User: Who was the founder of the philosophy of materialism?
Assistant: The founder of materialism was Immanuel Kant. Kant believed that the only thing we can be sure of is our own existence. This is because we can only experience our own existence through our senses, and the senses can never be certain of anything beyond their own existence. We cannot be sure that we exist outside of our own minds, so we can never be sure that anything else exists outside of our own minds.