How testimonial exchanges can fail

Before we explore how testimony can go wrong, we should consider the basic anatomy of a testimonial exchange. For Jonathan Adler (2012), the core cases of testimonial exchange involve two strangers (with no prior engagement with each other)—one person giving the testimony (let's call this person SPEAKER) and another person receiving the testimony (let's call this person HEARER).

Now we can begin to see specific ways testimonial exchanges can go wrong. Assuming that the goal of testimony is for a given hearer to acquire knowledge through the utterance of a given speaker, testimonial exchanges go wrong whenever the hearer does not acquire knowledge from the speaker's utterance.² With the basic anatomy of testimony noted above, I think we can highlight four general areas where testimony can go wrong: (i) with the hearer, (ii) with the speaker, (iii) with the utterance “p”, and (iv) with the general environment. Let's now consider an example of each.

Obviously enough, if there are significant problems with a given hearer—if, for example, the hearer is severely inebriated—then the hearer won't be able to acquire knowledge from the speaker's utterance that p. Consider the following case:

BAD HEARER: HEARER is visiting Chicago. While walking down the street, she sees SPEAKER, an ostensibly normal looking stranger, and asks for directions to the Willis Tower.

Given HEARER's deep confusion about Chicago skyscrapers, when she asks for directions to the Willis Tower we might wonder whether or not she is really looking for the Willis Tower. And even if SPEAKER gives HEARER flawless, clear, and precise directions, it's not clear that she can acquire knowledge from these directions because she is so very confused about which buildings are which in downtown Chicago.

Additionally, if there are significant problems with a given speaker—if, for example, a given speaker is severely intoxicated or otherwise rendered sufficiently unreliable—then anyone who hears that speaker's testimony will be unable to acquire knowledge from it. Consider another case:

BAD SPEAKER: HEARER is visiting Chicago, and wants to visit the Willis Tower. While walking down the street, she sees SPEAKER, an ostensibly normal looking stranger, and asks for directions. SPEAKER gives HEARER what sounds like plau­sible directions; however, SPEAKER is deeply confused about the names of Chicago skyscrapers—regularly, for example, confusing the Willis Tower for the Trump Tower. As such, it is not at all clear that HEARER can know how to get to the Willis Tower from SPEAKER's testimony, because there is a real chance that SPEAKER is confus­ing the Willis Tower with the Trump Tower.

Given SPEAKER's deep confusion about Chicago skyscrapers in BAD SPEAKER, any tes­timony about those skyscrapers—including testimony regarding how to get to them—seems undermined. SPEAKER, in this case, is not a reliable source of testimonial knowledge about Chicago skyscrapers.

Naturally enough, another way that a given testimonial exchange can go wrong is if the testimony, the assertion itself, is a bad one.

BAD ASSERTION: HEARER is visiting Chicago, and wants to visit the Willis Tower. While walking down the street, she sees SPEAKER, an ostensibly normal looking stranger, and asks for directions. SPEAKER gives HEARER what sounds like plausi­ble directions. On this occasion, however, SPEAKER—who is normally a very reli­able and helpful giver of directions—decides to sow some chaos in the world and give HEARER directions to the town dump instead of directions to the Willis Tower.

Given that SPEAKER gives HEARER false information regarding the location of the Willis Tower, HEARER simply cannot acquire knowledge as to how to find the Willis Tower from SPEAKER's testimony. Speaking falsehoods, obviously enough, undermines the transferal of knowledge, given that knowledge that p requires that p be true.

How can an environment inhibit the acquisition of knowledge in a standard case of testimo­nial exchange? Consider the following case:

BAD ENVIRONMENT: HEARER is visiting Chicago, and wants to visit the Willis Tower.While walking down the street, she sees SPEAKER, an ostensibly normal look­ing stranger, and asks for directions. Unbeknownst to HEARER, however, nine out of ten Chicagoans are deeply put off by the Sears Tower's name being changed to the Willis Tower. So much so, in fact, that if asked for directions to the ‘Willis Tower,' nine out of ten Chicagoans will actually give directions to the town dump in protest. SPEAKER, as it happens, is not one of those Chicagoans who is put off by the name change; so when SPEAKER is asked for directions to the Willis Tower, she reliably gives directions to the Willis Tower.

There's nothing wrong with HEARER or SPEAKER in BAD ENVIRONMENT. And SPEAKER gives good testimony, she gives HEARER good directions to the Willis Tower.Why should we be hesitant to grant HEARER knowledge in this case? Because, like the protagonist's belief in FAKE BARN cases, her correct belief (regarding the location of the Willis Tower) is extremely lucky. She could have very easily asked any of the other Chicagoans on the street, the majority of which would have given her directions to the town dump instead of the tower.

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