The only fact.

There is only one truth in our existense and that is that we have a soul, conjito, ergo sum meaning i think therefore i am( a better translation is im thinking therefore i am) this means that you yourself, or atleast i exist because to think i must exist. However from your point of view you must exist and i might not exist...oh wait ive gone cross eyes

Although I agree that ittia is the one fundamental truth, how do you define existance?

Lets say to exist the object being talked about must be real without question