Why did modern symbolic logic challenge the idea that existence is a property?

Modern symbolic logic challenged the idea that existence is a property by demonstrating that the surface grammatical structure of language often obscures its true logical form.1

Earlier philosophers frequently mistook the verb "to exist" for a predicate, similar to how "bite" functions in the sentence "Tigers bite." This led to the mistaken belief that existence is a property attributed to a subject. However, in symbolic logic, existence is not a property of an individual; rather, it is a higher-order function that applies to concepts.1

As the logician Gottlob Frege argued, a statement such as "Horses exist" does not attribute a property to horses. Instead, it asserts that the number of objects falling under the concept "horse" is not zero. This is formally represented using the existential quantifier ($\exists x$), which indicates that a concept is instantiated. By clarifying that existence is a matter of instantiation rather than a descriptive attribute, symbolic logic provided the tools to show that the ontological argument for the existence of God—which relies on treating existence as a perfection or property—is logically unsound.2314