1. Quick Test (Bullet Point)
What is the difference between acquaintance, ability and propositional knowledge?
What is the difference between a proposition and a fact?
What does it mean to say that something has a real essence or is part of a natural kind of category?

2. Quick Test Acquaintance Knowledge Ability Knowledge
Propositional Knowledge
Proposition
Fact
Real Essence / Natural Kind
Real Definition

3. Key Questions / Lesson Objective:
What should we avoid when defining terms?
What do the terms necessary and sufficient mean?
What is the tripartite view of knowledge?

4. A Few More Things about Definitions…
If you remember back to last lesson we were discussing how to go about defining knowledge. We looked primarily at the work of Linda Zagzebski who in turn built on the writing of Locke.
Locke believed that a real definition (i.e. one that was unlikely to change) should be one that picks out the real essence of something (i.e. the thing that makes that object / being what it is). Zagzebski effectively agreed with this, except she used the term natural kind.

5. A Few More Things about Definitions…
It’s worth pointing out a few more key things about definitions here that we didn’t get chance to discuss last lesson:
What is the definition of a sunburn?
What is the definition of a table?
What is the difference between these two definitions?

6. Causal Definitions
Some definitions emphasise the cause of the thing being defined, whereas others do not. For example, a definition of sunburn outlines not just the symptoms but the cause as well (UV light). A definition of a table however, is more about how we use the object rather than how it came to be.
Zagzebski isn’t sure whether knowledge will have a causal definition (i.e. what brings it about) or something else, but she does not think the approaches are mutually exclusive. It could be possible to define knowledge correctly in ways that involve cause, and ways that do not.

7. Avoiding Faulty Definitions
Finally Zagzebski outlines the things she thinks a good definition should avoid:
Circular – It must not contain the term being defined.
Obscure – The definition should not be more complicated or confusing than the original term, otherwise what’s the point?
Negative – You can’t define a term by what it isn’t.
Ad Hoc – Your definition can’t be tailored to counter specific problems, it should be a general one that is usable by all.

8. Knowledge Defined
So, if we wish to go about defining knowledge (we do) what’s going to be the best way to do it?
The approach usually taken in philosophy (and indeed the one that Zagzebski endorses) is to try and figure out what conditions must be met for knowledge to be had. In other words, what is the difference between a state of affairs where someone holds a belief and a state of affairs where someone has knowledge?
A technical way of putting this might be to ask what conditions are necessary for knowledge, and what conditions are sufficient.

9. More Key Terms…
A necessary condition is something which has to be true for something else to follow, but may not be enough on it’s own.
A sufficient condition is one which, once it is achieved, is enough for something else to follow.

10. Necessary and Sufficient Conditions
Being at least 18 is a condition of being able to vote in Britain. What kind of condition is it? Why? Having your head chopped off is a condition for dying. Scoring more goals than the opposing team is a condition for winning a game of football.

11. Conditions for being able to vote in Britain:
Being human
Being aged at least 18
Being British
Being sane
Not being in prison
These are each individually necessary – they are all needed.
But they are also jointly sufficient – together they allow voting.

12. Task – are the conditions on the left necessary/ sufficient/ both/ neither for the things on the right?
Having three straight sides – being a triangle
Having a horn – being a unicorn
Needing a filling – going to the dentist
Having grandchildren – being a grandmother
Going to college – being a student
Killing somebody – being a murderer
Having more than three people – being a party
Being female – being a mother
Eating too much – being fat
Breaking the speeding limit in front of the police – being arrested

13. Task – are the conditions on the left necessary/ sufficient/ both/ neither for the things on the right?
Having three sides – being a triangle both Both
Having a horn – being a unicorn N
Needing a filling – going to the dentist Sufficient
Having grandchildren – being a grandmother N
Going to college – being a student Neither
Killing somebody – being a murderer N
Having more than three people – being a party Neither
Being female – being a mother N
Eating too much – being fat Sufficient
Breaking the speeding limit – being arrested Sufficient

14. With your partner:
What are the necessary and sufficient conditions of propositional knowledge?
Use the task on page 9 to help you.

15. From Socrates to Plato – Page 10-11
Having begun to think about the difference between belief and knowledge we can now see how some of the earliest philosophers handled this issue (Plato and Socrates). In Plato’s dialogue – the Meno, he tries to work out this very difference.
He starts out by showing that true belief and knowledge seem to have a lot in common, they seem to be equally as valid as guides for action.
He then argues that one key difference is the fact that true beliefs “run away from a man’s mind” and they need to be tethered by “working out reason” – essentially, Plato (through the character of Socrates) seems to think part of the reason we value knowledge is the fact it’s backed up by reason.
Finally Plato highlights (by contrasting a jury and an eyewitness) that this justification / reason usually comes from the method by which we acquire the knowledge.

16. Where does Plato lead us?
This definition of knowledge – also known as the Tripartite definition – stood fairly unchallenged until the 20th Century.
Justified
True
Belief
Each condition is individually necessary, and they are jointly sufficient.
S knows that P iff (if and only if):
S believes that P
P is true
S’s belief that P is justified

17. Justified True Belief
Which of the three conditions are met in each of the cases below? In which cases would we say the person truly has knowledge?:
John knows that Mary is cheating on him because he saw texts from another man on her phone. She isn’t, they were a wrong number.
Students know that Mike is going to put them in the study hall if they don’t do their homework because he has repeatedly told them.
Danielle knows vaccinating her children does more harm than good because half the diseases it is supposed to protect against are made up and some people on the internet talked about their bad experiences with vaccinations.
Mark knows there are aliens in the sky around Earth. Whilst he doesn’t have any evidence it actually turns out he’s right.
I know that if I fly in a straight line round the world I will eventually reach the same place I took off from.

18. Justified True Belief
Which of the three conditions are met in each of the cases below:
John knows that Mary is cheating on him because he saw texts from another man on her phone. She isn’t, they were a wrong number. JB
Students know that Mike is going to put them in the study hall if they don’t do their homework because he has repeatedly told them. JTB
Danielle knows vaccinating her children does more harm than good because half the diseases it is supposed to protect against are made up and some people on the internet talked about their bad experiences with vaccinations. B
Mark knows there are aliens in the sky around Earth. Whilst he doesn’t have any evidence it actually turns out he’s right. TB
I know that if I fly in a straight line round the world I will eventually reach the same place I took off from. JTB

19. Justified True Belief - Whiteboards
Can you give an example of justified true belief? Can you give an example of a true belief that isn’t justified? Can you give an example of a justified belief that isn’t true? Can you give an example of a belief that isn’t true or justified? Why is it more difficult to think of statements that are only justified or only true?

20. Justified True Belief - Discussion
We can raise two kinds of objection to the tripartite definition of knowledge by searching for counterexamples. The method of finding counterexamples is important in philosophy. If a theory makes a general claim, such as ‘all propositional knowledge is justified true belief’, we only need to find a single instance in which this is false to show that something is wrong with the theory. (Of course, we then have to find out what is wrong with it.)
The two potential objections to the tripartite view are:
Either one or more of the conditions are not necessary for knowledge.
The conditions together are not sufficient for knowledge.

21. Quick Reminder of the Spec
3.1.1 What is knowledge?
The distinction between acquaintance knowledge, ability knowledge and propositional knowledge.
The nature of definition (including Linda Zagzebski) and how propositional knowledge may be analysed/defined.
The tripartite view:
Propositional knowledge is defined as justified true belief: S knows that p if and only if:
1. S is justified in believing that p,
2. p is true and
3. S believes that p (individually necessary and jointly sufficient conditions)
Issues with the tripartite view including:
The conditions are not individually necessary

22. Homework
We said earlier that the JTB (tripartite) view of knowledge held fairly strongly until the 20th Century. This is because in the 1960’s a seminal philosophy paper was written by a man called Edmund Gettier that called into question the tripartite view of knowledge and seriously undermined it’s strength. Gettier used a series of counter-examples (or thought experiments) to show why he thought that the JTB definition was not sufficient (i.e. not enough) for knowledge. These became known as Gettier Problems.
Task: Identify and outline 1 Gettier (or Gettier style) counter-example / problem and explain clearly why it shows that justified true belief is not enough for knowledge.
Extension: Can you think of any replies to Gettier, either in a way that saves the JTB definition, or by redefining knowledge to deal with his counter-examples.

23. What have we covered this lesson?
Completed our discussion about definitions by mentioning causal definitions (i.e. sunburns) and what good definitions should avoid (circularity, obscurity, negative, ad hoc).
Looked at what it means for conditions to be necessary and sufficient.
Discussed what necessary and sufficient conditions there may be for knowledge.
Identified the tripartite view of knowledge (Justified true belief) as outlined by Plato.
Tested the tripartite view of knowledge.

24. What was our key question?
How well can you answer it?
How could you expand on your answer?
How good is your partner’s answer?
What can you do outside of lesson to improve your answer?