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. 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.

Map 15:

As things stand, however, you do not know Proposition 2, and so you do not know the conclusion, Proposition 3. But, because you have some reason to believe Proposition 2, you have some reason to believe the conclusion as well. Perhaps, then, you should go to the police and make a statement. If you do, how much weight should the police give to your testimony? Let’s consider some of the questions that they might ask you (and that you could ask of yourself):

For how long did you see him? At what distance? How good was the visibility? Did you focus on him, or was he in the periphery of your vision? How familiar are you with Bob’s appearance in the first place? Is it based on vision alone that you think you recognized him, or did you hear his voice as well, or smell that unusual cologne that he’s always wearing?"

In addition to these questions, you might also consider how distinctive Bob’s appearance is: is he someone who is easily recognized in a crowd, or someone who can easily be mistaken for someone else? Notice that for each of these questions there is a range of possible answers, and that how sure you could be that Bob was on the quad depends on where along that range your answer falls.

Another way in which you might have some reason to believe something without being certain of it is by remembering it vaguely. This would be the case with someone who did see Bob on the quad recently and recognized him but couldn’t recall with certainty when the encounter occurred. To get a sense of the considerations that are relevant to determining the epistemic status to this person of the proposition that Bob was on the quad at 8:00am we could make up a list of questions similar to those that we considered above for the case of seeing Bob on the quad. A third way that one might come to have an intermediate epistemic status with respect to a proposition is by inferring it from earlier propositions. In the example we’ve just been considering, your conclusion that Bob couldn’t have been behind the wheel of the getaway car, has such a status because it is inferred from uncertain premises. But, as was mentioned briefly earlier, there are inferences in which, even if the premises are certain, the conclusion cannot be inferred with certainty. Later, when we consider some of these types of arguments in greater detail, we will get a sense of the factors that would lead to the conclusions being nearer to or further from certainty.

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