I think therefore, I am

The idea that you are only conscious that you exist, as you are conscious, everything else could be fake, and all a part of your own thoughts, an idea that you only are sure that you exist. Derived from Cogito ergo sum.

Person 1 - "Yo bro do you exist"
Philosopher- "I think therefore, I am"
Person 1 - "Huh?"
Philosopher - "As far as I'm aware, but by that philosophy, you will never know if anything but you exists :)"
Person 1 - "...oh"