Thursday, March 31, 2011

Frege's distinction between sense and reference

To: Joao T.
From: Geoffrey Klempner
Subject: Frege's distinction between sense and reference
Date: 14 June 2001 12:13

Dear Joao,

Thank you for your e-mail of 4 June, with your essay for units 7-9 of the Philosophy of Language program, in response to the question, 'What is the point of Frege's distinction between sense and reference?'

The key question for Frege is how there can be something *objective* that accounts for the route to reference.

That is why Frege would reject the account which allows that the sun for Joao is the same object as the sun for Geoffrey, but Joao and Geoffrey have different 'private data' of the sun. The mode of presentation of the reference, the sun, is the same for Joao as it would be for anyone in Joao's geographical location, just as the mode of presentation of the sun for Geoffrey is the same as it would be for anyone in Geoffrey's geographical location. An account of the workings of language is not concerned with 'private data'.

However, I wonder whether in fact your example, 'Joao says that the Brazilian sun is brighter than the English one', is best analyzed as a case of Fregean 'indirect reference'.

Let's consider Frege's own example, Hesperus and Phosphorus (the Evening star and the Morning star). We know that 'Hesperus' and 'Phosphorus' both refer to the planet Venus. But let us suppose that Joao believes that Hesperus and Phosphorus are two different planets. And let us also suppose that Joao also believes that Hesperus is in a closer orbit to the Earth than Phosphorus. In reporting Joao's statement of his belief, I would say, 'Joao says that Hesperus is in a closer orbit than Phosphorus'. What matters, for the truth value of this statement involving indirect reference, is not the reference of 'Hesperus' and 'Phosphorus', which is the same, but the sense of the terms 'Hesperus' and 'Phosphorus'. We can preserve the truth value of that statement by substituting terms with the same sense - 'Evening star' for 'Hesperus', 'Morning star' for 'Phosphorus' - but not if we substitute terms with the same reference.

Now it is possible that someone, a child say, might believe that the sun which they saw in Brazil is a different heavenly body from the sun which they saw when they came to England for a holiday. This would be just like the example of Hesperus and Phosphorus. The child believes that the Brazil sun is a brighter sun than the English sun. There are two suns, and one is brighter than the other. However, when you, Joao, say, 'The Brazilian sun is brighter than the English one' you don't mean this. What you mean is simply that The sun *appears* brighter in Brazil than it appears in England!

It is important to note that in order to use the sense/reference theory to explain the truth conditions for statements involving indirect reference, 'Joao believes that....', 'Joao says that...' etc. we need first to be convinced that there *is* such a thing as a 'sense'. As Frege was aware, we need independent reasons for accepting the sense/ reference distinction before we can be confident in putting it to work in accounting for indirect reference. That is why, in his essay 'On Sense and Reference', Frege first tries to motivate the distinction by describing the problem of identity statements.

One interesting thing that follows from Frege's account is that we cannot rely on finding any linguistic formula that would fully capture the sense of a term. It is not true in every case that sense 'can be told but can't be touched'. Sometimes sense can neither be told not touched.

Here's one example: Your guide takes you to a hunting lodge hidden deep in the forest. He tells you that the hunting lodge is called 'Austerlitz'. After a few visits to the lodge, you learn to find it for yourself. Then one day your guide takes you to another hunting lodge which is reached by entering a different part of the forest. This lodge is called 'Waterloo'. Again, after a few visits you learn to find the lodge for yourself. You notice that there is a great similarity between the two lodges, and in the parts of the forest in which they are located. Then one day you discover a box of ammunition in the Waterloo lodge which you had put away in a cupboard in the Austerlitz lodge. 'Its the same lodge! I didn't realize. Waterloo is Austerlitz!'

What is important in this example is that the senses of the terms 'Austerlitz', 'Waterloo' are not associated with *any* verbal description. This contrasts with the case of Hesperus and Phosphorus, which are associated with the verbal descriptions, 'the first star to appear in the evening', 'the last star to disappear at dawn'. The sense or 'route to reference' of the term 'Austerlitz' is associated with a practical ability, the ability to find the hut in the forest, and similarly for the sense or 'route to reference' of the term 'Waterloo'.

This example best shows the contrast between Frege's theory of sense and reference and Russell's 'description' theory.

All the best,

Geoffrey