In the actual practice of philosophy we are constantly faced with such questions as ‘ Does know, or believe, or aware, or deception (in self-deception and deception of another), or good, or right, or ought, or necessary, or if, or because, or reason, or cause or. . .have one or more than one sense?’ If we were not faced with the practical necessity to decide such questions we should probably be well advised to delay considering them, if only because, so far as I am competent to judge - which I hardly am at all, but this is my tentative opinion - the practice and whole methodology of the relevant parts of linguistics are at present in too provisional and uncertain a state of development. But we cannot always delay, and there may be something to be said for doing what I shall do in any case. This is to make one final assault on the problem of sentence-sense, word-sense and difference of word-sense, from within the traditional theory of meaning -if only to commemorate the achievements (mainly Aristotle’s and Frege’s) of an activity perhaps even more certainly doomed to extinction than everything else which is familiar to us. Before the existing assets of this part of philosophy are transferred and vested in a renascent science of linguistics or in a new branch of model theory, it may perhaps help to get them redeployed usefully if they are identified and accurately accounted for.

Even with the antique apparatus at the disposal of the philosophical theory of meaning it is possible, I think, to show that when people have asked ‘ Does word w have more than one sense? ’ at least three sorts of question have been at issue. They are:

1. Does the word type w have more than one lexical content?
2. Does the word type w in different contexts represent more than one kind of proposition-factor or paraphrase-component?
3. Where the answer to (i) is yes, do we really have to suppose that w is a mere homonym?

For reasons which will become evident I should call the first an input question, the second an output question, and the third a question about the relationship between different inputs. All these terms will be explained in due course. I shall first try to show that the proper concern of a dictionary is question (i), and that the notion of lexical content is the most useful interpretation of the notion of sense or Sinn. Question (ii) really pertains to the problem of property-identity, not the problem of difference of meaning. But before I can show anything about words I must say something about the sense or meaning of sentences.

¹ This is a revision of the opening address given to the Oberlin Philosophy Colloquium in 1968. The commentator was William Alston and the original title was ‘ How does one tell if a word has one, several or many senses?’ At some points the notes stray some distance from the contentions of the text and may usefully be omitted.