In this context, he iterates that 'expression' as such does not refer to anything and 'sentence' as such does not have truth-value on its own. But when we 'use' in a language system they are in their functional mode. Thus, independent of their functional mode they do not possess meaning. So he confirms that we use the expression "The present king of France is bald" to refer to a particular person, and we use this sentence for making the truth or false assertion5 of it.
To use an expression is to mention or refer to a particular person or an object. In other words, expressions are used to refer to particular persons/objects. For example, "I am hungry". This sentence is used by different people and hence has different referents. Here, the word "I" has a meaning but it does not refer to anyone in particular. Its referent changes from context to context depending on the utterance of the speaker. In this regard, Strawson brings the notion called "type token sentence". For him, "type" is distinguished from "token" sentences. 'Type' is exclusively concerned with meaning, whereas uttering a sentence more than one time is called 'token'.
| 5 | Strawson, P.F. (1950). On Referring. Mind, 59, 324-325. |