The Continuum Between Knowledge and Ignorance

§3.2

To get a sense of the continuum between knowing something and being wholly ignorant of it, it helps to consider some examples. Let’s start with the following scenario: While walking across the quad one day at 8:00am, you see someone at a distance whom you almost recognize as your acquaintance Bob, but you lose sight of him before you can be sure. If you had gotten a better look at the man and recognized him as Bob, then you would know that Bob was on the quad at 8:00am.7 As things stand, however, you do not know it. Still, you are not in the same position with respect to the proposition “Bob was on the quad at 8:00am” as you would be if you hadn’t seen what you did. Your experience on the quad gives you some reason to believe the proposition, without making you certain of it.

Notice that you might go on to use this proposition in arguments. Suppose, for example, that a bank robbery was committed in Manhattan at 8:03 and Bob was suspected of being behind the wheel of the getaway car. If you knew that Bob was on the quad at 8:00, you could be certain, via the following argument, that these allegations are false.