Tuesday, 2 December 2014

A Case of Knowledge Based Upon False Belief

Avram Hiller
My name is Avram Hiller, and I am Associate Professor in the Department of Philosophy at Portland State University. I work in several different areas of philosophy in the analytic tradition. My work in epistemology concerns the nature of knowledge and, in particular, what the external environment must be like for an individual to have knowledge in it.

According to some theories of knowledge, it is impossible for someone to know something if the person’s belief is based upon a false belief. But an appeal to social aspects of belief formation casts this criterion into doubt. For it is not uncommon for a helpful individual to convey a point to someone else using a falsehood. Consider the following case, which appears in a recent publication of mine:

Natasha is a spy in the field. Messages to her from Headquarters often are detected by enemy intelligence, and Headquarters is aware of that. Today, Headquarters needs to communicate to Natasha that her contact will be at the train station at 4:00 pm, but Headquarters cannot directly tell her that. However, Headquarters knows that Natasha happens to have a false belief that the train from Milan is arriving at 4:00 pm. It really arrives at 8:00 pm; also, assume that there are no signs posted at the station indicating what time it will arrive. So Headquarters sends a communiqué to Natasha stating that her contact is on the train from Milan. She then forms the justified belief that the contact will be at the station at 4:00 pm (call this proposition C). C is true.

This case involves a peculiar form of testimonial evidence. Typically, one acquires knowledge via testimony when a cooperative testifier states truths. But this case maintains the spirit of knowledge via testimony – the testifier, Headquarters, is being epistemically cooperative in conveying a true target proposition to a Natasha, albeit in a somewhat unusual manner.

I submit that it is a case where Natasha knows that C, even though her belief is based essentially on two false beliefs. However, I should add that this particular case has some complications (which I discuss in the paper) and not all who hear the case take it to be a case of knowledge. At the very least, it is a case where Natasha is, to use a phrase introduced by Robert Nozick, tracking the truth of C. In other words, had the contact not been planning to arrive at that time, Natasha would not have formed the belief that the contact is at the station at that time since Headquarters would not have sent that communiqué to her.

On the account of knowledge I am developing, knowledge is justified belief which is formed in an environment which is conducive to believers forming true beliefs which are relevantly similar to the belief in question. This can happen when another person is somehow overseeing the epistemic environment for the purpose of conveying other truths to the believer, even if the overseer uses falsehoods to transmit the information. In the spy case – or so I claim – both Natasha’s belief was justified, and it was formed in an environment conducive to her forming a true belief about C. The fact that she believed that C via a falsehood does not undermine her knowledge of it.


  1. Does it follow then that for any pair of propositions < P, Q > where P is true & Q is false, there is some possible environment E such that an agent in E believing both that P and that Q could come to know that P via her falsely believing that Q?

    Or does the operative notion of Environment you employ separate out some subset of propositions (e.g., necessarily false) or require any such pair stand in a certain relation to one another (e.g., entailment or identity with respect to some coarse/fine grained individuation of the relevant states of affairs)?

    For example, suppose:
    P= The contact will be at the train station at 4pm
    Q= 9 is the smallest prime number
    Does your view at least in principle allow for there to be some E such that an agent can come to know that P via her falsely believing that Q? Or does being conducive to the formation of true beliefs make it the case that for there to be some such E requires a certain relation hold between the state of affairs described in P and that described in Q (broadly/narrowly construed): e.g., those having to do with the Milan-train, specifically its time of arrival and the identity of one its passengers (with primes or size comparisons thereof presumably not being among those)?

  2. That’s a nice thought and question. I’m not sure that it follows that for *any* , someone can come to know P via Q, but I don’t see that there is any theoretical reason why not. At the same time, I do think that there still is a justification condition on knowledge, and so someone who reasons, improperly, that 9 is the smallest prime number, and then that proposition is used in the service of gaining the truth that P, doesn’t know that P. And if someone reasons properly that 9 is the smallest prime number (say, a child is taught by a normally reliable but in this instance lying adult that 9 is the smallest prime) but then reasons improperly from that to P, then the person doesn’t know that P. So in order for someone to know P via Q, the environment would have to be such that the evidence to the agent really does support P. One can imagine a case where such a child is also told that the contact will be at the station when, if one takes the smallest prime as a PM hour and then subtract five hours from it, then I think the child may just know that P if the kid can do the subtraction. So there does have to be some relation between P and Q, presumably, since P has to be able to justify Q (in light of some other background beliefs).


Comments are moderated.