LANGUAGE introduces a distinction between the reference of an expression (the object to which it refers, as the planet Venus is the reference of ‘the morning star’) and the sense of an expression (the particular mode in which a sign presents what it designates) ‘The evening star’ differs in sense from ‘the morning star’ even though it has been discovered that both expressions refer to Venus Frege says, in general, that an identity statement will be true and informative if the sign of identity is flanked by two names with the same reference but different senses The word ‘name’ is, as the example shows, used by Frege in a broad sense to include complex designations of objects He is prepared to call all such designations ‘proper names’ (CP 157–8) Frege applies the distinction between sense and reference to sentences of all kinds In his account of meaning there are items at three levels: signs, their senses, and their references By using signs we express a sense and denote a reference (CP 161) In a well-regulated language, Frege believed, every sign would have a sense and only one sense In natural languages words like ‘bank’ and ‘port’ are ambiguous, and a name like ‘Aristotle’ can be paraphrased in many different ways; we have to be content if the same word has the same sense in the same context On the other hand, there is no requirement, even in an ideal language, that every sense should have only one sign The same sense may be expressed by different signs in different languages or even in the same language In a good translation, the sense of the original text is preserved What is lost in translation is what Frege calls ‘the colour’ of the text Colour is important for poetry but not for logic; it is not objective in the way that sense is The sense of a word is what we grasp when we understand the word It is quite different from a mental image, even though, if a sign refers to a tangible object, I may well have a mental image associated with it Images are subjective and vary from person to person; an image is my image or your image The sense of a sign, on the other hand, is something that is the common property of all users of the language It is because senses are public in this way that thoughts can be passed on from one generation to another For Frege, it is not only proper names—simple or complex—that have senses and references What of entire sentences, which express thoughts? Is the thought, that is to say the content of the sentence, its sense or its reference? 122