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What are the Bearers of Truth Values?

In a discussion of what the bearers of truth values are, and more specifically which of sentences, statements and propositions bear truth, it is obviously going to be fairly important to correctly define your terms, so that the differences between these three things, which at first might seem very similar indeed, is clear. This is not necessarily a simple task, since these things are, indeed, very much related, and there is some debate about exactly how we shall characterise these three things - whilst it is possible the following are not the least controversial definitions, I hope they are most useful for logicians and linguists alike.

Sentences can be described simply as any set of words placed together in a grammatical structure - that is any set of words that appear (on the surface, at least) to be doing more than just making some noise. An obvious consequence of this is that a sentence in one language will not be a sentence in another language, simply by translating the words, but rather a rearrangement in line with the grammatical structure of the second language must be performed before we may say the set of words is a sentence in the new language.

Statements are the things that are being put forward when what Haack calls a 'declarative' sentence is uttered or written down. A declarative sentence is one that is trying to 'say' something - i.e. one that uses the indicative mood rather than the interrogative, which asks if something is so, or the imperative, which tells someone to do something. For logicians sentences in the subjunctive mood, also, should be included, as to say something 'might' happen is certainly a very important statement about the world or possible worlds. Sentences in other moods can even be converted to ones which make statements. For example Frege suggests that to say 'Yes' to a sentence in the interrogative is as much as to say that there is a statement hidden within, and that you feel it is true. Another important qualification that Frege makes is that to have people assign a value of true or false to a statement, it must be serious, and the speaker must mean it. Therefore it does not really make sense to say that what someone says on stage or in poetry, for example, isn't 'true' because they are not actually making a statement, as such, merely saying a sentence as laid out in their lines. This does not, of course, prevent us from talking about what a playwright or poet was trying to say, but in doing this we are not discussing what statement an 'actor' is making with his line, or what the statements are behind a particular metaphor in a poem, but merely the statements that they themselves are trying to make.

In 'saying' something, what is happening is that a statement made in a sentence contains one or more propositions. The difference between a proposition and a statement is that propositions are that which is meant by any sentences with the same meaning, whereas a statement will be a particular arrangement of a particular set of propositions. It might be held, therefore, that most propositions on their own should be pretty much accepted before we start making statements about them, and what statements do is claim to make a connection between various different propositions, that we already know to be true or not.

So, for example, the sentence 'Elizabeth II is the Queen of England' is a sentence which contains both a statement, and propositions. The difference between statements and propositions might therefore be shown by the suggestion that the statement is not merely that 'Elizabeth II is the Queen of England' but that 'Elizabeth II is the Queen of England now in the year 1999 on the planet Earth orbiting the star 'Sol''. The reason for the additional information is that with a statement often there is extra implied conditions, which it is assumed a listener or reader will add in. The truth of the proposition, therefore, that 'Elizabeth II is the Queen of England' is obviously variable, since the same proposition set into a sentence or statement a hundred years ago would be false. Likewise (and more usefully to a philosopher) propositions of the type 'All bachelors are not and have never been married' should not vary its truth, since there can be no additional pieces of information that could make this analytic proposition false. I hope to show, however, that the reason this particular proposition has a constant truth-value is because it is exactly aligned with a statement in the same form 'All bachelors are not and have never been married', since there are no additional implied pieces of information.

I would suggest, therefore, that it is statements that are the bearers of truth. Whilst we do allow propositions to have truth values, since these need not remain constant it is clearly not going to get us very far only talking about the truth or falsehood of propositions. In fact, Strawson even goes so far as to state that 'the meaning of a statement-making sentence' explains when it would be true or false; i.e. what a statement means refers to when it is true. The use of statements, therefore, is to connect propositions to particular situations where it is suggested that the propositions are either true or false, thus a statement such as 'Elizabeth II is Queen of England' is implicitly attempting to connect a proposition which is far more often false than true with a particular moment in time (i.e. today) and a particular position in space (i.e. the Earth), and thus form a true 'statement'. Therefore to say that something is a true statement is far more useful than the acknowledging that a given proposition is often true and often false, and in the case of propositions that are always true, their associated statements are very likely to be identical.

Also Frege suggests that other things, such as pictures, could be claimed to have truth values, since (at least in part) people have been known to say that a picture is 'true'. Frege explains that to say a picture is true is to say that it corresponds correctly to the real world, and that it does describe that which it is putting across. Obviously photo-likeness is not necessary, and the reason for this could be argued to be the fact that for a picture to be true only the statements that it makes need be correct, and not every sentence; that is to say if the picture tries to convey something - the essential feeling evoked by a place, or (in the example of a map, for instance) where things lie in relation to each other - and it does so it is 'true', without needing to resemble so closely what it represents that you would not be able to tell you were looking at a picture rather than the real thing. Obviously the boundaries are not going to be as fixed, but it should be clear that Frege's argument is fairly convincing, and whilst it will be a lot more difficult to say if something other than that which is conveyed in language is correct, there are other ways to portray truths.

It should be made absolutely clear that sentences are able to make a wide variety of differing statements in different contexts. An often used example is that of someone saying something about either someone else or themselves. To say, for example, 'You are Elizabeth II' is obviously only going to make a true statement in the case where the speaker is talking to the Elizabeth II, and exactly the same sentence spoken to anybody else will in fact be false. Also it should be noted that the same proposition would be put forward in Elizabeth II saying 'I am Elizabeth II', so it should be clear that context is everything.

I would suggest, therefore, that this is where the implicitly suggested additions must come in - that we adapt in our mind the sentence that has been made so that the statement is much more specific than that which has technically been expressed. When someone says, for example, 'I am hurt' Frege would suggest that what they are actually meaning is 'he who speaks is hurt'. Frege seems to get in a little bit of a muddle, discussing the situation where someone, having been told by someone that they were hurt, choses to tell someone else. In saying 'X says they're hurt' he might not convey the same statement, since the person he was speaking to might not know X by the name X, but only by the name Mr. Y. This does, however, slightly miss the point - if the person were truly trying to express the same statement, he would merely say 'he who spoke to me is hurt', and thus there would not be any confusion as to who was hurt, since the person would be exactly specified (as the person that spoke), and whilst the exact detail of who this person was wouldn't be conveyed (in that the person the sentence was being said to wouldn't be able to recognise if it were someone they knew that was hurt) this information would surely amount to a statement with a greater scope than simply 'he who spoke is hurt'.

Haack suggests that sentence tokens are physical things, such a inscriptions on paper or sounds produced by the vibration of the vocal cords, which brings up an interesting question about whether sentences can exist in the mind. It is an interesting debate, and not one that is easily soluble, whether it is possible to think in sentences - it might at first seem more like that it is only possible to think in statements. Beliefs, for example, are likely only to be held as statements, since we think about what we think is true, not in terms of how such truths would be expressed. Frege curiously chooses to use the term 'thoughts' rather than 'statements', claiming that it will become clear why he chose to use this term as opposed to any other, and yet it seems only to get him into trouble. He concludes eventually that thoughts cannot be the bearers of truth, since they are subjective, and truth must have relevance beyond one person's 'point of view'. But this is merely a function of his choice of words, and much of his discussion about thoughts works fully if simply given a different name (e.g. statements).

He quite rightly states that the objects of thoughts often change, for example leaves on a tree going brown, thus making statements about leaves being green false, but clearly it is mistaken to say that simply because thought might take time to 'catch up', as it were, that they cannot be correct, especially if they are formulated into sentences. It must be noted, however, that one of the important claims that Frege makes is that if a change of sense is thought preserving, then it is truth preserving. This would certainly suggest that he believed that what are held in the mind are statements, and not merely sentences, thus if we change the word 'and' to 'but' in a sentence, or 'The Prime Minister' to 'Tony Blair' and we keep the same thought in our heads when we do this, then the truth values cannot have changed, since we will still be discussing the same person.

Overall, therefore, it seems that sentences are a way of putting forward statements, which are the things that are either true or false, and they gain their truth from tying together various propositions that may be true or not at varying times or places, or under a whole host of conditions. To say that a particular proposition is true may or may not get us anywhere, but the claim that a particular statement is true will help us on our way describing the way the world works and also the way various things link together.