We assume we will wake up in the same bed we fell asleep in, the kitchen will still be down the hall, our clothes will still be in the closet, safe drinking water will still come out of the faucet, our workplace will still be in the same location as yesterday at 5 p.m., and air will still contain adequate oxygen. Virtually everything we do is based on acceptable, but not valid, premises. An earthquake or tornado could change everything we assumed would be true. Only 99.99999 percent of people have been mortal, so this is not strictly a valid argument. This is where faith comes into play.
Scientists exercise faith in their instruments and their own powers of observation.
There is always the very slight chance that their readings and observations are inaccurate. As long as any premise is less than 100 percent, faith is required to act upon it. But once we claim Christian doctrines are valid, unbelievers can tear our reasoning apart by reducto ad absurdum. This strategy disproves an argument by showing that at just one point, at just one time, it is contradictory or inconsistent. This distinction between valid and acceptable arguments, however, can work to the Christian's advantage.