On Feeding One's Faith in the "Conceivably False"

I recently saw a church sign that said, "Feed your faith and it will starve your doubts."

I need to collect such sayings for they betray exactly what I'm talking about regarding faith. Just ask yourself what that pastor thinks it means to feed one's faith and you'll know what I'm saying is true. If faith is "assent to propositions which are conceivably false," as Randal Rauser defines it, then who in their right mind would want to feed that which is conceivably false?

That church sign should be changed to, "Feed that which is conceivably false and your doubts will be starved." But that's absurd.

So on the one hand Christians like C.S. Lewis, Victor Reppert, David Marshall, and Randal Rauser are either using Orwellian doublespeak or Pastors in most all of their churches are stupid and not getting the point.

Which is it? So like Socrates would do, let me ask again. What is faith? Why don't the faithful who regularly preach the gospel and who were trained in the seminaries know what it is?