"""
why waste time on something you "don't know" will work
For the same reason that I'm willing to fly to any large airport without knowing for sure that there will be a taxi waiting. There almost always is.
"""
This is something that you've 'learnt' based on prior experiences. And based on past experience you know that the probability of a taxi waiting outside an airport is high. So, its not completely 'unknown'.
""" why waste time on something you "don't know" will work
For the same reason that I'm willing to fly to any large airport without knowing for sure that there will be a taxi waiting. There almost always is. """
This is something that you've 'learnt' based on prior experiences. And based on past experience you know that the probability of a taxi waiting outside an airport is high. So, its not completely 'unknown'.