The Open Question question

The Maverick has argued (in effect) that the meaning of the word 'exist' is an open question. However, if the meaning of 'exist' is what the thin theorist stipulates it is, it would not be an open question. Therefore the meaning of 'exist' is not what the thin theorist stipulates it is.

Against. It is not an open question whether 'Pegasus does not exist' means the same thing as 'There is no such thing as Pegasus'. But the meaning of 'There is no such thing as Pegasus' is not an open question. Therefore the meaning of 'Pegasus does not exist' is not an open question. Our understanding of sentences such as 'there is such a thing as x' and 'there are such things as Fs' is entirely settled, and indeed is entirely the understanding advocated by the thin theorist.

The thin theorist can also explain why some philosophers think there is an open question. For the 'thick' theorist of existence is tempted to think that the following is a valid inference,

(A) Pegasus does not exist therefore there is something that does not exist

or at least that it is an open question as to whether it is a valid inference. However it is not an open question as to whether it is a valid inference. For the inference is equivalent to

(B) There is no such thing as Pegasus therefore there is something such that there is no such thing as it

which is obviously invalid (for the antecedent is true but the consequent is false). The 'thick' theorist is tempted by the grammar of 'Pegasus does not exist' into thinking that '- does not exist' is a predicate. However, the grammar of 'There is no such thing as Pegasus' does not tempt us into thinking that 'There is no such thing as –' is a predicate. Thus there is absolutely no question about the semantics of 'exist', although its grammar tempts some people into thinking that there is.