Einführung in die Theoretische Philosophie: Sprachphilosophie

1. Einführung in die Theoretische Philosophie: Sprachphilosophie Nathan Wildman nathan.wildman@uni-hamburg.de

2. More about Frege’sPhilosophy of Language Extending Frege’s story from singular terms!

3. ‘Bucephalus is a horse’ Bucephalus is a horse What does this sentence mean? Breaks down into two questions: • What does ‘Bucephalus’ mean? • What does ‘is a horse’ mean?

4. Dilemma about Identity Frege’s opening question: ‘Equality gives rise to challenging questions which are not altogether easy to answer. Is it a relation? A relation between objects, or between names or signs of objects?’ When we express ‘Hesperus is Phosphorus’ using the ‘is’ of identity, ought we to write it as (1) Hesperus = Phosphorus (2) ‘Hesperus’ = ‘Phosphorus’

5. Identity as a Relation between Things Frege points out the following: ‘a=a and a=b are obviously statements of differing cognitive value; a=a holds a priori and, according to Kant, is to be labelled analytic, while statements of the form a=b often contain very valuable extensions of our knowledge and cannot always be established a priori.’ a=a is analytic, a priori, of negligible cognitive value a=b is synthetic, a posteriori, of high cognitive value

6. Identity as a Relation between Things Frege now objects: ‘Now if we were to regard identity as a relation between that which the names ‘a’ and ‘b’ designate, it would seem that a=b could not differ from a=a.’ Relevantly, the two expressions could not differ in cognitive value!

7. Identity as a Relation between Things The argument (P1) Given the Naive Theory, if identity is a relation between objects, ‘a=a’ and ‘a=b’ must have the same meaning. (P2) If two expressions mean the same thing, they do not differ in cognitive value. (P3) ‘a=a’ and ‘a=b’ differ in cognitive value. (4) ‘a=a’ and ‘a=b’ do not mean the same thing. ∴ (C1): Identity is not a relation between objects.

8. Identity as a Relation between Names So on to the second option, where ‘Hesperus is Phosphorus’ should be written as (2) ‘Hesperus’ = ‘Phosphorus’ Of course, not this (as it is obviously false), but really (3) The terms ‘Hesperus’ and ‘Phosphorus’ designate the same thing. This is the Metalinguistic Thesis.

9. Identity as a Relation between Names (P1) If identity is a relation between names, then what we learn from identity statements is that two terms designate the same thing (P2) If what term we use to designate an object is arbitrary, then learning that two terms designate the same thing does not give us proper knowledge (P3) What term we use to designate an object is arbitrary (4) Learning that two terms designate the same thing does not give us proper knowledge

10. Identity as a Relation between Names (5) If identity is a relation between names, then identity statements do not give us proper knowledge (P6) Identity statements do give us proper knowledge about the world ∴ (C2) Identity is not a relation between names.

11. Dilemma about Identity Frege’s Puzzle: Identity cannot be a relation between objects, nor can it be a relation between names. But clearly identity is a relation between something! So what should we do? Frege’s Answer: Reject the Naive Theory & the claim that the meaning of a singular term is nothing but thereferent.

12. Solution to the Problem Frege: ‘A difference can arise only if the difference between the signs corresponds to a difference in the mode of presentation of that which is designated.’ In other words: Find some element which captures the mode of presentation of an object via the employed singular term

13. A Short Adventure Explorer 1 (call him ‘Marco’), traveling in an unexplored area, sees a snow-capped mountain on the northern horizon.

14. A Short Adventure • Talking to natives, Marco learns it is called ‘Aphla’. • Sighting different points, Marco enters it onto a map of the area. • Measuring, he writes ‘Aphla is at least 5000 metres high.’

15. A Short Adventure Explorer 2 (call him ‘Christopher’) sees a snow-capped mountain on the southern horizon.

16. A Short Adventure • Speaking to a few natives, Christopher learns that it is called ‘Ateb’. • Sighting different points, he enters it into a map of the area. • Measuring, he writes ‘Ateb is at least 5000 metres high.’

17. A Short Adventure • People go on using Marco & Christopher’s maps for several years, navigating around this distant land wonderfully. • Over a few drinks at the Explorers Club, Marco and Christopher meet up & discuss their respective discoveries. Gradually, they come to realize that they saw the same mountain. • At this point, they agree that ‘Ateb is Aphla’ • This proposition is a ‘valuable piece of geographic knowledge’.

18. A Short Adventure If all there was to the name ‘Aphla’ was the reference – the mountain itself – then • Aphla is Aphla • Ateb is Aphla would express the same thought. But then how could Christopher & Marco have gained any geographic knowledge?

19. A Short Adventure Problem: these two expressions differ in cognitive value – they express different thoughts– but they have the same reference. So what corresponds to the name ‘Ateb’ as part of the thought must therefore be different from what corresponds to ‘Aphla’ • Can’t be their reference, because that is the same • Frege’s answer: must be the senses!

20. A Short Adventure Thus Frege: ‘…I say accordingly that the sense of the name ‘Ateb’ is different from the sense of the name ‘Aphla’.’ Further, ‘An object can be determined in different ways, and every one of those ways of determining it can give rise to a special name, and these different names then have different senses; for it is not self-evident that it is the same object which is being determined in different ways.’ [Frege, LtJ]

21. A Short Adventure Once we have sense, we can explain why the thoughts • Ateb is at least 5000 metres high • Aphla is at least 5000 metres high are different: they contain parts which have different senses. So the sense of the complex expression is itself different because the senses of the parts are different – even though the truth-conditions are the same!

22. A Short Adventure The sense of a singular term can’t be subjective, however. • If it were, the sense of the thought in which the sense of a name occurs would then be subjective as well. So, e.g. ‘Ateb is at least 5000 metres high’ would be subjective. If this was subjective, the thought one man connects with the expression would be different from the thought another man connects with it

23. A Short Adventure That’s bad – then, ‘a common store of thoughts, a common science’ would be impossible. Thus Frege: ‘It would be impossible for something one man said to contradict what another man said, because the two would not express the same thought at all, but each his own.’ [LtJ]

24. Making Sense of it all Frege’s suggestion: ‘It is natural, now, to think of there being connected with a sign (name, combination of words, letter), besides that to which the sign refers, which may be called the reference of the sign, also what I should like to call the sense of the sign, wherein the mode of presentation is contained. ... The reference of ‘Hesperus’ would be the same as that of ‘Phosphorus’, but not the sense’ (OS&R)

25. Making Sense of it all Senses for Singular Terms In the case of a=b • Singular Terms a and b each have a sense and a referent; the sense of a isdifferent from the sense of b, though the referent of a is the same as the referent of b. • The difference in sense explains how a = a and a = b can differ in cognitive value (or meaning) even when a = b is true.

26. Frege’s story for singular G-units ‘50 Cent’ DENOTES EXPRESSES Sense of ‘50 Cent’ DETERMINES

27. Frege’s story for singular G-units ‘Curtis Jackson’ DENOTES EXPRESSES Sense of ‘Curtis Jackson’ DETERMINES

28. Frege’s story for singular terms ‘Curtis ‘50 Cent’ Jackson’ EXPRESSES EXPRESSES DETERMINES Sense of ‘50 Cent’ DETERMINES Sense of ‘CJ’

29. What to do with The Dude? What about singular terms that fail to refer? The Dude, unfortunately, is just a fictional character – he does not really exist.

30. What to do with The Dude? ‘The Dude’ DENOTES EXPRESSES Sense of ‘The Dude’ DETERMINES

31. Frege on non-referring singular terms Thus both things seem to me necessary: (1) the reference of a name, which is that about which something is being said, and (2) the sense of name, which is part of the thought. Without reference, we could indeed have a thought, but only a mythological or literary thought, not a thought that could further scientific knowledge. Without a sense, we would have no thought, and hence also nothing that we could recognize as true. [Frege, LtJ]

32. Frege on non-referring singular terms …this is not to say that to the sense there also corresponds a reference. The words ‘the celestial body most distant from the Earth’ have a sense, but it is very doubtful they also have a reference. The expression ‘the least rapidly convergent series’ has a sense; but it is known to have no reference… In grasping a sense, one is not certainly assured of a reference.’ [OS&R]

33. singular terms with unknown reference Frege: The sense of a proper name is grasped by everybody who is sufficiently familiar with the language or totality of designations to which it belongs; but this serves to illuminate only a single aspect of the reference, supposing it to have one. Comprehensive knowledge of the reference would require us to be able to say immediately whether any given sense belongs to it. To such knowledge we never attain. [OS&R]

34. singular terms with unknown reference ‘The Tallest Person in the room’ DENOTES EXPRESSES Sense of 'The Tallest Person in the room’ ???? DETERMINES

35. Sensible Lessons (1) Each meaningful singular term has a determinate sense (‘Sinn’) and (at most) a single referent (‘Bedeutung’) • No sense, not meaningful • No referent, then either (a) not a singular term (no single referent) (b) a non-referring name (no referent at all)

36. Sensible Lessons (2) The referent of a singular term is the ‘definite object’ that it stands for. (3) The sense of a singular term contains a “mode of presentation” and is what determines the term’s referent (if any). (4) Sense ≠ idea (‘Vorstellung’) • Telescope analogy • Subjectivity point above

37. Sensible Lessons (5) Some theoretical work for sense: (a) Someone who understandsa singular term knows the sense of the term (b) Two singular terms s and s’ in L are synonyms in L iff the sense of s in L = the sense of s’ in L (similar criterion for translation across languages!) (c) A singular term is ambiguous in L iff more than one sense is associated with it

38. Frege on Predicates Predicates express senses and denote concepts (like singular terms, just different denotation) Concepts are unsaturated – they need objects to instantiate them in order to exist. • Think of a concept like a donut hole A concept cannot exist without an object saturating it.

39. Frege’s story for predicates! The story centres on a circular animal-like creature that is missing a wedge-shaped piece of itself. It doesn’t like this, and sets out to find its missing piece, singing: Oh, I'm lookin' for my missin' pieceI'm lookin' for my missin' pieceHi-dee-ho, here I golookin' for my missin' piece

40. Frege’s story for predicates! Concepts are like the circle that’s missing a piece – something central to what they are is absent when they are unsaturated. Only by being saturated by an object is a concept completely whole. Importantly, predicates express senses and denote concepts (like singular terms, just different denotation)

41. ‘Bucephalus is a horse’ Bucephalus is a horse What does this sentence mean? • What does ‘Bucephalus’ mean? • Determined/constituted by the sense of ‘Bucephalus’ • What does ‘is a horse’ mean? • Determined/constituted by the sense of ‘is a horse’

42. A sense for sentences The sense of a complete declarative sentence is a thought (‘Gedanke’) ‘By a thought I understand not the subjective performance of thinking but its objective content, which is capable of being the common property of several thinkers.’ (Frege, OS&R, footnote 7) • What makes up the thought of a sentence?

43. A sense for sentences Answer: the senses of the constituent expressions! (Psst! - Remember Compositionality: The meaning of a complex expression depends on the meaning and arrangement of its constituent parts?) The thought of the sentence ‘Bucephalus is a horse’ is composed of the senses of ‘Bucephalus’ and ‘is a horse’

44. A sense for sentences Sentence Bucephalus is a horse Thought {[Bucephalus] + [is a horse]} Reference ??????????

45. A Reference for Sentences (1) Frege endorses a compositionality thesis about reference: the reference of a complex expression is determined by the references of its constituent expressions. (2) So reference of a sentence is determined by reference and structure of its constituent expressions. (3) But two sentences whose expressions are all co- referential (and arranged in the same way) can express different thoughts. (4) So the reference of a sentence  thought it expresses

46. A Reference for Sentences (5) We care about reference of constituent expressions of a sentence just when we care about truth value of sentence: “It is striving for truth that drives us always to advance from the sense to the referent”. (C) ‘We are therefore driven into accepting the truth value of a sentence as its referent’. The reference of a sentence is its truth-value

47. A Reference for Sentences There are two truth values TrueFalse Every sentence that has a referent refers to one of these We are therefore driven into accepting the truth value of a sentence as constituting its reference. By the truth value of a sentence I understand the circumstance that it is true or false. There are no further truth values. For brevity I call the one the True, the other the False. Every declarative sentence concerned with the reference of its words is therefore to be regarded as a proper name, and its reference, if it has one, is either the True or the False. [OS&R, emphasis mine]

48. A Reference for Sentences Three comments • This means that Truth Values are objects, just like people, tables, chairs, etc. • Sentences are just really complex singular terms, picking out truth values • The difference in cognitive value between two sentences must be explained by difference in thought (since they might have the same referent)

49. A Reference for Sentences Sentence Bucephalus is a horse Thought {[Bucephalus] + [is a horse]} Reference The True

50. A Reference for Sentences Sentence Prince is a horse Thought {[ ] + [is a horse]} Reference The False