim of "faith" because its content would be at odds with true faith.
We're going to pick up some steam as we observe the other uses of the word "muthos" in Paul, but let's not allow the velocity of the exposition to undercut the importance of the point: affirming the view that pre-enlightenment readers and writers did not uphold epistemological categories in their thinking or in their methodology is simply unsupportable in fact when it comes to the NT documents.