In his book (2021) Trueman attempts to provide a solution to the problem of the concept horse, which according to Frege’s published writings is an object, not a concept. In the course of doing so Trueman rejects Wright’s response (1998) according to which some objects are also concepts, for example, the concept horse, so the categories are not exclusive. Trueman’s argument for exclusivity (Chapter 4) is the heart of the book, and as he says, it is his response to holders of differing views, like Wright. I think that there is a gap in Trueman’s argument which needs to be filled if Wright is to be considered refuted.
Frege argues that considering Socrates as an object in the proposition “Socrates exists” raises two problems. First, this proposition would be uninformative. Second, its negation entails a contradiction. Attempting to solve these problems, Frege claims that Socrates is representing the concept of a man whose name is Socrates. Therefore, existence is a second-order concept. This paper surveys the main modern theories about the types of existence, in order to find another response to Frege’s problems. For, if Socrates’ existence differs from the type that “exists” implies, “Socrates exists” is informative and its negation is not a contradiction. At last, this paper argues for an idea, in which “existence” is not a concept or property. Existence is the principle of the objects. So, “Socrates exists” is in fact “the existence is Socrates,” and “Socrates does not exist” is “there is no existence that be Socrates.” This idea could be an alternative for responding to Frege’s problems.