There’s a lot of exciting work being done on epistemic norms lately, including the norms of action. What I’m about to discuss clearly relates, in one way or another, to a lot of that work. But I’m not going to make the connections explicit here — I’ll save that for another time.
The principle I’m interested in is this:
Knowledge Suffices for Action (KSA): If you know that Q, then you may act as if Q.
This is intended as a necessarily true generalization.
I think the greatest threat to KSA comes from cases where you know that Q, something important turns on whether Q, and double-checking is very easy and nearly costless. For instance, consider this case.
(VIAL) Dayna is a medical doctor called to the scene, where a snake-bite victim lies unconscious. It will soon cause the victim serious pain if she gives him the wrong antivenin. The park ranger called and told Dayna all the relevant details just minutes ago over the phone. The ranger clearly saw that it was a cobra that bit the victim. So Dayna brought the cobra antivenin. Dayna remembers that it is cobra antivenin in her pocket (she just placed it there a couple minutes ago, and there’s nothing else in her pocket). The ranger has a simple test kit, which in just one minute can be used to double-check that it is cobra antivenin. The victim was just bit, and it will take hours before any harm comes to him. Dayna kneels down to treat the victim, sees that it is a cobra bite, pulls the vial of antivenin from her pocket, and . . .
So here’s the question. Is it okay for Dayna to just administer the antivenin without double-checking? Double-checking would consist of placing a drop of the liquid into the simple, quick, perfectly reliable, and easily available test kit.
My take on this case: (A) Dayna knows that it’s the cobra antivenin (in virtue of remembering that it is), (B) it’s not okay for her to administer the antivenin without double-checking, and (C) double-checking is not a way of acting as if it is the cobra antivenin.
What do you think?