The Existence Predicate in Fregean Logic

One of the most basic doctrines in the predicate logic is that existence can never be a predicate; rather, it is the particular quantifier. Here Ill try to explore the views of the founders of Fregean logic on the structure of the proposition, and why it does not take existence as a predicate. Then Ill state their explanation and solution for existential propositions. Finally, Ill investigate the shortcomings of their analysis. Many analytical philosophers, including Moore, Kneale, Wisdon, Ayer, etc, who have denied 'existence' as a predicate, have done so as part of their refutation of the ontological argument for the God's existence. However, here Ill deal only with Frege, Russell, and Quine. The other philosopher's stance can more or less be found in one of these three.