 Note, however, that one could in principle retain their analysis and deny, for example, that first-level concepts and propositional functions, respectively, can only be saturated by objects that exist. One could take the view that some great philosophers who once existed, no longer exist. Socrates, for example, was a great philosopher who no longer exists. He can nevertheless instantiate the first-level concept admired by many philosophers. Or consider the bookcase I would have built, had I finally assembled all the materials I purchased according to the assembly instructions that came with them. I have had concrete plans to build the bookcase for ages now; never mind the fact that I may never find the skill, time or energy to assemble it. My planned bookcase does not exist yet, and knowing myself, it might well never exist. But one might take the view that we can refer to it and that it instantiates many first-level concepts such as being a planned bookcase. On a view like this, the assertion that there are planned bookcases that do not exist would remain true even if none of its instances exist.