The analysis of the predicative form of sentence was only intended as a first step in an enquiry into foundations that concerned the meaning of all linguistic expressions; and that means: the semantic forms of all sentences. Measured against this aim we have not achieved much. Firstly we have not even arrived at a general theory of singular terms nor, consequently, at a general theory of predicative sentences. The next step would be an analysis of those predicative sentences whose singular terms stand for abstract objects. Secondly, the conception thus far reached of the mode of employment of assertoric sentences would have to be widened into a general theory of all forms of assertoric sentences. And, finally, we would have to remove the restriction to assertoric sentences so as to arrive at a general theory of all sentences with propositional content.

Each of these three steps relates to a new and extensive field of investigation and in none of them, least of all in the third, can we assume that the conceptuality so far worked out can be simply transferred to the extended field of investigation. Thus in these steps the field of investigation would not simply be extended; rather each of the three steps would represent a further step in the enquiry into the foundations. In each of them one would be concerned with a reexamination of the previous conceptuality and possibly with the working out of a new, more fundamental conceptuality.

The three steps would not necessarily follow one another. The analysis of those predicative sentences in which abstract objects are referred to is not a presupposition for the analysis of the other forms of assertoric sentence; and equally the investigation of non-assertoric kinds of sentence does not have to wait until we are in possession of a complete semantics of assertoric sentences. The three steps thus do not constitute a series; rather they represent so to speak three directions in which one could continue from the stage we have now reached. This shows that this first step, even if it does not go far enough, is nevertheless fundamental for the further enquiry into the foundations.