Defining Core Concepts..... rather making simple concepts complex!!

What is a sentence?

Utterances, propositions and sentences

Certain utterances of human languages seem to have a special status, in that they express what you might call “complete thoughts”. So if I were to say “It’s rather hot, today”, any native English speaker will interpret me as conveying a message which is somehow complete. Note that you could say exactly the same thing: “It’s rather hot, today”, which will also convey a complete message. However, if I do this on Sunday, and you do it on Monday, the message communicated is different. Linguists say that the proposition expressed is different.

A proposition is that aspect of the meaning of a sentence which allows us to say “Yes, that’s true” or “No, that’s false”. It describes a state of affairs that holds in the world, and its correspondance with that state of affairs allows us to attribute truth or falsity to the proposition. There are other aspects of sentence meaning which we will address later in the book, but propositional meaning will be the most relevant for us here. 

Note that, even though we have expressed different propositions, we have both used exactly the same linguistic form. We have both said the same sentence. This little scenario gives us some grasp on a core idea in syntax, the idea of a sentence as an abstraction over utterances which have the same form. Linguistic form is not important to a proposition. The same proposition is conveyed by the English sentence (1), the French sentence (2), and the Scottish Gaelic sentence (3), even though these sentences are in different languages:

(1) John saw Stephan

(2) Jean a vu Stephan

(3) Chunnaic Iain Stephan

So a proposition is that aspect of the meaning of a sentence which says something about a state of affairs, and an utterance is an actual use of a sentence. How do we define sentence itself then?

Take any act of linguistic communication, an utterance of (1) by me to you, for example. Somehow you glean a proposition from my utterance of (1). How do you do this? The common-sense answer is that it’s because we both know the same language. Focussing in more precisely on the question of how we define sentences, it appears that there is something about my knowledge of English which is shared with your knowledge of English, and that this includes how to form sentences of English, and how the proposition expressed by a sentence depends on its form. Clearly the form is important, since if you were to utter some sequence of sounds that did not form a sentence of English, then I’d have a much more difficult task in understanding what proposition you were trying to convey.

Part of our shared knowledge of language, then, allows us to construct sentences, which we can then utter. Again, the idea of a sentence is more abstract than the idea of an utterance (which is something that you can hear, record, feed into a computer as sound waves etc). A sentence itself is something which can’t be recorded, heard or electronically manipulated, only uses of sentences can. These stretches of words that you are now reading, delimited by capital letters and full stops and interspersed with other markings, are uses of sentences. The sentences themselves are defined by the knowledge of English that I put to use in writing them, and that you use in comprehending them. Although it sounds counterintuitive, what you see on this page are technically utterances, in that they have an external, physical manifestation. Sentences, on the other hand, are internal, mental entities, which have an abstract form.