...it Is Certain That I

I Am Accustomed To Sleep And In My Dreams To Imagine The Same Things That Lunatics Imagine When Awake.

...it Is Certain That I Am Really Distinct From My Body, And Can Exist Without It.

Everything Is Self-evident.

I Was Convinced That Our Beliefs Are Based Much More On Custom And Example Than On Any Certain Knowledge.

When I Consider This Carefully, I Find Not A Single Property Which With Certainty Separates The Waking State From The Dream. How Can You Be Certain That Your Whole Life Is Not A Dream?