What counts as knowledge: airport security as a test case

The United States government has revised its rules for allowing liquids on board airplanes: You can now bring on board 3 oz. plastic bottles, as long as they fit in a quart-sized sealable plastic pouch.

The emphasis on numbers and metrics shows that a certain kind of knowledge is in operation. Screening agents are not asked to exercise any expertise or insight; they simply take out their rulers and scales (not that this happens in practice, in my limited experience). Roughly the same reasoning applies to screening hand luggage: the idea is that every piece of luggage is screened, not just luggage attached to someone who arouses the suspicions of the security personnel.

There is also another kind of knowledge at work. Security personnel are trained to note suspicious behaviors (agitation, sweatiness, and so on). This checklist approach, however, is still meant to be mechanical: in theory a robot could apply it also. 

Finally, there is a more intuitive kind of knowing. “Why did you shadow that woman?” the supervisor asks the officer on the beat. “I just had a hunch,” is the answer.

There are good reasons for choosing the more mechanistic approach. Hunches can easily cover over prejudices. But the point I want to make is that when we choose the mechanical approach, we are actually choosing against knowledge. We are acting on our doubt that someone can be impartial without being forced to be so through the mechanical application of rules.

 The same holds true whenever we rely on rules, which choose the general over the particular, the manual over the situation “on the ground.” The democrat, wrote Plato, treats equal and unequal alike, which is a pretty good definition of what rules are all about. In our system of government, we say proudly that “justice is blind.” But we should also be acknowledging that blindness reduces the knowledge available to us.

Jack