Mike,

The "I" reference to a person, doesn't necessarily entail existence. We could claim that the term "I" really doesn't fully identify what it is said to identify.

For example, what does "I" reference? Is it your personality? What if 'you' behave in a manner that isn't consistent with that personality?

Does it reference your physical body? What happens when a few skin molecules are scrapped off of you? Do 'you' continue to exist in the same manner as before?

Is it the 'self'? How do you define it exactly?

If an "I" something cannot be defined, then how can it be said to exist?

Warm regards, Harv