Although we have allowed infinitely many basic categories we have, in our examples, used only two; the category 0 of sentences and the category 1 of what we have been calling 'names'. Since in Chapter Nine we shall suggest that names in ordinary language should be treated as of category (0, (0, 1> > our use of this word for symbols of category 1 is perhaps inapposite (it would be tempting and perhaps not overly misleading to call them 'logically proper names' if it were not that this phrase has acquired all sorts of unpleasant associations; when we want absolute strictness we shall speak simply of symbols of category 1). Dl under its intended interpretation is the domain of 'things'. We have already explained (p. 66) why we do not like the alternative 'individuals' (for we want to say that sets, functions, propositions and the like are all things) but we have not really said what things are.