AS Philosophy - Theory of Knowledge - Unit 4: Knowledge, Belief and Truth
AS Philosophy
Module 1
The
Theory
Of
Knowledge
Unit 5
Knowledge, Belief and Truth
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AS Philosophy - Theory of Knowledge - Unit 4: Knowledge, Belief and Truth
“What is Truth? Said jesting Pilate, and would not stay for an answer.”
Of Truth, Essays or Counsels Civil and Moral, Francis Bacon.
Definitions of Truth
In the gospel of John in the New Testament (18:28-40), Jesus is brought up before Pontius Pilate, the
Roman governor of the region. Pilate, a practical and worldly man, is bemused as to why Jesus has
been brought before him: what has he done?
During a brief exchange between Pilate and Jesus, we see two distinct concepts of truth at work. On the
one hand, Jesus has a very firm idea (18:37):
“You are right in saying I am a king. For this reason I was born, and for this I came into the
world, to testify to the truth. Everyone on the side of truth listens to me.
To which Pilate merely replies: “What is truth?” – as if to say, “You think truth exists independently of
everyone as a standard by which we can judge our beliefs?”
This sort of debate has been central to philosophy for centuries. We will now look at different theories
of knowledge, truth and belief.
What is Knowledge?
There are a number of different ways in which the verb „to know‟ is used. I can know someone‟s voice,
a piece of music or my own mind. However, this sort of knowledge seems less specific than factual
knowledge: I can know someone‟s voice or face without necessarily being able to put a name to it; I
may change my mind.
Factual knowledge usually entails knowing that something is the case. It is also called propositional
knowledge because it can take the form of a logical proposition. For example, “Wales‟ rugby team is
not as good as it once was” proposes a fact. It is something which might either be true or false.
Knowledge by Description and Acquaintance
Bertrand Russell identified two main types of knowledge: knowledge by description and knowledge by
acquaintance. The second of these we might also call "propositional knowledge". In other words, I
know that something is true (or false). These sorts of statement can therefore always be phrased in the
following way: "I know that X is true" (where X is a statement such as "John is bald").
The other type of knowledge is different in the sense that it cannot be put into the same sort of form.
For instance, if I say, "I am in pain", it is not the same as knowing some sort of detailed medical
account of your pain. Similarly, saying "I know how to ride a bike" is not the same as saying, "I know
that to ride a bike you need to push the pedals round and turn the handle bars". The distinction here is
between being acquainted with direct sense experience (pain, balance and co-ordination, a friend‟s
face) and inference (“I know the chemical composition of citric acid”).
Exercise
Which of these two different types of knowledge – if either – do you feel are less certain? Does the fact
that many statements which claim knowledge by acquaintance cannot be completely translated into
knowledge by description make them less or more certain?
Knowledge and Belief
Although sometimes the words „know‟ and „believe‟ are used interchangeably, in a strict sense they are
very different. Probably, no one would criticise you for saying, “I believe it‟s time for us to go” when
you actually mean simply, “It‟s time for us to go”.
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However, belief frequently implies that there is something you are either unsure of or for which there is
insufficient proof. For instance, I might say, “I believe that a European single currency is a good
thing”, or “I believe that Wales will win next Saturday”. These things may very well be false: the
single currency may prove disastrous, and Wales – judging on recent form – may very well lose.
Knowledge, on the other hand, in its strict sense, only applies to things that are true. Therefore, it may
be inappropriate to say, “I know that Wales will win” or that “I know which horse will win the 3:30 at
Kempton”, because there is an element of doubt involved (unless I have some proven psychic ability,
such as Mystic Meg).
Exercise
Try to think of a sentence which meets one of these three categories (belief, knowledge by
acquaintance or knowledge by description) then write it down in the first column of the box below,
labelling the type of knowledge it represents in the next column (go for 2 or 3 examples of each type).
I have put in a few examples of my own to start you off.
Sentence Type of Knowledge
I am in pain. Acquaintance
Paris is the capital of France. Description
Wales will win the Triple Crown this year. Belief
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Conditions of Knowledge
The first philosopher to define knowledge was Plato, who stated that for us to say that we know
something:
1. It must be true.
2. We must actually believe it (it must be consciously held).
3. There must be sufficient evidence for it (it must be justified).
Therefore, we may say that knowledge is „true justified belief‟.
True
Knowledge
Believed Justified
Exercise
Using the following table, think of things that fit these criteria in different ways (true but not justified
belief, untrue but justified, etc.). Place a tick under the appropriate column heading as you go.
Statement True? Justified? Believed?
How does this tripartite (3-part) definition of knowledge hold up? Have you identified any problems
with it? Before going further we need to look at some useful terms.
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If and only if
Like our use of the words „knowledge‟ and „ belief‟, the word „if‟ has different uses. Sometimes when
we use it we only want to convey a loose connection between statements: “I will come with you to the
pictures if you go on Friday”. In this example, the two statements – your going to the cinema, my
coming with you – are not absolutely connected. I may go to the cinema with you on another evening if
you suggest it – in other words, other things are possible.
However, if I say, “I will come with you to the pictures if, and only if, you go on Friday”, I am
excluding other possibilities (such as going on Tuesday). This distinction is important for philosophers
because it allows them to be more precise about the relationship between certain statements.
Exercise
Indicate which of the following are examples of „if‟ and which are examples of „if and only if‟.
Statement If If and Only If
I will die if I stop breathing
I can make a hot cup of tea if I have hot water
I will pass my exams if there is a miracle
If I eat any more I will be sick
Necessary and Sufficient Conditions
When we talk of something being true „if and only if‟ something else is true, this can happen in one of
two ways. For instance, if we take the example, “I will grow up to be strong and healthy if I exercise
and eat sensibly”, in what way might this be true? Will I be strong and healthy only from eating
sensibly and exercising? Or can these things be achieved in other ways?
So, in this example:
1. These would be necessary conditions for health if it could not be achieved without them.
2. These would be sufficient conditions for health if that were all that were needed to be
done in order to be healthy.
Another example might be learning to drive. Passing my theory test is a necessary condition of getting
a driving license, but it is not a sufficient condition (you also need to pass your practical test).
Exercise
Take the following situations and list both necessary and sufficient conditions for something to be the
case in each of them. The first example is given for you.
Situation Necessary Condition Sufficient Condition
Learning a foreign Having a source of Learning vocabulary and
language vocabulary (foreign applying it using correct
language speaker or grammar
dictionary)
Riding a bike
Meeting a friend for a
drink
Getting up in the morning
at 7am
Making a cake
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Gettier Problems
In 1963, the philosopher Edmund Gettier published an article in the Journal Analysis called “Is
Justified True Belief Knowledge?” The article, although quite short, had a profound effect on
epistemology by challenging the long-held traditional definition of knowledge as proposed by Plato
almost two and a half thousand years before.
Gettier‟s objections go something like this. Imagine a situation where all the traditional conditions for
knowledge were fulfilled – and yet you could not say that it constituted knowledge. For instance, take
the following situation:
1. Fred believes that Sam is in his room;
2. Fred sees Sam in his room;
3. Sam is in his room.
This fulfils the traditional conditions of knowledge. Sam is in his room, Fred believes that he is and is
justified in doing so by the experience of seeing him there. However, unknown to Fred, what he sees in
Sam‟s room is not Sam at all, but his twin brother Tim. However, Sam is actually in the room but is
just out of sight (e.g. he is hiding under the bed).
From this point of view, it would appear that Fred is right, but only by coincidence. Sam is in the room
(albeit under the bed), Fred is justified in believing he is, except that it cannot be said to be a genuine
case for knowledge because Fred is only correct through coincidence. Does this mean that the tripartite
definition of knowledge is incorrect?
Exercise
Can you think of any other situations in ordinary life where it might be said that the tripartite
conditions of knowledge were met, and yet you would not say that someone actually had knowledge?
Try to list 3 examples.
Responses to Gettier
There have been 5 main attempts at trying to repair the damage made to the tripartite theory by
introducing another condition to the triangle (making it a square). These are as follows:
1. No False Belief Condition: Beliefs cannot be based on a false belief. This attempt argues that no
knowledge can be claimed if it relies on a false belief. So, in our example, it is false that Fred is
actually looking at Sam.
2. Defeasibility Condition: Something is known as long as there is no evidence to the contrary. This
is a common sense view, argued by Keith Lehrer and Thomas D. Paxson, which argues that Fred
would be perfectly entitled to claim that he knows that Sam is in the room because he is not
aware of anything to the contrary. In other words, there is nothing to "defeat" the claim -
"defeasibility" meaning "capable of being defeated". Another example would be the flat earth
theory, or the concept that the earth was the centre of the universe. These were once claimed as
knowledge by the majority of people – until further knowledge arrived to prove that a different
case is true.
3. Reliability. This theory proposes that justified true belief should be obtained through a reliable
method. Therefore, if I believe that Sam is in the room but I am also aware that my method of
checking is not wholly reliable (or that I am aware that there are more reliable methods), then I
cannot claim knowledge in this instance.
4. Conclusive Reasons Condition: A reason must exist for the belief that would not be true if the
belief itself were false. This was first put forward by Fred Dretske. If, for example, I believe that
there is a chair in front of me, the reason for believing that it is there would not exist if the belief
were false (that is, if the chair were not there).
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5. Causal Connection Condition: There must be a causal connection between the knowledge and the
belief. This argument, first put forward by Alvin Goldman, states that a belief must have an
appropriate connection to the knowledge claimed. In our example, Fred should not be able to
claim that he knows Sam is in the room because there is no „appropriate connection‟ between his
viewing Tim (Sam‟s twin brother) and his conclusion that Sam is in the room.
Exercise
Are there any problems with any of the above theories? Take each in turn and see if you can think of
how they might be criticised.
Analysis of the Responses
Each of the 5 different responses admits that Gettier has highlighted a problem, and each seeks to
resolve it by adding another condition to knowledge. So, what was a tripartite division becomes a four
–part one. You could also think of this as moving from a triangle to a square.
True
Knowledge
Believed Justified
True Extra
Condition
Knowledge
Believed Justified
Let's now look at each of the responses in turn:
1. No False Belief Condition. This response argues that we cannot be said to know anything if it is
based on a false belief or on a group of beliefs of which one is false. So, in the example we have
been considering, I cannot be said to know that Sam is in the room because my "knowledge" is
based on the false belief that I am seeing Sam (whereas I am actually seeing Tim). So, adding this
as an extra condition seems to work, doesn't it?
The main problem with this theory is that it seems to deny things that we would say that we know.
For instance, I may claim to know a certain piece of information because my friend Bob told me.
However, I might also believe that Bob is trustworthy because he has never lied to me - which may
turn out to be false. In this way, although Bob is not lying in this instance, my belief that Bob has
never lied to me is false. However, is this really a reason not to say that we don't really know that
what Bob has said is true? In this case the rule seems too harsh. What if I had other information
that agreed with what Bob said (so that I have other evidence for the truth of the statement)?
According to this theory, my false belief that Bob has never lied to me means that I cannot claim
that I know this piece of information.
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A comeback to this criticism is to say that only if the false belief is relevant to the knowledge
being claimed does it mean that the claim does not really constitute knowledge. But what if I hold
a belief that relies on something being true even though I do not consciously believe it? For
instance, imagine that I am due to meet Jane at 7pm. Imagine now that Jane's lift lets her down and
she has to catch a bus. Is my belief that I will meet Jane at 7pm a case of knowledge? I do not
consciously hold the belief that she is getting a lift, so I am not wrong about that. However, can I
really say that I know she will be there?
2. The Defeasibility Condition. This response argues that the extra condition should be that there is
no information that would count against the justification. So, in the case of Fred and Sam, the fact
that Tim was in the room should really count against the claim for knowledge.
However, think of this example:
I think that Jim is at home because he is usually at home at this time. However, unknown to
me, Dave has called Jim to go out to play squash (an offer I know Jim would normally
accept). However, also unknown to me, Jim has just fallen over and sprained his ankle, so he
cannot play.
In this example, can I say that I know Jim is at home? From the point of view of the defeasibility
condition, there exists a fact that if it was true - Dave calls Jim to play squash - would "defeat" my
knowledge that Jim is at home. However, the other fact - Jim has just sprained his ankle - means
that he does not play and is therefore at home.
The problem here seems to be that either I say that I do know that Jim is at home - in which case
we are left with the same problem as earlier examples (it just happens to be true) - or I have to
admit that the simple existence of a fact that would defeat the initial belief is not enough. In either
case the defeasibility condition seems to be problematic.
3. Reliability. The main problem with this approach lies in what we mean by reliability. What defines
a reliable method? A sceptic would point out that a method that we consider reliable may still
possibly deceive us (this is the problem of induction). Also, we must consider the possibility of the
application of the method - after all, human beings are not perfect and even a reliable method does
not stop people making mistakes.
4. Conclusive Reasons. The main objection to this theory is that it tends to exclude a lot of things that
we would consider knowledge. In other words, true knowledge would be quite rare if we only ever
accepted it when there were conclusive reasons. As we have already seen, knowledge which
excludes all doubt tends to tell us nothing about the world (e.g. all bachelors are unmarried). On
the other hand, knowledge which gives us information about the world (e.g. all bachelors collect
stamps) is always open to doubt. This leaves us with the problem of defining what exactly a
conclusive reason might be.
5. Causal Connection. The final theory proposes that there must be a direct link between my
justification (seeing Sam) and my belief (Sam is in the room). Therefore, Gettier is answered by
arguing that my belief that Sam is in the room is false when it is Tim that I see, but it would be true
if it were Sam.
There are a number of problems with this view, but the most convincing of them involves
inductive arguments. Consider an argument such as "all humans are mortal". What is the cause of
this belief? If it is the fact that individuals die, then this cannot be said to cause the belief that all
people die (so there appears to be no direct link between the facts and the belief). On the other
hand, the fact that humans die – because it is an inductive argument – cannot be known by me.
However, would we really say that we do not know that “all humans are mortal”? This seems too
strict a rule.
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Summary of Gettier Problem and Responses.
As you can see, none of the suggested solutions to the Gettier problem are without their faults. Does
this mean that all attempts to define knowledge are fruitless? Whatever the case, it appears that the
tripartite definition offered by Plato is inadequate. However, this may not be as disastrous as it sounds.
As we have seen in looking at Descartes‟ attempts at finding an absolutely indubitable truth, absolute
certainty may be beyond our reach. However, we do make claims to knowledge everyday and rely on
them to go about our daily business. So, is it that important that we cannot be absolutely certain about
anything? If this approach is taken, we may either say that there is no such thing as knowledge – which
seems a very sceptical position to take – or adopt the position that what we term knowledge may still
be open to doubt. Either way, we may adopt a pragmatic approach that allows us in our day-to-day
activities – or even our scientific endeavours – to still make claims to knowledge.
We will now go on to look at different definitions of truth.
Foundationalism
The first theory of truth we are going to look at is called Foundationalism. As the term implies, this
view assumes that certain beliefs act as a foundation for other beliefs. So, for instance, the statement,
“The car is red” is a foundational belief in that it is not based upon other beliefs, but is a direct
experience.
On the other hand, a statement such as, “The Ferrari Testerosa is the fastest road car in the world” is
not foundational in that it rests on other beliefs (such as my trust in second hand information in
magazines, my own knowledge of available cars, etc.). Such a belief is nonetheless still part of a
foundational theory of knowledge.
From this point of view, beliefs are more or less certain according to the extent to which they can be
derived from foundational beliefs. Some beliefs, such as that there is a soul which survives the death of
the body, are very difficult to prove in that they seem very far removed from direct foundational beliefs
(such as that we have a mind).
Exercise
What beliefs about the objects around you or the situation you are in are foundational, and what are
based upon such beliefs?
Correspondence Theory
Foundationalism is basically what is termed a correspondence theory of knowledge. This is because
certain beliefs held in the mind are said to correspond – or not – to states of affairs in the outside world.
States of
Beliefs Affairs
The problem with this view is that we have no way of checking our beliefs. In other words, if I believe
that the moon is made of cheese, I can check this against the state of affairs, or ask an astronaut.
However, aren‟t these ways of checking reliant upon other foundational beliefs? What do they in turn
rely upon? So, either the fundamental truth is somehow self-evident – whatever that means – or there is
a further supporting truth. And so we are caught in what is called an „infinite regress‟ – so called
because the reasons which we base our beliefs upon regress infinitely (in other words, there is never an
end to them).
As you may recall from the previous unit, the realist view of perception was open to similar criticisms.
This is because realism implies a correspondence theory of knowledge.
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Coherence theory and Idealism
From the above criticisms, it can be seen that the idea that beliefs correspond to states of affairs is
problematic. This is because what we get are not „states of affairs‟ at all, but only other perceptions that
in turn require foundations. What can they be checked against?
Idealism, which if you remember argued that our perceptions do not correspond to a separate reality,
argues that there are no foundational beliefs. Rather, our beliefs exist in a network of interrelated
perceptions. From this point of view, no one belief is more important than another, but throw light
upon one another.
There are 3 main problems with this view:
1. If false beliefs outweigh true ones, this would make the incorrect conclusion the correct
one – according to the coherence theory of truth. For instance, if I believe that the 1969
moon landings were faked in a photographic studio, I might be able to back this up with
selective evidence. If I then reach a point where the evidence for this is more than for the
belief that the moon landings took place, I would be forced to conclude that it was the
truth.
2. Coherence theory is also circular. If a certain belief is true because it coheres with others,
what do they cohere with? This is another example of an infinite regress. Also, since
coherence theory is not a foundational theory, we cannot appeal to one or a select number
of beliefs over the others, because all beliefs are equal.
3. What does coherence itself consist of? If someone were to establish criteria for coherence,
this in itself would only be another belief, and so subject to the same criticisms, wouldn‟t
it?
Reliabilism
A further account of knowledge and truth is provided by reliabilism. This theory supposes that our
main method of justifying our beliefs is to appeal to what has been reliable in the past. Thus, if I want
to prove to someone else that I could speak Russian (and not just some string of made-up, Russian-
sounding words), we could both go to a native Russian speaker or a lecturer in the languages
department at a university who could confirm it. I could also translate some Russian books or attempt
to display my knowledge by answering their questions.
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These methods would be acceptable to different degrees depending on how reliable they have proven
to be. For instance, the fact that I can „prove‟ to a large group of people that I can make a coin
disappear is not very reliable (a fact that stage magicians exploit).
There are two main methods of reliabilist justification: internal and external. External is obviously the
most reliable because it deals with what is apparent to others. So, if I wish to establish some medical
fact, I can visit a doctor, who has established scientific ways and means of confirming a diagnosis.
Alternatively, I can rely on my own internal sensations to inform me of my own condition (which is
obviously not so reliable or open to demonstration).
Problems with Reliabilism
The internalist form of reliabilism seems to be circular. How do we know that the methods we use to
establish that something is true are really reliable? What method do I use to check that the means for
establishing whether the reliable method is reliable is itself reliable? And so on.
The externalist form is open to the criticism that just because a method – such as use of a thermometer
- gives us a reliable response, this does not mean that the response is true. So, a computer with a bug in
it might always provide the same response to a particular question, but that would not be the correct
one.
Discussion
Can you think of any other criticisms of reliabilism? Is it better as a theory of truth than the others
already discussed? Are there any counter arguments that a reliabilist could use?
Phenomenalism
The last theory we are going to look at is Phenomenalism. We looked briefly at this in the last unit and,
as you may recall, the theory proposes that we cannot experience anything beyond the phenomena of
our perceptions. This view, similar to Idealism, states that the real objects of experience are beyond us,
and that we cannot experience them directly.
The most well known form of Phenomenalism is that proposed by the English philosopher A. J. Ayer
and the movement known as Logical Positivism. From Ayer‟s viewpoint, a proposition is true only if
some experience can verify it. So, the statement that the Amazon is the longest river in the world may
be measured by looking at satellite photographs of all the world‟s rivers. However, the statement that “I
can turn invisible but only when I close my eyes, no one is looking and there are no cameras, etc.” is
considered by Ayer to be nonsense because there is no possible way that anyone – even the „invisible
man‟ himself – can verify it. This is called the Verification Principle.
For Phenomenalists, all statements about the world are actually statements about sense experience –
whether actual or possible. So, although we may not currently be able to prove that there has been life
on Mars, it may in future be possible to do so. In this sense, whereas Idealists considered material
objects not to exist, Phenomenalists consider them „permanent possibilities of experience‟.
Problems with Phenomenalism
Phenomenalism as a theory of truth is a form of reliabilism. What can be justified – or verified – has
meaning, what cannot be – at least potentially - is nonsense. The methods used to verify statements are
traditional empirical and scientific ones – i.e. the senses plus scientific equipment. As such, it is open to
some of the same criticisms as reliabilism itself.
However, perhaps the main problem with the approach is that the verification principle itself is too
vague. How is a statement verified?
Maths and logic are also problematic for this theory in that they are truths that seem to be independent
of sensory verification. Ayer‟s answer to this was to consider them conventions of language. Similarly,
all ethical and aesthetic statements were held to be neither true nor false because they could not be
verified.
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Ironically, one criticism points out that the verification principle itself is not – by its own criteria -
meaningful. For, it is not an analytic truth (a „convention of language‟) and neither is there any possible
or actual sense experience that could be said to verify it.
Summary
This unit has looked at various approaches to the definition of knowledge and truth. It has also
distinguished between two types of knowledge – by acquaintance and by description – and
distinguished between knowledge and belief. We also looked at the tripartite definition of knowledge
introduced by Plato, considered objections to this – so-called Gettier problems – and then critically
examined attempted solutions. We then looked at Foundationalism and considered the Correspondence
theory of truth which it implied. Problems with this lead us to look at Idealism and the Coherence
theory of truth. Finally, we looked at Phenomenalism and the Reliabilist theory of truth.
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This ends the Theory of Knowledge module of AS Philosophy. Before moving on to the next module,
complete the following assignment.
Assignment 5: Unit 4 - Definition of Knowledge
Answer the following past paper question below (answer all parts). The deadline for submission is the
week ending December 6th 2002. Essays may be handwritten or typed. Submissions may be via email,
post or in person. You may also upload a Word file by clicking on the button below. There is an upper
word limit of 2000 words, and a lower limit of 600.
Total 45marks.
1. Identify and illustrate two ways in which beliefs may be justified. (6 marks)
2. Outline and illustrate the role of justification in distinguishing between knowledge and true belief.
(15 marks)
3. Assess the view that knowledge is true justified belief. (24 marks)
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