Notes for 2/25/2026

  

2/25/2026

[Philosophy Club every Monday, 4-5 pm, in the Buchtel College of Arts and Sciences room 436 ("The Cave")]

[Bioethics Club: Mondays from 5:30pm-6:30pm in Leigh Hall 408]

 

Can you think of a time when you thought you were wrong but turned out to be right?

 

Suppose we can agree on what level of justification is “good enough” to claim knowledge.

 

The JTB account of knowledge:

 

S knows that P if and only if the following conditions all obtain:

1.   S believes that P is true

2.   P is in fact true (you can’t know something that is false)

3.   S is adequately justified in believing that P is true

 

 

 

“The Gettier Problem”

 

 

The paper presents two counterexamples to the JTB analysis of knowledge.

 

Gettier’s case rests on the possibility of describing situations where a person’ belief is true, and their reasons would normally be “good enough” (justified) but in the case at issue the belief is in some sense only accidentally true (or true merely by luck).

 

Edmund Gettier’s counterexamples:

 

- Suppose that Smith and Jones have both applied for a job. 

- Smith has very strong evidence that Jones will get the job (suppose he overheard the company president say that the job will go to Jones).

- Smith also saw Jones give someone a dollar bill in exchange for ten dimes, which he then put in his pocket.

- Smith therefore is justified in believing that Jones will get the job, and that Jones has ten coins in his pocket.

- Smith therefore has strong justification for believing that the man who will get the job has ten coins in his pocket.

- But suppose that Smith is the man who will get the job (the company president had mixed up the names of Smith and Jones).

- Suppose, also, that Smith happens to have ten coins in his pocket, though he in unaware of this.

- So, it is true that the man who will get the job has ten coins in his pocket.

- Smith’s belief that the man who will get the job has ten coins in his pocket is justified, and it is true, but it seems wrong to say that Smith knows that the man who will get the job has ten coins in his pocket, since his belief is about Jones, who will not get the job.

(Trick that makes this work is ‘generalization’)

 

Gettier’s 2nd counterexample.

 

It is a truth of logic that if a statement A is true, then so is any proposition that has the form “A or B” (no matter what B is). [This is called the rule of addition in formal logic]

 

- Suppose Smith has strong justification for believing that Jones owns a Ford (he has seen Jones driving a Ford, wearing a “proud Ford owner” t-shirt...)

- Smith doesn’t know where Jones is, and thinks to himself, “maybe Jones is in Boston, of all places”.

- Smith thinks about the logical rule of addition, and thinks to himself, “well, at least I can know that either Jones owns a Ford or Jones is in Boston”.

- Suppose that Jones does not own a Ford after all (the car he has been seen driving is rented, and he bought the shirt at a garage sale for $0.25).

- Suppose, also, that by sheer coincidence Jones is in Boston.

- So, the statement “Either Jones owns a Ford or Jones is in Boston” is true, because Jones is in Boston.

- So, Smith’s belief is justified, and it is true, but it seems wrong to say that Smith knows that “either Jones owns a Ford or Jones is in Boston” is true.

(Trick is the ‘rule of addition’)

 

One of the first objections to Gettier’s paper highlighted the fact that in both of his examples, the person has a false belief that serves as the basis of the final true belief:

-      Jones has 10 coins in his pocket.

-      Jones owns a Ford.

 

It seems easy to fix JTB as follows:

S knows that P if and only if:

1.          S believes that P is true.

2.          P is in fact true.

3.          S is adequately justified in believing that P is true.

4.          S’s belief that P is not based on some other belief of S’s that is false.

 

 

 

But it didn’t take long for people to come up with examples showing this won’t work.

 

 

 

Here is my own example of a “Gettier case”:

-    Suppose I buy a box of cookies and put them in my desk drawer.

-    At 9:00 I leave my desk.

-    At 9:01, Zeke steals the cookies from my desk drawer.

-    Zelda sees this.

-    At 9:02, Zeke leaves his desk.

-    At 9:03, Zelda takes the cookies from Zeke’s desk and puts them back in my desk.

-    At 9:10 I return to my desk and think to myself, “There is a box of cookies in my desk drawer.”

-    My belief is true. There IS a box of cookies in my desk drawer. I am justified in believing this. My reasons for believing it are good enough for fallibilism.

-    But it doesn’t seem that I know there are cookies in my desk, because I don’t know about the theft and replacement of the cookies. (My belief is only true because I got lucky in how things turned out.)

 

Another example:

 

(This is a realistic fake sheep) 

 

-    Ferd buys 100 fake life-sized sheep and puts them out in his field.

-    Ferd’s neighbor, Gerd has a flock of real sheep.

-    One day, one of Gerd’s sheep wanders into Ferd’s field.

-    Herd is out walking, looks into Ferd’s field, and sees Gerd’s sheep.

-    Herd believes he is looking at a live sheep.

-    Herd’s belief is true, and his reasons for believing it are good enough for fallibilism.

-    But it doesn’t seem Herd knows he is looking at a real sheep (his chances of looking at a real sheep are only 1 in 101 – his belief turned out to be true only by luck).

 

 

 

It is common for people to overlook the fact that a counterexample to the JTB analysis requires that the belief the person holds has to actually be true as well as justified. It doesn’t work if someone holds a justified belief that is actually false.

 

 

 

 

Despite the difficulties of Gettier cases, few philosophers advocate returning to infallibilism.

 

It seems that there is an easy fix which is just to add that S’s belief can’t be accidentally true:

 

S knows that P if and only if:

1.   S believes that P.

2.   P is true.

3.   S is justified in believing P.

4.   S’s belief that P is not true only by accident (or luck).

 

But it is unclear what being “true only by accident” means.

 

If a waiter drops a tray and I witness it, I believe the waiter has dropped a tray, it’s true, I’m justified, but isn’t it only true by accident?

 

Well, that’s not what “accidentally true” means, right?

But then what DOES it mean?

 

Suppose that in the cookie theft case, Zelda plans to steal Zeke’s cookies, but is deterred by the fact that Zoe is near Zeke’s desk (which is very unusual for her). My cookie belief (Zeke has cookies in his desk today) is true only by virtue of good luck.