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A Beginner's Guide

Robert M. Martin

  1. 192 pages
  2. English
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eBook - ePub


A Beginner's Guide

Robert M. Martin

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About This Book

How do you know what you know? Epistemology is the philosophical study of knowledge. Without knowledge, scientific enquiry is meaningless and we can't begin to analyse the world around us. What is knowledge? How do you know you are not dreaming? Should we trust our senses? Presuming no prior experience of philosophy, this book covers everything in the topic from scepticism and possible worlds to Kant's transcendentalism. Clear and readable, Epistemology: A Beginner's Guide is essential reading for students and aspiring thinkers.

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Defining ‘knowledge’

Senses of ‘know’

The first question we ought to think about is: what, exactly, is knowledge? That is, when is it proper to say that someone knows something? What we’re after, here, is an account of what it takes to be knowledge. Sometimes it’s thought that to give this account we must provide a set of conditions that are individually necessary and jointly sufficient.
A condition is necessary for being x when something can’t be x unless it satisfies that condition. Being female is a necessary condition for being your sister; nobody could be your sister unless that person is female. A single condition is sufficient for x when anything that satisfies that condition would be an x. Being a daughter of your aunt is sufficient for being your cousin (but notice that it’s not necessary). Two or more conditions are jointly sufficient for x when anything that satisfies all those conditions would be an x. These conditions: being female and having the same parents as you do, are jointly sufficient for being your sister. Anyone who satisfies both these conditions is your sister.
The noun ‘knowledge’ and the verb ‘to know’ are used in a large variety of ways. The Oxford English Dictionary devotes almost 2600 words to defining various senses and constructions involving the verb (not including hundreds of examples). It’s difficult to sort all this out, but we can roughly distinguish three main kinds of ways of knowing, corresponding to three sorts of things said to be known:
1 Knowledge of facts (for example, Fred knows that the party is cancelled). We’ll call this knowing-that.
2 Knowledge of a thing or person (for example, I know Sally; Irving knows every song the Beatles recorded). We’ll call this knowing-him/her/it.
3 Knowledge how to do something (for example, Zelda knows how to string a guitar). We’ll call this knowing-how.
This may seem very clear and straightforward, but even here, at the very beginning of our subject, what seems obvious may not be correct, and it’s not easy to say what really is correct. First, let’s look at a sample of some of the meanings ‘know’ can have; see if you can sort them into those three categories.
You can be said to know when:
you can distinguish between two things
you can perform an action
you’re acquainted with something
you’re aware of a fact
you’re aware of a thing
you’re able to identify someone
you’re able to reidentify someone you’ve seen earlier
you’re familiar or intimate with someone
you have information about something
you have learned something
you have practical understanding of something
you recognize a statement as true.
Can you sort these into the three categories? It’s difficult, maybe impossible. Maybe the three categories aren’t inclusive enough.
Next, think about what might be involved in sense 2. When you say that you know Sally, what exactly does that mean? Well, it can mean that you can recognize her when you see her; or that you know that she’s intelligent, moody, and creative; or that you know how to cheer her up when she’s down; or a number of other things. Knowledge in sense 2, then, can involve knowing-that and knowing-how. Is it ever (or always) entirely a matter of knowing-that plus knowing-how?
Now think about 3. What is it to know guitar-stringing? Perhaps this case of knowing-how is actually a matter of knowing-that (sense 1). Zelda knows that the strings need to be inserted into the pegs with the loose end under the winding, that the thickest string goes on the top end, and so on. Are some cases of knowing-how just cases of knowing that?
What we have noticed here is that some cases of 2 may really amount just to cases of 1 or 3, and that some cases of 3 may really amount just to cases of 1. This suggests that we don’t really need three categories at all: maybe all knowing is just a case of knowing-that, category 1.
But on the other hand, there do appear to be cases of 2 and 3 that can’t eventually be collapsed into case 1. Consider this example of case 2: ‘Seymour knows the fragrance of hyacinths.’ This may amount to knowing how to identify that fragrance, to name it and pick it out from other similar ones, but it doesn’t seem at all to be a case of knowing-that.
And consider this example of case 3: ‘Lucy knows how to whistle.’ This sort of knowing-how appears to have nothing to do with any knowledge in senses 1 or 2 at all.
Almost all the philosophical tradition in epistemology concentrates on knowing-that – sense 1. Why this concentration? It has been claimed that it’s the basic kind, and that other sorts of knowledge boil down to it – that is, that they can be understood wholly in terms of knowing-that. But you may find this implausible after having thought about all the different ways of knowing we’ve just mentioned. It could be, instead, that this is the most important kind of knowledge; but it’s not clear why this might be so. Another possibility is that this kind of knowledge involves the most interesting puzzles and complexities. But the answer may be simply that the earliest philosophers chose this sort of knowledge to talk about and the later ones read them, and thought about what they said, and added their own thoughts, and so a tradition was set up of this sort of consideration, without any real reason for excluding other sorts.
Anyway, we’ll follow the tradition by concentrating on knowing-that.


Philosophers think of knowing-that as the kind of knowing whose object is a proposition. What’s a proposition? Think of it as what a sentence means, what it expresses. So when two different sentences – sentences that differ in component words, or word order, or language – have the same meaning, they express the same proposition. So a single proposition is expressed by ‘Fred loves Sally’ and ‘Sally is loved by Fred’ and ‘Fred liebt Sally.’
Propositions are expressed by a whole declarative sentence, rather than, for example, just a noun or noun phrase. ‘Fred loves Sally’ is a declarative sentence, and expresses a proposition. When Marvin knows that Fred loves Sally, this proposition is the object of his knowledge. It’s a case of knowing-that. ‘Sally’ and ‘football’ and ‘who Sally is’ and ‘how to reach Sally by telephone’ are not whole sentences – they’re merely nouns or noun phrases. They do not express propositions. So when Marvin knows Sally or knows football, or knows who Sally is, or knows how to reach Sally by telephone, the object of his knowledge is not a proposition; these are not cases of knowing-that.
A noun is, roughly, a word that names something or a group of things: ‘Arnold’ and ‘ducks’ in ‘Arnold is afraid of ducks.’ A noun phrase is one or more words that function that way: ‘Deciduous trees’, ‘their leaves’, and ‘autumn’ in ‘Deciduous trees drop their leaves in autumn.’ A declarative sentence makes a statement, by contrast with, for example, ‘Hello!’ or ‘Please pass the salt’ or ‘When’s lunch?’
Another way to think about knowing with a propositional object is to notice that the object, the thing known, is something that’s either true or false. If Fred loves Sally, the proposition expressed by the words ‘Fred loves Sally’ is true; if he doesn’t, it’s false. The contrast here is again with the other two senses of ‘know’, in which it doesn’t make sense to say that what’s said to be known is either true or false. Sally (whom Fred knows) is neither true nor false, and neither is football, or who Sally is, or how to reach Sally by telephone.
Sometimes we want to say that a declarative sentence expresses a fact. ‘Christmas day occurred on Wednesday in 2002’ expresses the fact that Christmas day occurred on Wednesday in 2002. ‘It’s raining in Peru’ expresses the fact that it’s raining in Peru – but only if that really is a fact. If it isn’t raining in Peru, that sentence doesn’t express a fact. Facts are never false. If a sentence is false, it doesn’t express a fact. (It only purports to express a fact.) Because the object of supposed knowledge, what’s said to be known, might be false, we say that the object is a proposition, not a fact.

Knowledge and truth

Now suppose that it’s false that Fred loves Sally. That must make it false that Matilda knows that Fred loves Sally. If the propositional object is false, then any claim that somebody knows that propositional object must be false. This is just a matter of the conventional language use here. We don’t say that something is known when we think it’s false. To say that something is known is to imply that it’s true. Of course, sometimes people say that they or somebody else knows something, but what’s said to be known is false. That means that what they say is false. If Shirley said, ‘Arnold knows that World War I ended in 1919’, what Shirley says is false: Arnold doesn’t know that, and you can tell Arnold doesn’t know that without knowing anything about Arnold. (You don’t even have to know who he is.) The reason is that the propositional object, that World War I ended in 1919, is false. It ended in 1918. So nobody can know that propositional object. Philosophers say: Truth is a necessary condition for knowledge. That means: if it ain’t true, it ain’t knowledge. Or, to use the letter abbreviations that philosophers are so fond of when they express a general formula: The truth of p is a necessary condition for S knows that p.
‘Know’ is thus what’s called a factive verb. That means that the verb is used only when the speaker thinks that the embedded proposition is true. Other factive verbs are ‘realize,’ ‘learn,’ and ‘remember’. You wouldn’t say ‘I remember that I went to the zoo on my fifth birthday’ if you didn’t think that you did go to the zoo on your fifth birthday.
Perhaps you have thought of this objection: it’s not necessary for someone’s knowing something that what they believe is true. We only expect that they’ve made a significant effort to find out that their belief is true. That is, their belief isn’t just a prejudice, or a hunch, or a guess. That would make it merely a belief.
But there does seem to be a good reply to this analysis. Consider this example:
Cynthia has made a very thorough and careful search of every room, and announces that she knows that her lost keys are nowhere in the house. Suddenly you notice her keys in a very unlikely spot, say underneath the refrigerator.
Would you still say that she knew that her keys were nowhere in the house? The answer seems to be no. She was entitled to say what she did; she did what she was supposed to do. She didn’t jump to an unwarranted conclusion; she exercised due diligence in finding out the facts. But nevertheless, she didn’t know that the keys were nowhere in the house, because what she believed (and claimed to know) was false. She didn’t know what she said she knew. The distinction here is between two sorts of false belief: a false belief which just comes to you, a guess, without appropriate effort to determine its truth; and a false belief made after an appropriate and reasonable attempt to find out the truth. People who allow themselves the first sort of false claim are, in a way, failing to live up to their responsibilities, belief-wise; those who take more care with their beliefs are doing what they should. But either way, if a belief is false, it isn’t knowledge.

Knowledge and belief

But if a belief is true, it doesn’t follow that it’s knowledge. Just because it’s true that World War I ended in 1918, it doesn’t follow that Arnold knows that World War I ended in 1918. Maybe Arnold doesn’t know that because he doesn’t even believe it. Maybe he believes it ended in 1919, not 1918, or maybe he doesn’t have any beliefs at all about when World War I ended. Or maybe he’s a product of today’s educational system, and he’s never heard of World War I, so he has no beliefs at all about it. In order for Arnold to know that p, he has to believe it. Philosophers say: Belief is a necessary condition for knowledge; or S believes that p is a necessary condition for S knows that p.
The idea that knowledge involves belief is widely accepted among philosophers, but if you’ve had any experience with philosophy, you’ll be aware that no matter how obvious and well-accepted something is, there’ll be some philosophers who argue against it. That’s the case here too.
The first argument we’ll look at – briefly – involves examples such as this one:
Abigail is very fond of her twin sister Aileen, but the sisters haven’t seen each other for ten years, because Aileen has been working in a far-off country. It’s Abigail’s thirtieth birthd...

Table of contents

  1. Cover
  2. Title
  3. Copyright
  4. Contents
  5. Acknowledgments
  6. Introduction
  7. 1 Defining ‘knowledge’
  8. 2 Strength of belief and evidence
  9. 3 Justification and Gettier problems
  10. 4 Internalism, externalism, and justification
  11. 5 Foundationalism and coherentism
  12. 6 A priori knowledge, analyticity, and necessity
  13. 7 Knowledge based on sense-experience
  14. 8 Scepticism
  15. 9 New approaches to epistemology
  16. Further reading
  17. Index