Gettier Cases

By Michael Gakuran | | Philosophy | Leave a comment |

fake-barn-countryGettier cases! Cases of our beloved Justified True Belief (JTB) account of knowledge gone wrong! Edmund Gettier famously gave several short examples of cases where I could have a true belief that was justified – all 3 of our conditions for knowledge – yet not actually know. How could this be!? Take a gander at a couple of examples.

    I’ve been gettiered!

The Stopped Clock

(Example from The Internet Encyclopedia of Philosophy)

Suppose that the clock on campus (which keeps accurate time and is well maintained) stopped working at 11:56pm last night, and has yet to be repaired. On my way to my noon class, exactly twelve hours later, I glance at the clock and form the belief that the time is 11:56. My belief is true, of course, since the time is indeed 11:56. And my belief is justified, as I have no reason to doubt that the clock is working, and I cannot be blamed for basing beliefs about the time on what the clock says. Nonetheless, it seems evident that I do not know that the time is 11:56. After all, if I had walked past the clock a bit earlier or a bit later, I would have ended up with a false belief rather than a true one.

Charlie’s book

An example of my own modified Gettier Case.

I have good evidence that suggests Charlie has a copy of ‘Epistemology: An Anthology’. I have seen him carrying it around, reading from it, making notes in it and I know he puts it away on his shelf every night before going to bed. So I form the justified true belief that ‘Charlie has a copy of Epistemology: An Anthology’. Unbeknownst to the both of us however, Charlie’s book is stolen from his bag as we eat lunch together one day by a rather poor philosophy student. But Charlie loves Philosophy so much that he has another copy of the book at home – one that he has never spoken of nor that I have seen. So am I still correct in my belief that Charlie has a copy of the book, but is it knowledge?

Most people agree, these sort of special examples spell real problems for our JTB account of knowledge. In the second case for example, my ‘knowledge’ of Charlie’s having the book seems to rest on justification that has been undermined (namely that the book I saw Charlie using was stolen). So, though logically the argument is still valid, it seems as though I need to add something else to the JTB account of knowledge to avoid being ‘gettiered’. What could I do?

    No essential false assumptions

We might just suppose all that is needed to keep our JTB account of knowledge intact is a further condition that would rid us of this gettierisation. We could add into our JTB account a fourth condition; that of no false assumptions:

(P4) S’s belief that p has no essential false assumptions.

For example, in the Stopped Clock case, I assumed that the clock was working properly. This assumption is essential because, as we can see, if the clock happens not to be working properly, my belief about the time would not be justified. But the assumption is false – the clock is not working properly – so our justification is lacking and hence we do not gain knowledge. Seems to work, right? Likewise, in my example, the mistake was the tacitly assume that Charlie only had one copy of the book.

Unfortunately, we can provide further examples that still cause problems:

Fake Barn Country

(Example from The Stanford Encyclopedia of Philosophy)

Another case illustrating that clause ([P4]) won’t do the job is the well-known Barn County case (Goldman 1976). Suppose there is a county in the Midwest with the following peculiar feature. The landscape next to the road leading through that county is peppered with barn-facades: structures that from the road look exactly like barns. Observation from any other viewpoint would immediately reveal these structures to be fakes: devices erected for the purpose of fooling unsuspecting motorists into believing in the presence of barns. Suppose Henry is driving along the road that leads through Barn County. Naturally, he will on numerous occasions form a false belief in the presence of a barn. Since Henry has no reason to suspect that he is the victim of organized deception, these beliefs are justified. Now suppose further that, on one of those occasions when he believes there is a barn over there, he happens to be looking at the one and only real barn in the county. This time, his belief is justified and true. But since its truth is the result of luck, it is exceedingly plausible to judge that Henry’s belief is not an instance of knowledge. Yet condition ([P4]) is met in this case. His belief is clearly not the result of any inference from a falsehood. Once again, we see that ([P4]) does not succeed as a solution to the Gettier problem.

So why not think that, as before, there is an essential false assumption in Fake Barn Country? Maybe the essential false assumption is that Henry is assuming he is not in Fake Barn Country? We could say this, but how plausible is it really? Henry would never have even considered that there was such a senario as Fake Barn Country, let alone that he was in it. Likewise in my example, just how practical is it to avoid assuming that Charlie only has one copy of the book? Most people usually don’t have more than one copy of the same book… So how can we avoid making these sorts of bizarre false assumptions? We’ll consider at least one possible theory: Nozick’s tracking account of knowledge. See Nozick’s truth-tracking for details.


What we can see from Gettier Cases is the need for something more than the standard JTB account of knowledge. Here we branch off into many wonderful different theories and approaches. It might help to think of them as falling under two different category headings: Externalism and Internalism. Both can be seen as trying to explain what the extra thing that we need to add to our JTB account of knowledge is, usually in terms of justification. Let’s go!

Sources: Lecture handouts written by my lecturer Daniel Elstein, The Internet Encyclopedia of Philosophy and The Stanford Encyclopedia of Philosophy

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