rationalskepticism.org

ughaibu wrote:

jamest wrote:existence cannot be defined... by logical default.

If we need to talk about existence, then we need to be clear about what we mean by the term. But this is true of many terms, and the problems of producing a fully consistent and satisfactory definition exist, at least equally, for "truth" and "knowledge". Of course, we can say what we mean by those terms too, if our meaning needs to be made precise.
By the way, in my second sentence, "exist" means can be clearly stated and understood.