objections to the tripartite definition of knowledge

Question 1

individually necessary conditions

Answer 1

that if X is not present then Z cannot occur

Question 2

why is justification not a necessary condition for knowledge

Answer 2

• I can know that P without knowing how/why I know it) (i.e. without a justification)
• For example, “John has a rare gift. If you give him any date in the future…he is able to tell you what day of the week this will be. He is unable to say how he does this, though he is always accurate” (H/J/C textbook).
  Some could claim that John has knowledge.

Question 3

why do some believe that justification is a necessary condition

Answer 3

• f a person bets regularly on horses, and says “I know that one day I’m going to have a big win,” we would not say that she knew what she claimed to know, even if one day she did have a big win. We might say that she believed that she would have a big win, but intuitively we think that such a case would not be an example of knowledge.
• There must be some sort of connection between the fact that the knower believes that p, and the fact that p is true. According to the JTB account, this connection is supplied by the idea of a good justification. The trouble with the gambler (from the point of view of knowledge) is that she has no justification for her belief that she will win.

Question 4

why is truth not a necessary condition for knowledge

Answer 4

• we used to know things that we now realise are not true
• For example, “Everyone knew that stress caused ulcers, [until] two Australian doctors in the early 80s proved that ulcers are actually caused by bacterial infection” (Hazlett)

Question 5

why do some believe that truth is a necessary condition for knowledge

Answer 5

The truth condition, says that you cannot know that something is true if in fact it is false. So if you are to know that p, then p must be true. Of course, p can itself be a claim that something else is false. For example, p might be “it is false that arsenic is nourishing” and I can certainly know that it is false that arsenic is nourishing. But here, what I know (namely that it is false that arsenic is nourishing) is something that is true. You can believe that something is true when really it is false; and you can also wrongly take yourself to know that something is true when in fact it is false. However, you cannot, according to this first condition really know something to be true if in fact it is false.

Question 6

why is belief not a necessary condition for knowledge

Answer 6

• I can know that p but not believe that p.
• For example, if I give multiple correct answers in a quiz but they feel like mere guesses to me we might say I know that P even though i do not believe that P.

Question 7

why do some believe the belief is a necessary condition

Answer 7

The mere fact that p is true does not guarantee that S knows it. There must be some connection between S and p. S must have some sort of mental relation to p. But this relation has to be of a certain kind. It is no use, for example, if she wonders whether p, or fears that p, or hopes that p. These are all attitudes which she might have toward p, but they are incompatible with her knowing that p. If she is to know that p, she must accept p is true, or, as the second condition says, she must believe that p.

Question 8

jointly sufficient

Answer 8

This means that if X and Y are present then Z must occur

Question 9

what shows that the conditions aren’t jointly sufficient for knowledge

Answer 9

the gettier cases

Question 10

what are the gettier cases

Answer 10

where there is a justified true belief, but where we would not say it was knowledge

Question 11

gettier case: case 1

Answer 11

1. Suppose that Smith and Jones have applied for a certain job. And suppose that Smith has strong evidence for the following conjunctive proposition:
   a) Jones is the man who will get the job, and Jones has ten coins in his pocket.
2. Smith’s evidence for (a) might be that the president of the company assured him that Jones would in the end be selected, and that he, Smith, had counted the coins in Jones’s pocket ten minutes ago.

• Proposition (a) entails [i.e. leads to]:

(b) The man who will get the job has ten coins in his pocket.

3. Let us suppose that Smith sees the entailment from (a) to (b), and accepts (b) on the grounds of (a), for which he has strong evidence. In this case, Smith is clearly justified in believing that (b) is true.
4. But imagine, further, that unknown to Smith, he himself, not Jones, will get the job. And, also, unknown to Smith, he himself has ten coins in his pocket.
5. Proposition (b) is then true, though proposition (a), from which Smith inferred (b), is false.
6. In our example, then, all of the following are true:
   1.(b) is true,
7. Smith believes that (b) is true,
8. Smith is justified in believing that (b) is true
9. But it is equally clear that Smith does not KNOW that (b) is true; for (b) is true in virtue of the number of coins in Smith’s pocket, while Smith does not know how many coins are in Smith’s pocket, and bases his belief in (b) on a count of the coins in Jones’s pocket, whom he falsely believes to be the man who will get the job.

Question 12

gettier case: case 2

Answer 12

1. Let us suppose that Smith has strong evidence for the following proposition:
   -(f) Jones owns a Ford.
2. Smith’s evidence might be that Jones has at all times in the past within Smith’s memory owned a car, and always a Ford, and that Jones has just offered Smith a ride while driving a Ford.
3. Let us imagine, now, that Smith has another friend, Brown, of whose whereabouts he is totally ignorant. Smith selects three place names quite at random and constructs the following three propositions:
   - (g) Either Jones owns a Ford, or Brown is in Boston.
   - (h) Either Jones owns a Ford, or Brown is in Barcelona.
   - (i) Either Jones owns a Ford, or Brown is in Brest-Litovsk.

• Each of these propositions is entailed by (f) [i.e. if (f) is true then these propositions are true].

4. Imagine that Smith realizes the entailment of each of these propositions he has constructed and proceeds to accept (g), (h), and (i) on the basis of (f). Smith has correctly inferred (g), (h), and (i) from a proposition for which he has strong evidence. Smith is therefore completely justified in believing each of these three propositions. Smith, of course, has no idea where Brown is.
5. ut imagine now that two further conditions hold. First, Jones does not own a Ford, but is at present driving a rented car. And secondly, by the sheerest coincidence, and entirely unknown to Smith, the place mentioned in proposition (h) happens really to be the place where Brown is.
6. If these two conditions hold, then Smith does not KNOW that (h) is true, even though

• (h) is true,
  Smith does believe
• that (h) is true
• Smith is justified in believing that (h) is true.

Question 13

gettier cases as a deductive argument

Answer 13

P1: If knowledge is JTB then it is impossible for someone to have a JTB which is not knowledge (If A then B)
P2: It is possible for someone to have a JTB which is not knowledge (B is false) - e.g. Smith’s beliefs in Gettier’s example
C: Therefore, knowledge is not JTB. (A is false)