The Philosophy Resource

Teaching resources for philosophy students and teachers

What is epistemology?

‘Epistemology’ the word, is derived from the Greek word ‘episteme’, meaning knowledge. Epistemologists are philosophers who are trying to understand what knowledge is. The central question that occupies them is: what is knowledge?

Different kinds of knowledge

Traditionally, epistemologists have been most interested in what is called propositional knowledge, as opposed to practical knowledge.

Propositional knowledge is the kind of knowledge we attribute to people when we say things like: ‘James knows that Paris is the Capital of France’ (a proposition can be understood, roughly, as a statement which can be true or false. In this example the proposition is ‘Paris is the capital of France’. Some other random examples of propositions are: ‘All men are mortal’; ‘water is H2O’ and ‘Manchester United won the league last year’).

Practical knowledge is the kind of knowledge we attribute to people when we say things like ‘Sophie knows how to ride a bike’. Sentences concerning propositional knowledge have propositions as their object; sentences concerning practical knowledge have skills or abilities as their object.

Propositional knowledge = Knowledge That
Practical knowledge = Knowledge How

In recent years, epistemologists have shown an increasing interest in understanding knowledge how; on whether propositional knowledge and practical knowledge are completely different kinds of knowledge – that is, on whether practical knowledge is really a form of propositional knowledge or vice-versa. However, here we’re going to focus on propositional knowledge only.

What is propositional knowledge?

Another way of putting the question is: what must be true of a person such that she can accurately be described as knowing a proposition. To make things a bit neater, we can formulate the question like this:

Question: What must be true of S (a subject, a person) such that she can accurately be described as knowing that p (a proposition)?

Perhaps the most immediate answer is to say that in order for S to know that p it is necessary that S’s belief that p be true. James does not know that London is the capital of France. Why? Because the proposition ‘London is the capital of France’ is not true. Sophie does not know that Bill Gates founded Apple. Why? Because the proposition ‘Bill Gates founded Apple’ is not true. We can express this as follows:

S knows that p if:

  1. S believes that p.
  2. P is true.

Let’s start the analysis

What we want out of our analysis of knowledge (our answer to the question: what is knowledge?) is that it picks out cases of knowledge as knowledge and cases of non-knowledge as non-knowledge. In other words we want the definition to be both necessary – that is, specify what knowledge has to be – and sufficient – that is, specify what circumstances would be enough for us to say knowledge was definitely present Is the above definition (1) & (2) a sufficient definition of knowledge, however? Put differently, can something be a case of non-knowledge and yet, under the definition, qualify as knowledge? Unfortunately for (1) & (2) the answer seems to be ‘no’.

Suppose James believes that he owns a Nintendo 3DS. He believes it because last night he dreamt that he owned one. Suppose that by chance James’ kindly uncle Buck surprisingly came into town and secretly placed a Nintendo 3DS among James’ possessions, such that the proposition ‘James owns a Nintendo 3DS’ is true. So James believes that he owns a 3DS and it is true that he owns one, so he satisfies conditions (1) & (2). Still it seems wrong to say that he knows that he owns a 3DS in this case. So satisfying (1)& (2), though necessary for knowledge – that, is knowledge has to satisfy (1) & (2) to count as such – is not sufficient for knowledge; that is, (1) & (2) are not enough to give us knowledge. It seems that James was just too lucky that his belief turned out to be true. The lesson we might draw from this is, then, that knowledge and luck are incompatible. We must address this in our account of knowledge. We might do this by introducing a new condition on knowledge, meant to eliminate the possibility of our knowing luckily:

S knows that p if:

  1. S believes that p.
  2. P is true.
  3. S is justified in believing that p.

Because there are three conditions in the above account, it is sometimes called the tripartite analysis of knowledge. It is an old account of knowledge and goes back to Plato’s Theaetetus. The idea is that it is not enough for our beliefs to be true in order to qualify as cases of knowledge, they must also be arrived at for the right reasons – they must be justified.

Going forward, we will address some objections to the tripartite analysis and will look at the prospects of modern epistemology in light of them.

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